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core/num/
uint_macros.rs

1macro_rules! uint_impl {
2    (
3        Self = $SelfT:ty,
4        ActualT = $ActualT:ident,
5        SignedT = $SignedT:ident,
6
7        // These are all for use *only* in doc comments.
8        // As such, they're all passed as literals -- passing them as a string
9        // literal is fine if they need to be multiple code tokens.
10        // In non-comments, use the associated constants rather than these.
11        BITS = $BITS:literal,
12        BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
13        MAX = $MaxV:literal,
14        rot = $rot:literal,
15        rot_op = $rot_op:literal,
16        rot_result = $rot_result:literal,
17        fsh_op = $fsh_op:literal,
18        fshl_result = $fshl_result:literal,
19        fshr_result = $fshr_result:literal,
20        clmul_lhs = $clmul_lhs:literal,
21        clmul_rhs = $clmul_rhs:literal,
22        clmul_result = $clmul_result:literal,
23        swap_op = $swap_op:literal,
24        swapped = $swapped:literal,
25        reversed = $reversed:literal,
26        le_bytes = $le_bytes:literal,
27        be_bytes = $be_bytes:literal,
28        to_xe_bytes_doc = $to_xe_bytes_doc:expr,
29        from_xe_bytes_doc = $from_xe_bytes_doc:expr,
30        bound_condition = $bound_condition:literal,
31    ) => {
32        /// The smallest value that can be represented by this integer type.
33        ///
34        /// # Examples
35        ///
36        /// ```
37        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
38        /// ```
39        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
40        pub const MIN: Self = 0;
41
42        /// The largest value that can be represented by this integer type
43        #[doc = concat!("(2<sup>", $BITS, "</sup> &minus; 1", $bound_condition, ").")]
44        ///
45        /// # Examples
46        ///
47        /// ```
48        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
49        /// ```
50        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
51        pub const MAX: Self = !0;
52
53        /// The size of this integer type in bits.
54        ///
55        /// # Examples
56        ///
57        /// ```
58        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
59        /// ```
60        #[stable(feature = "int_bits_const", since = "1.53.0")]
61        pub const BITS: u32 = Self::MAX.count_ones();
62
63        /// Returns the number of ones in the binary representation of `self`.
64        ///
65        /// # Examples
66        ///
67        /// ```
68        #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
69        /// assert_eq!(n.count_ones(), 3);
70        ///
71        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
72        #[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")]
73        ///
74        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
75        /// assert_eq!(zero.count_ones(), 0);
76        /// ```
77        #[stable(feature = "rust1", since = "1.0.0")]
78        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
79        #[doc(alias = "popcount")]
80        #[doc(alias = "popcnt")]
81        #[must_use = "this returns the result of the operation, \
82                      without modifying the original"]
83        #[inline(always)]
84        pub const fn count_ones(self) -> u32 {
85            return intrinsics::ctpop(self);
86        }
87
88        /// Returns the number of zeros in the binary representation of `self`.
89        ///
90        /// # Examples
91        ///
92        /// ```
93        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
94        #[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")]
95        ///
96        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
97        /// assert_eq!(max.count_zeros(), 0);
98        /// ```
99        ///
100        /// This is heavily dependent on the width of the type, and thus
101        /// might give surprising results depending on type inference:
102        /// ```
103        /// # fn foo(_: u8) {}
104        /// # fn bar(_: u16) {}
105        /// let lucky = 7;
106        /// foo(lucky);
107        /// assert_eq!(lucky.count_zeros(), 5);
108        /// assert_eq!(lucky.count_ones(), 3);
109        ///
110        /// let lucky = 7;
111        /// bar(lucky);
112        /// assert_eq!(lucky.count_zeros(), 13);
113        /// assert_eq!(lucky.count_ones(), 3);
114        /// ```
115        /// You might want to use [`Self::count_ones`] instead, or emphasize
116        /// the type you're using in the call rather than method syntax:
117        /// ```
118        /// let small = 1;
119        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::count_zeros(small), ", stringify!($BITS_MINUS_ONE) ,");")]
120        /// ```
121        #[stable(feature = "rust1", since = "1.0.0")]
122        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
123        #[must_use = "this returns the result of the operation, \
124                      without modifying the original"]
125        #[inline(always)]
126        pub const fn count_zeros(self) -> u32 {
127            (!self).count_ones()
128        }
129
130        /// Returns the number of leading zeros in the binary representation of `self`.
131        ///
132        /// Depending on what you're doing with the value, you might also be interested in the
133        /// [`ilog2`] function which returns a consistent number, even if the type widens.
134        ///
135        /// # Examples
136        ///
137        /// ```
138        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
139        /// assert_eq!(n.leading_zeros(), 2);
140        ///
141        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
142        #[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")]
143        ///
144        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
145        /// assert_eq!(max.leading_zeros(), 0);
146        /// ```
147        #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
148        #[stable(feature = "rust1", since = "1.0.0")]
149        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
150        #[must_use = "this returns the result of the operation, \
151                      without modifying the original"]
152        #[inline(always)]
153        pub const fn leading_zeros(self) -> u32 {
154            return intrinsics::ctlz(self as $ActualT);
155        }
156
157        /// Returns the number of trailing zeros in the binary representation
158        /// of `self`.
159        ///
160        /// # Examples
161        ///
162        /// ```
163        #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
164        /// assert_eq!(n.trailing_zeros(), 3);
165        ///
166        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
167        #[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")]
168        ///
169        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
170        #[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")]
171        /// ```
172        #[stable(feature = "rust1", since = "1.0.0")]
173        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
174        #[must_use = "this returns the result of the operation, \
175                      without modifying the original"]
176        #[inline(always)]
177        pub const fn trailing_zeros(self) -> u32 {
178            return intrinsics::cttz(self);
179        }
180
181        /// Returns the number of leading ones in the binary representation of `self`.
182        ///
183        /// # Examples
184        ///
185        /// ```
186        #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
187        /// assert_eq!(n.leading_ones(), 2);
188        ///
189        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
190        /// assert_eq!(zero.leading_ones(), 0);
191        ///
192        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
193        #[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")]
194        /// ```
195        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
196        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
197        #[must_use = "this returns the result of the operation, \
198                      without modifying the original"]
199        #[inline(always)]
200        pub const fn leading_ones(self) -> u32 {
201            (!self).leading_zeros()
202        }
203
204        /// Returns the number of trailing ones in the binary representation
205        /// of `self`.
206        ///
207        /// # Examples
208        ///
209        /// ```
210        #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
211        /// assert_eq!(n.trailing_ones(), 3);
212        ///
213        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
214        /// assert_eq!(zero.trailing_ones(), 0);
215        ///
216        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
217        #[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")]
218        /// ```
219        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
220        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
221        #[must_use = "this returns the result of the operation, \
222                      without modifying the original"]
223        #[inline(always)]
224        pub const fn trailing_ones(self) -> u32 {
225            (!self).trailing_zeros()
226        }
227
228        /// Returns the minimum number of bits required to represent `self`.
229        ///
230        /// This method returns zero if `self` is zero.
231        ///
232        /// # Examples
233        ///
234        /// ```
235        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")]
236        #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")]
237        #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")]
238        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")]
239        /// ```
240        #[stable(feature = "uint_bit_width", since = "CURRENT_RUSTC_VERSION")]
241        #[rustc_const_stable(feature = "uint_bit_width", since = "CURRENT_RUSTC_VERSION")]
242        #[must_use = "this returns the result of the operation, \
243                      without modifying the original"]
244        #[inline(always)]
245        pub const fn bit_width(self) -> u32 {
246            Self::BITS - self.leading_zeros()
247        }
248
249        /// Returns `self` with only the most significant bit set, or `0` if
250        /// the input is `0`.
251        ///
252        /// # Examples
253        ///
254        /// ```
255        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
256        ///
257        /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
258        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
259        /// ```
260        #[stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
261        #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
262        #[must_use = "this returns the result of the operation, \
263                      without modifying the original"]
264        #[inline(always)]
265        pub const fn isolate_highest_one(self) -> Self {
266            self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
267        }
268
269        /// Returns `self` with only the least significant bit set, or `0` if
270        /// the input is `0`.
271        ///
272        /// # Examples
273        ///
274        /// ```
275        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
276        ///
277        /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
278        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
279        /// ```
280        #[stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
281        #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
282        #[must_use = "this returns the result of the operation, \
283                      without modifying the original"]
284        #[inline(always)]
285        pub const fn isolate_lowest_one(self) -> Self {
286            self & self.wrapping_neg()
287        }
288
289        /// Returns the index of the highest bit set to one in `self`, or `None`
290        /// if `self` is `0`.
291        ///
292        /// # Examples
293        ///
294        /// ```
295        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
296        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
297        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
298        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
299        /// ```
300        #[stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
301        #[rustc_const_stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
302        #[must_use = "this returns the result of the operation, \
303                      without modifying the original"]
304        #[inline(always)]
305        pub const fn highest_one(self) -> Option<u32> {
306            match NonZero::new(self) {
307                Some(v) => Some(v.highest_one()),
308                None => None,
309            }
310        }
311
312        /// Returns the index of the lowest bit set to one in `self`, or `None`
313        /// if `self` is `0`.
314        ///
315        /// # Examples
316        ///
317        /// ```
318        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
319        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
320        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
321        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
322        /// ```
323        #[stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
324        #[rustc_const_stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
325        #[must_use = "this returns the result of the operation, \
326                      without modifying the original"]
327        #[inline(always)]
328        pub const fn lowest_one(self) -> Option<u32> {
329            match NonZero::new(self) {
330                Some(v) => Some(v.lowest_one()),
331                None => None,
332            }
333        }
334
335        /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
336        ///
337        /// This produces the same result as an `as` cast, but ensures that the bit-width remains
338        /// the same.
339        ///
340        /// # Examples
341        ///
342        /// ```
343        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")]
344        ///
345        #[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")]
346        /// ```
347        #[stable(feature = "integer_sign_cast", since = "1.87.0")]
348        #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
349        #[must_use = "this returns the result of the operation, \
350                      without modifying the original"]
351        #[inline(always)]
352        pub const fn cast_signed(self) -> $SignedT {
353            self as $SignedT
354        }
355
356        /// Shifts the bits to the left by a specified amount, `n`,
357        /// wrapping the truncated bits to the end of the resulting integer.
358        ///
359        /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
360        /// particular, a rotation by the number of bits in `self` returns the input value
361        /// unchanged.
362        ///
363        /// Please note this isn't the same operation as the `<<` shifting operator!
364        ///
365        /// # Examples
366        ///
367        /// ```
368        #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
369        #[doc = concat!("let m = ", $rot_result, ";")]
370        ///
371        #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
372        #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
373        /// ```
374        #[stable(feature = "rust1", since = "1.0.0")]
375        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
376        #[must_use = "this returns the result of the operation, \
377                      without modifying the original"]
378        #[inline(always)]
379        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
380        pub const fn rotate_left(self, n: u32) -> Self {
381            return intrinsics::rotate_left(self, n);
382        }
383
384        /// Shifts the bits to the right by a specified amount, `n`,
385        /// wrapping the truncated bits to the beginning of the resulting
386        /// integer.
387        ///
388        /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
389        /// particular, a rotation by the number of bits in `self` returns the input value
390        /// unchanged.
391        ///
392        /// Please note this isn't the same operation as the `>>` shifting operator!
393        ///
394        /// # Examples
395        ///
396        /// ```
397        #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
398        #[doc = concat!("let m = ", $rot_op, ";")]
399        ///
400        #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
401        #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
402        /// ```
403        #[stable(feature = "rust1", since = "1.0.0")]
404        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
405        #[must_use = "this returns the result of the operation, \
406                      without modifying the original"]
407        #[inline(always)]
408        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
409        pub const fn rotate_right(self, n: u32) -> Self {
410            return intrinsics::rotate_right(self, n);
411        }
412
413        /// Performs a left funnel shift (concatenates `self` with `rhs`, with `self`
414        /// making up the most significant half, then shifts the combined value left
415        /// by `n`, and most significant half is extracted to produce the result).
416        ///
417        /// Please note this isn't the same operation as the `<<` shifting operator or
418        /// [`rotate_left`](Self::rotate_left), although `a.funnel_shl(a, n)` is *equivalent*
419        /// to `a.rotate_left(n)`.
420        ///
421        /// # Panics
422        ///
423        /// If `n` is greater than or equal to the number of bits in `self`
424        ///
425        /// # Examples
426        ///
427        /// Basic usage:
428        ///
429        /// ```
430        /// #![feature(funnel_shifts)]
431        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
432        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
433        #[doc = concat!("let m = ", $fshl_result, ";")]
434        ///
435        #[doc = concat!("assert_eq!(a.funnel_shl(b, ", $rot, "), m);")]
436        /// ```
437        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
438        #[unstable(feature = "funnel_shifts", issue = "145686")]
439        #[must_use = "this returns the result of the operation, \
440                      without modifying the original"]
441        #[inline(always)]
442        pub const fn funnel_shl(self, rhs: Self, n: u32) -> Self {
443            assert!(n < Self::BITS, "attempt to funnel shift left with overflow");
444            // SAFETY: just checked that `shift` is in-range
445            unsafe { self.unchecked_funnel_shl(rhs, n) }
446        }
447
448        /// Performs a right funnel shift (concatenates `self` and `rhs`, with `self`
449        /// making up the most significant half, then shifts the combined value right
450        /// by `n`, and least significant half is extracted to produce the result).
451        ///
452        /// Please note this isn't the same operation as the `>>` shifting operator or
453        /// [`rotate_right`](Self::rotate_right), although `a.funnel_shr(a, n)` is *equivalent*
454        /// to `a.rotate_right(n)`.
455        ///
456        /// # Panics
457        ///
458        /// If `n` is greater than or equal to the number of bits in `self`
459        ///
460        /// # Examples
461        ///
462        /// Basic usage:
463        ///
464        /// ```
465        /// #![feature(funnel_shifts)]
466        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
467        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
468        #[doc = concat!("let m = ", $fshr_result, ";")]
469        ///
470        #[doc = concat!("assert_eq!(a.funnel_shr(b, ", $rot, "), m);")]
471        /// ```
472        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
473        #[unstable(feature = "funnel_shifts", issue = "145686")]
474        #[must_use = "this returns the result of the operation, \
475                      without modifying the original"]
476        #[inline(always)]
477        pub const fn funnel_shr(self, rhs: Self, n: u32) -> Self {
478            assert!(n < Self::BITS, "attempt to funnel shift right with overflow");
479            // SAFETY: just checked that `shift` is in-range
480            unsafe { self.unchecked_funnel_shr(rhs, n) }
481        }
482
483        /// Unchecked funnel shift left.
484        ///
485        /// # Safety
486        ///
487        /// This results in undefined behavior if `n` is greater than or equal to
488        #[doc = concat!("`", stringify!($SelfT) , "::BITS`,")]
489        /// i.e. when [`funnel_shl`](Self::funnel_shl) would panic.
490        ///
491        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
492        #[unstable(feature = "funnel_shifts", issue = "145686")]
493        #[must_use = "this returns the result of the operation, \
494                      without modifying the original"]
495        #[inline(always)]
496        #[track_caller]
497        pub const unsafe fn unchecked_funnel_shl(self, low: Self, n: u32) -> Self {
498            assert_unsafe_precondition!(
499                check_language_ub,
500                concat!(stringify!($SelfT), "::unchecked_funnel_shl cannot overflow"),
501                (n: u32 = n) => n < <$ActualT>::BITS,
502            );
503
504            // SAFETY: this is guaranteed to be safe by the caller.
505            unsafe {
506                intrinsics::unchecked_funnel_shl(self, low, n)
507            }
508        }
509
510        /// Unchecked funnel shift right.
511        ///
512        /// # Safety
513        ///
514        /// This results in undefined behavior if `n` is greater than or equal to
515        #[doc = concat!("`", stringify!($SelfT) , "::BITS`,")]
516        /// i.e. when [`funnel_shr`](Self::funnel_shr) would panic.
517        ///
518        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
519        #[unstable(feature = "funnel_shifts", issue = "145686")]
520        #[must_use = "this returns the result of the operation, \
521                      without modifying the original"]
522        #[inline(always)]
523        #[track_caller]
524        pub const unsafe fn unchecked_funnel_shr(self, low: Self, n: u32) -> Self {
525            assert_unsafe_precondition!(
526                check_language_ub,
527                concat!(stringify!($SelfT), "::unchecked_funnel_shr cannot overflow"),
528                (n: u32 = n) => n < <$ActualT>::BITS,
529            );
530
531            // SAFETY: this is guaranteed to be safe by the caller.
532            unsafe {
533                intrinsics::unchecked_funnel_shr(self, low, n)
534            }
535        }
536
537        /// Performs a carry-less multiplication, returning the lower bits.
538        ///
539        /// This operation is similar to long multiplication in base 2, except that exclusive or is
540        /// used instead of addition. The implementation is equivalent to:
541        ///
542        /// ```no_run
543        #[doc = concat!("pub fn carryless_mul(lhs: ", stringify!($SelfT), ", rhs: ", stringify!($SelfT), ") -> ", stringify!($SelfT), "{")]
544        ///     let mut retval = 0;
545        #[doc = concat!("    for i in 0..",  stringify!($SelfT), "::BITS {")]
546        ///         if (rhs >> i) & 1 != 0 {
547        ///             // long multiplication would use +=
548        ///             retval ^= lhs << i;
549        ///         }
550        ///     }
551        ///     retval
552        /// }
553        /// ```
554        ///
555        /// The actual implementation is more efficient, and on some platforms lowers directly to a
556        /// dedicated instruction.
557        ///
558        /// # Uses
559        ///
560        /// Carryless multiplication can be used to turn a bitmask of quote characters into a
561        /// bit mask of characters surrounded by quotes:
562        ///
563        /// ```no_run
564        /// r#"abc xxx "foobar" zzz "a"!"#; // input string
565        ///  0b0000000010000001000001010; // quote_mask
566        ///  0b0000000001111110000000100; // quote_mask.carryless_mul(!0) & !quote_mask
567        /// ```
568        ///
569        /// Another use is in cryptography, where carryless multiplication allows for efficient
570        /// implementations of polynomial multiplication in `GF(2)[X]`, the polynomial ring
571        /// over `GF(2)`.
572        ///
573        /// # Examples
574        ///
575        /// ```
576        /// #![feature(uint_carryless_mul)]
577        ///
578        #[doc = concat!("let a = ", $clmul_lhs, stringify!($SelfT), ";")]
579        #[doc = concat!("let b = ", $clmul_rhs, stringify!($SelfT), ";")]
580        ///
581        #[doc = concat!("assert_eq!(a.carryless_mul(b), ", $clmul_result, ");")]
582        /// ```
583        #[rustc_const_unstable(feature = "uint_carryless_mul", issue = "152080")]
584        #[doc(alias = "clmul")]
585        #[unstable(feature = "uint_carryless_mul", issue = "152080")]
586        #[must_use = "this returns the result of the operation, \
587                      without modifying the original"]
588        #[inline(always)]
589        pub const fn carryless_mul(self, rhs: Self) -> Self {
590            intrinsics::carryless_mul(self, rhs)
591        }
592
593        /// Reverses the byte order of the integer.
594        ///
595        /// # Examples
596        ///
597        /// ```
598        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
599        /// let m = n.swap_bytes();
600        ///
601        #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
602        /// ```
603        #[stable(feature = "rust1", since = "1.0.0")]
604        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
605        #[must_use = "this returns the result of the operation, \
606                      without modifying the original"]
607        #[inline(always)]
608        pub const fn swap_bytes(self) -> Self {
609            intrinsics::bswap(self as $ActualT) as Self
610        }
611
612        /// Returns an integer with the bit locations specified by `mask` packed
613        /// contiguously into the least significant bits of the result.
614        /// ```
615        /// #![feature(uint_gather_scatter_bits)]
616        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b1011_1100;")]
617        ///
618        /// assert_eq!(n.extract_bits(0b0010_0100), 0b0000_0011);
619        /// assert_eq!(n.extract_bits(0xF0), 0b0000_1011);
620        /// ```
621        #[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
622        #[must_use = "this returns the result of the operation, \
623                      without modifying the original"]
624        #[inline]
625        pub const fn extract_bits(self, mask: Self) -> Self {
626            imp::int_bits::$ActualT::extract_impl(self as $ActualT, mask as $ActualT) as $SelfT
627        }
628
629        /// Returns an integer with the least significant bits of `self`
630        /// distributed to the bit locations specified by `mask`.
631        /// ```
632        /// #![feature(uint_gather_scatter_bits)]
633        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b1010_1101;")]
634        ///
635        /// assert_eq!(n.deposit_bits(0b0101_0101), 0b0101_0001);
636        /// assert_eq!(n.deposit_bits(0xF0), 0b1101_0000);
637        /// ```
638        #[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
639        #[must_use = "this returns the result of the operation, \
640                      without modifying the original"]
641        #[inline]
642        pub const fn deposit_bits(self, mask: Self) -> Self {
643            imp::int_bits::$ActualT::deposit_impl(self as $ActualT, mask as $ActualT) as $SelfT
644        }
645
646        /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
647        ///                 second least-significant bit becomes second most-significant bit, etc.
648        ///
649        /// # Examples
650        ///
651        /// ```
652        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
653        /// let m = n.reverse_bits();
654        ///
655        #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
656        #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
657        /// ```
658        #[stable(feature = "reverse_bits", since = "1.37.0")]
659        #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
660        #[must_use = "this returns the result of the operation, \
661                      without modifying the original"]
662        #[inline(always)]
663        pub const fn reverse_bits(self) -> Self {
664            intrinsics::bitreverse(self as $ActualT) as Self
665        }
666
667        /// Converts an integer from big endian to the target's endianness.
668        ///
669        /// On big endian this is a no-op. On little endian the bytes are
670        /// swapped.
671        ///
672        /// # Examples
673        ///
674        /// ```
675        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
676        ///
677        /// if cfg!(target_endian = "big") {
678        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
679        /// } else {
680        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
681        /// }
682        /// ```
683        #[stable(feature = "rust1", since = "1.0.0")]
684        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
685        #[must_use]
686        #[inline(always)]
687        pub const fn from_be(x: Self) -> Self {
688            #[cfg(target_endian = "big")]
689            {
690                x
691            }
692            #[cfg(not(target_endian = "big"))]
693            {
694                x.swap_bytes()
695            }
696        }
697
698        /// Converts an integer from little endian to the target's endianness.
699        ///
700        /// On little endian this is a no-op. On big endian the bytes are
701        /// swapped.
702        ///
703        /// # Examples
704        ///
705        /// ```
706        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
707        ///
708        /// if cfg!(target_endian = "little") {
709        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
710        /// } else {
711        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
712        /// }
713        /// ```
714        #[stable(feature = "rust1", since = "1.0.0")]
715        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
716        #[must_use]
717        #[inline(always)]
718        pub const fn from_le(x: Self) -> Self {
719            #[cfg(target_endian = "little")]
720            {
721                x
722            }
723            #[cfg(not(target_endian = "little"))]
724            {
725                x.swap_bytes()
726            }
727        }
728
729        /// Converts `self` to big endian from the target's endianness.
730        ///
731        /// On big endian this is a no-op. On little endian the bytes are
732        /// swapped.
733        ///
734        /// # Examples
735        ///
736        /// ```
737        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
738        ///
739        /// if cfg!(target_endian = "big") {
740        ///     assert_eq!(n.to_be(), n)
741        /// } else {
742        ///     assert_eq!(n.to_be(), n.swap_bytes())
743        /// }
744        /// ```
745        #[stable(feature = "rust1", since = "1.0.0")]
746        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
747        #[must_use = "this returns the result of the operation, \
748                      without modifying the original"]
749        #[inline(always)]
750        pub const fn to_be(self) -> Self { // or not to be?
751            #[cfg(target_endian = "big")]
752            {
753                self
754            }
755            #[cfg(not(target_endian = "big"))]
756            {
757                self.swap_bytes()
758            }
759        }
760
761        /// Converts `self` to little endian from the target's endianness.
762        ///
763        /// On little endian this is a no-op. On big endian the bytes are
764        /// swapped.
765        ///
766        /// # Examples
767        ///
768        /// ```
769        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
770        ///
771        /// if cfg!(target_endian = "little") {
772        ///     assert_eq!(n.to_le(), n)
773        /// } else {
774        ///     assert_eq!(n.to_le(), n.swap_bytes())
775        /// }
776        /// ```
777        #[stable(feature = "rust1", since = "1.0.0")]
778        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
779        #[must_use = "this returns the result of the operation, \
780                      without modifying the original"]
781        #[inline(always)]
782        pub const fn to_le(self) -> Self {
783            #[cfg(target_endian = "little")]
784            {
785                self
786            }
787            #[cfg(not(target_endian = "little"))]
788            {
789                self.swap_bytes()
790            }
791        }
792
793        /// Checked integer addition. Computes `self + rhs`, returning `None`
794        /// if overflow occurred.
795        ///
796        /// # Examples
797        ///
798        /// ```
799        #[doc = concat!(
800            "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
801            "Some(", stringify!($SelfT), "::MAX - 1));"
802        )]
803        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
804        /// ```
805        #[stable(feature = "rust1", since = "1.0.0")]
806        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
807        #[must_use = "this returns the result of the operation, \
808                      without modifying the original"]
809        #[inline]
810        pub const fn checked_add(self, rhs: Self) -> Option<Self> {
811            // This used to use `overflowing_add`, but that means it ends up being
812            // a `wrapping_add`, losing some optimization opportunities. Notably,
813            // phrasing it this way helps `.checked_add(1)` optimize to a check
814            // against `MAX` and a `add nuw`.
815            // Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>,
816            // LLVM is happy to re-form the intrinsic later if useful.
817
818            if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) {
819                None
820            } else {
821                // SAFETY: Just checked it doesn't overflow
822                Some(unsafe { intrinsics::unchecked_add(self, rhs) })
823            }
824        }
825
826        /// Strict integer addition. Computes `self + rhs`, panicking
827        /// if overflow occurred.
828        ///
829        /// # Panics
830        ///
831        /// ## Overflow behavior
832        ///
833        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
834        ///
835        /// # Examples
836        ///
837        /// ```
838        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
839        /// ```
840        ///
841        /// The following panics because of overflow:
842        ///
843        /// ```should_panic
844        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
845        /// ```
846        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
847        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
848        #[must_use = "this returns the result of the operation, \
849                      without modifying the original"]
850        #[inline]
851        #[track_caller]
852        pub const fn strict_add(self, rhs: Self) -> Self {
853            let (a, b) = self.overflowing_add(rhs);
854            if b { imp::overflow_panic::add() } else { a }
855        }
856
857        /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
858        /// cannot occur.
859        ///
860        /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
861        /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
862        ///
863        /// If you're just trying to avoid the panic in debug mode, then **do not**
864        /// use this.  Instead, you're looking for [`wrapping_add`].
865        ///
866        /// # Safety
867        ///
868        /// This results in undefined behavior when
869        #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
870        /// i.e. when [`checked_add`] would return `None`.
871        ///
872        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
873        #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
874        #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
875        #[stable(feature = "unchecked_math", since = "1.79.0")]
876        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
877        #[must_use = "this returns the result of the operation, \
878                      without modifying the original"]
879        #[inline(always)]
880        #[track_caller]
881        pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
882            assert_unsafe_precondition!(
883                check_language_ub,
884                concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
885                (
886                    lhs: $SelfT = self,
887                    rhs: $SelfT = rhs,
888                ) => !lhs.overflowing_add(rhs).1,
889            );
890
891            // SAFETY: this is guaranteed to be safe by the caller.
892            unsafe {
893                intrinsics::unchecked_add(self, rhs)
894            }
895        }
896
897        /// Checked addition with a signed integer. Computes `self + rhs`,
898        /// returning `None` if overflow occurred.
899        ///
900        /// # Examples
901        ///
902        /// ```
903        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
904        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
905        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
906        /// ```
907        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
908        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
909        #[must_use = "this returns the result of the operation, \
910                      without modifying the original"]
911        #[inline]
912        pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
913            let (a, b) = self.overflowing_add_signed(rhs);
914            if intrinsics::unlikely(b) { None } else { Some(a) }
915        }
916
917        /// Strict addition with a signed integer. Computes `self + rhs`,
918        /// panicking if overflow occurred.
919        ///
920        /// # Panics
921        ///
922        /// ## Overflow behavior
923        ///
924        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
925        ///
926        /// # Examples
927        ///
928        /// ```
929        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")]
930        /// ```
931        ///
932        /// The following panic because of overflow:
933        ///
934        /// ```should_panic
935        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")]
936        /// ```
937        ///
938        /// ```should_panic
939        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
940        /// ```
941        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
942        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
943        #[must_use = "this returns the result of the operation, \
944                      without modifying the original"]
945        #[inline]
946        #[track_caller]
947        pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
948            let (a, b) = self.overflowing_add_signed(rhs);
949            if b { imp::overflow_panic::add() } else { a }
950        }
951
952        /// Checked integer subtraction. Computes `self - rhs`, returning
953        /// `None` if overflow occurred.
954        ///
955        /// # Examples
956        ///
957        /// ```
958        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
959        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
960        /// ```
961        #[stable(feature = "rust1", since = "1.0.0")]
962        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
963        #[must_use = "this returns the result of the operation, \
964                      without modifying the original"]
965        #[inline]
966        pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
967            // Per PR#103299, there's no advantage to the `overflowing` intrinsic
968            // for *unsigned* subtraction and we just emit the manual check anyway.
969            // Thus, rather than using `overflowing_sub` that produces a wrapping
970            // subtraction, check it ourself so we can use an unchecked one.
971
972            if self < rhs {
973                None
974            } else {
975                // SAFETY: just checked this can't overflow
976                Some(unsafe { intrinsics::unchecked_sub(self, rhs) })
977            }
978        }
979
980        /// Strict integer subtraction. Computes `self - rhs`, panicking if
981        /// overflow occurred.
982        ///
983        /// # Panics
984        ///
985        /// ## Overflow behavior
986        ///
987        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
988        ///
989        /// # Examples
990        ///
991        /// ```
992        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")]
993        /// ```
994        ///
995        /// The following panics because of overflow:
996        ///
997        /// ```should_panic
998        #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
999        /// ```
1000        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1001        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1002        #[must_use = "this returns the result of the operation, \
1003                      without modifying the original"]
1004        #[inline]
1005        #[track_caller]
1006        pub const fn strict_sub(self, rhs: Self) -> Self {
1007            let (a, b) = self.overflowing_sub(rhs);
1008            if b { imp::overflow_panic::sub() } else { a }
1009        }
1010
1011        /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
1012        /// cannot occur.
1013        ///
1014        /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
1015        /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
1016        ///
1017        /// If you're just trying to avoid the panic in debug mode, then **do not**
1018        /// use this.  Instead, you're looking for [`wrapping_sub`].
1019        ///
1020        /// If you find yourself writing code like this:
1021        ///
1022        /// ```
1023        /// # let foo = 30_u32;
1024        /// # let bar = 20;
1025        /// if foo >= bar {
1026        ///     // SAFETY: just checked it will not overflow
1027        ///     let diff = unsafe { foo.unchecked_sub(bar) };
1028        ///     // ... use diff ...
1029        /// }
1030        /// ```
1031        ///
1032        /// Consider changing it to
1033        ///
1034        /// ```
1035        /// # let foo = 30_u32;
1036        /// # let bar = 20;
1037        /// if let Some(diff) = foo.checked_sub(bar) {
1038        ///     // ... use diff ...
1039        /// }
1040        /// ```
1041        ///
1042        /// As that does exactly the same thing -- including telling the optimizer
1043        /// that the subtraction cannot overflow -- but avoids needing `unsafe`.
1044        ///
1045        /// # Safety
1046        ///
1047        /// This results in undefined behavior when
1048        #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
1049        /// i.e. when [`checked_sub`] would return `None`.
1050        ///
1051        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
1052        #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
1053        #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
1054        #[stable(feature = "unchecked_math", since = "1.79.0")]
1055        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
1056        #[must_use = "this returns the result of the operation, \
1057                      without modifying the original"]
1058        #[inline(always)]
1059        #[track_caller]
1060        pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
1061            assert_unsafe_precondition!(
1062                check_language_ub,
1063                concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
1064                (
1065                    lhs: $SelfT = self,
1066                    rhs: $SelfT = rhs,
1067                ) => !lhs.overflowing_sub(rhs).1,
1068            );
1069
1070            // SAFETY: this is guaranteed to be safe by the caller.
1071            unsafe {
1072                intrinsics::unchecked_sub(self, rhs)
1073            }
1074        }
1075
1076        /// Checked subtraction with a signed integer. Computes `self - rhs`,
1077        /// returning `None` if overflow occurred.
1078        ///
1079        /// # Examples
1080        ///
1081        /// ```
1082        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")]
1083        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")]
1084        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")]
1085        /// ```
1086        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1087        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1088        #[must_use = "this returns the result of the operation, \
1089                      without modifying the original"]
1090        #[inline]
1091        pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> {
1092            let (res, overflow) = self.overflowing_sub_signed(rhs);
1093
1094            if !overflow {
1095                Some(res)
1096            } else {
1097                None
1098            }
1099        }
1100
1101        /// Strict subtraction with a signed integer. Computes `self - rhs`,
1102        /// panicking if overflow occurred.
1103        ///
1104        /// # Panics
1105        ///
1106        /// ## Overflow behavior
1107        ///
1108        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1109        ///
1110        /// # Examples
1111        ///
1112        /// ```
1113        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".strict_sub_signed(2), 1);")]
1114        /// ```
1115        ///
1116        /// The following panic because of overflow:
1117        ///
1118        /// ```should_panic
1119        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_sub_signed(2);")]
1120        /// ```
1121        ///
1122        /// ```should_panic
1123        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
1124        /// ```
1125        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1126        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1127        #[must_use = "this returns the result of the operation, \
1128                      without modifying the original"]
1129        #[inline]
1130        #[track_caller]
1131        pub const fn strict_sub_signed(self, rhs: $SignedT) -> Self {
1132            let (a, b) = self.overflowing_sub_signed(rhs);
1133            if b { imp::overflow_panic::sub() } else { a }
1134        }
1135
1136        #[doc = concat!(
1137            "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`",
1138            stringify!($SignedT), "`], returning `None` if overflow occurred."
1139        )]
1140        ///
1141        /// # Examples
1142        ///
1143        /// ```
1144        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
1145        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
1146        #[doc = concat!(
1147            "assert_eq!(",
1148            stringify!($SelfT),
1149            "::MAX.checked_signed_diff(",
1150            stringify!($SignedT),
1151            "::MAX as ",
1152            stringify!($SelfT),
1153            "), None);"
1154        )]
1155        #[doc = concat!(
1156            "assert_eq!((",
1157            stringify!($SignedT),
1158            "::MAX as ",
1159            stringify!($SelfT),
1160            ").checked_signed_diff(",
1161            stringify!($SelfT),
1162            "::MAX), Some(",
1163            stringify!($SignedT),
1164            "::MIN));"
1165        )]
1166        #[doc = concat!(
1167            "assert_eq!((",
1168            stringify!($SignedT),
1169            "::MAX as ",
1170            stringify!($SelfT),
1171            " + 1).checked_signed_diff(0), None);"
1172        )]
1173        #[doc = concat!(
1174            "assert_eq!(",
1175            stringify!($SelfT),
1176            "::MAX.checked_signed_diff(",
1177            stringify!($SelfT),
1178            "::MAX), Some(0));"
1179        )]
1180        /// ```
1181        #[stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1182        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1183        #[inline]
1184        pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
1185            let res = self.wrapping_sub(rhs) as $SignedT;
1186            let overflow = (self >= rhs) == (res < 0);
1187
1188            if !overflow {
1189                Some(res)
1190            } else {
1191                None
1192            }
1193        }
1194
1195        /// Checked integer multiplication. Computes `self * rhs`, returning
1196        /// `None` if overflow occurred.
1197        ///
1198        /// # Examples
1199        ///
1200        /// ```
1201        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
1202        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
1203        /// ```
1204        #[stable(feature = "rust1", since = "1.0.0")]
1205        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1206        #[must_use = "this returns the result of the operation, \
1207                      without modifying the original"]
1208        #[inline]
1209        pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
1210            let (a, b) = self.overflowing_mul(rhs);
1211            if intrinsics::unlikely(b) { None } else { Some(a) }
1212        }
1213
1214        /// Strict integer multiplication. Computes `self * rhs`, panicking if
1215        /// overflow occurred.
1216        ///
1217        /// # Panics
1218        ///
1219        /// ## Overflow behavior
1220        ///
1221        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1222        ///
1223        /// # Examples
1224        ///
1225        /// ```
1226        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")]
1227        /// ```
1228        ///
1229        /// The following panics because of overflow:
1230        ///
1231        /// ``` should_panic
1232        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
1233        /// ```
1234        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1235        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1236        #[must_use = "this returns the result of the operation, \
1237                      without modifying the original"]
1238        #[inline]
1239        #[track_caller]
1240        pub const fn strict_mul(self, rhs: Self) -> Self {
1241            let (a, b) = self.overflowing_mul(rhs);
1242            if b { imp::overflow_panic::mul() } else { a }
1243        }
1244
1245        /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
1246        /// cannot occur.
1247        ///
1248        /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
1249        /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
1250        ///
1251        /// If you're just trying to avoid the panic in debug mode, then **do not**
1252        /// use this.  Instead, you're looking for [`wrapping_mul`].
1253        ///
1254        /// # Safety
1255        ///
1256        /// This results in undefined behavior when
1257        #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
1258        /// i.e. when [`checked_mul`] would return `None`.
1259        ///
1260        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
1261        #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
1262        #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
1263        #[stable(feature = "unchecked_math", since = "1.79.0")]
1264        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
1265        #[must_use = "this returns the result of the operation, \
1266                      without modifying the original"]
1267        #[inline(always)]
1268        #[track_caller]
1269        pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
1270            assert_unsafe_precondition!(
1271                check_language_ub,
1272                concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
1273                (
1274                    lhs: $SelfT = self,
1275                    rhs: $SelfT = rhs,
1276                ) => !lhs.overflowing_mul(rhs).1,
1277            );
1278
1279            // SAFETY: this is guaranteed to be safe by the caller.
1280            unsafe {
1281                intrinsics::unchecked_mul(self, rhs)
1282            }
1283        }
1284
1285        /// Checked integer division. Computes `self / rhs`, returning `None`
1286        /// if `rhs == 0`.
1287        ///
1288        /// # Examples
1289        ///
1290        /// ```
1291        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
1292        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
1293        /// ```
1294        #[stable(feature = "rust1", since = "1.0.0")]
1295        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1296        #[must_use = "this returns the result of the operation, \
1297                      without modifying the original"]
1298        #[inline]
1299        pub const fn checked_div(self, rhs: Self) -> Option<Self> {
1300            if intrinsics::unlikely(rhs == 0) {
1301                None
1302            } else {
1303                // SAFETY: div by zero has been checked above and unsigned types have no other
1304                // failure modes for division
1305                Some(unsafe { intrinsics::unchecked_div(self, rhs) })
1306            }
1307        }
1308
1309        /// Strict integer division. Computes `self / rhs`.
1310        ///
1311        /// Strict division on unsigned types is just normal division. There's no
1312        /// way overflow could ever happen. This function exists so that all
1313        /// operations are accounted for in the strict operations.
1314        ///
1315        /// # Panics
1316        ///
1317        /// This function will panic if `rhs` is zero.
1318        ///
1319        /// # Examples
1320        ///
1321        /// ```
1322        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")]
1323        /// ```
1324        ///
1325        /// The following panics because of division by zero:
1326        ///
1327        /// ```should_panic
1328        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
1329        /// ```
1330        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1331        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1332        #[must_use = "this returns the result of the operation, \
1333                      without modifying the original"]
1334        #[inline(always)]
1335        #[track_caller]
1336        pub const fn strict_div(self, rhs: Self) -> Self {
1337            self / rhs
1338        }
1339
1340        /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
1341        /// if `rhs == 0`.
1342        ///
1343        /// # Examples
1344        ///
1345        /// ```
1346        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
1347        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
1348        /// ```
1349        #[stable(feature = "euclidean_division", since = "1.38.0")]
1350        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1351        #[must_use = "this returns the result of the operation, \
1352                      without modifying the original"]
1353        #[inline]
1354        pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
1355            if intrinsics::unlikely(rhs == 0) {
1356                None
1357            } else {
1358                Some(self.div_euclid(rhs))
1359            }
1360        }
1361
1362        /// Strict Euclidean division. Computes `self.div_euclid(rhs)`.
1363        ///
1364        /// Strict division on unsigned types is just normal division. There's no
1365        /// way overflow could ever happen. This function exists so that all
1366        /// operations are accounted for in the strict operations. Since, for the
1367        /// positive integers, all common definitions of division are equal, this
1368        /// is exactly equal to `self.strict_div(rhs)`.
1369        ///
1370        /// # Panics
1371        ///
1372        /// This function will panic if `rhs` is zero.
1373        ///
1374        /// # Examples
1375        ///
1376        /// ```
1377        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")]
1378        /// ```
1379        /// The following panics because of division by zero:
1380        ///
1381        /// ```should_panic
1382        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1383        /// ```
1384        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1385        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1386        #[must_use = "this returns the result of the operation, \
1387                      without modifying the original"]
1388        #[inline(always)]
1389        #[track_caller]
1390        pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1391            self / rhs
1392        }
1393
1394        /// Checked integer division without remainder. Computes `self / rhs`,
1395        /// returning `None` if `rhs == 0` or if `self % rhs != 0`.
1396        ///
1397        /// # Examples
1398        ///
1399        /// ```
1400        /// #![feature(exact_div)]
1401        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(2), Some(32));")]
1402        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(32), Some(2));")]
1403        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(0), None);")]
1404        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".checked_div_exact(2), None);")]
1405        /// ```
1406        #[unstable(
1407            feature = "exact_div",
1408            issue = "139911",
1409        )]
1410        #[must_use = "this returns the result of the operation, \
1411                      without modifying the original"]
1412        #[inline]
1413        pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1414            if intrinsics::unlikely(rhs == 0) {
1415                None
1416            } else {
1417                // SAFETY: division by zero is checked above
1418                unsafe {
1419                    if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1420                        None
1421                    } else {
1422                        Some(intrinsics::exact_div(self, rhs))
1423                    }
1424                }
1425            }
1426        }
1427
1428        /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1429        ///
1430        /// # Panics
1431        ///
1432        /// This function will panic  if `rhs == 0`.
1433        ///
1434        /// # Examples
1435        ///
1436        /// ```
1437        /// #![feature(exact_div)]
1438        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1439        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1440        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1441        /// ```
1442        #[unstable(
1443            feature = "exact_div",
1444            issue = "139911",
1445        )]
1446        #[must_use = "this returns the result of the operation, \
1447                      without modifying the original"]
1448        #[inline]
1449        #[rustc_inherit_overflow_checks]
1450        pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1451            if self % rhs != 0 {
1452                None
1453            } else {
1454                Some(self / rhs)
1455            }
1456        }
1457
1458        /// Unchecked integer division without remainder. Computes `self / rhs`.
1459        ///
1460        /// # Safety
1461        ///
1462        /// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`,
1463        /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1464        #[unstable(
1465            feature = "exact_div",
1466            issue = "139911",
1467        )]
1468        #[must_use = "this returns the result of the operation, \
1469                      without modifying the original"]
1470        #[inline]
1471        pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1472            assert_unsafe_precondition!(
1473                check_language_ub,
1474                concat!(stringify!($SelfT), "::unchecked_div_exact divide by zero or leave a remainder"),
1475                (
1476                    lhs: $SelfT = self,
1477                    rhs: $SelfT = rhs,
1478                ) => rhs > 0 && lhs % rhs == 0,
1479            );
1480            // SAFETY: Same precondition
1481            unsafe { intrinsics::exact_div(self, rhs) }
1482        }
1483
1484        /// Checked integer remainder. Computes `self % rhs`, returning `None`
1485        /// if `rhs == 0`.
1486        ///
1487        /// # Examples
1488        ///
1489        /// ```
1490        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1491        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1492        /// ```
1493        #[stable(feature = "wrapping", since = "1.7.0")]
1494        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1495        #[must_use = "this returns the result of the operation, \
1496                      without modifying the original"]
1497        #[inline]
1498        pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1499            if intrinsics::unlikely(rhs == 0) {
1500                None
1501            } else {
1502                // SAFETY: div by zero has been checked above and unsigned types have no other
1503                // failure modes for division
1504                Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1505            }
1506        }
1507
1508        /// Strict integer remainder. Computes `self % rhs`.
1509        ///
1510        /// Strict remainder calculation on unsigned types is just the regular
1511        /// remainder calculation. There's no way overflow could ever happen.
1512        /// This function exists so that all operations are accounted for in the
1513        /// strict operations.
1514        ///
1515        /// # Panics
1516        ///
1517        /// This function will panic if `rhs` is zero.
1518        ///
1519        /// # Examples
1520        ///
1521        /// ```
1522        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")]
1523        /// ```
1524        ///
1525        /// The following panics because of division by zero:
1526        ///
1527        /// ```should_panic
1528        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1529        /// ```
1530        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1531        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1532        #[must_use = "this returns the result of the operation, \
1533                      without modifying the original"]
1534        #[inline(always)]
1535        #[track_caller]
1536        pub const fn strict_rem(self, rhs: Self) -> Self {
1537            self % rhs
1538        }
1539
1540        /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
1541        /// if `rhs == 0`.
1542        ///
1543        /// # Examples
1544        ///
1545        /// ```
1546        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1547        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1548        /// ```
1549        #[stable(feature = "euclidean_division", since = "1.38.0")]
1550        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1551        #[must_use = "this returns the result of the operation, \
1552                      without modifying the original"]
1553        #[inline]
1554        pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1555            if intrinsics::unlikely(rhs == 0) {
1556                None
1557            } else {
1558                Some(self.rem_euclid(rhs))
1559            }
1560        }
1561
1562        /// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`.
1563        ///
1564        /// Strict modulo calculation on unsigned types is just the regular
1565        /// remainder calculation. There's no way overflow could ever happen.
1566        /// This function exists so that all operations are accounted for in the
1567        /// strict operations. Since, for the positive integers, all common
1568        /// definitions of division are equal, this is exactly equal to
1569        /// `self.strict_rem(rhs)`.
1570        ///
1571        /// # Panics
1572        ///
1573        /// This function will panic if `rhs` is zero.
1574        ///
1575        /// # Examples
1576        ///
1577        /// ```
1578        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")]
1579        /// ```
1580        ///
1581        /// The following panics because of division by zero:
1582        ///
1583        /// ```should_panic
1584        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1585        /// ```
1586        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1587        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1588        #[must_use = "this returns the result of the operation, \
1589                      without modifying the original"]
1590        #[inline(always)]
1591        #[track_caller]
1592        pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1593            self % rhs
1594        }
1595
1596        /// Same value as `self | other`, but UB if any bit position is set in both inputs.
1597        ///
1598        /// This is a situational micro-optimization for places where you'd rather
1599        /// use addition on some platforms and bitwise or on other platforms, based
1600        /// on exactly which instructions combine better with whatever else you're
1601        /// doing.  Note that there's no reason to bother using this for places
1602        /// where it's clear from the operations involved that they can't overlap.
1603        /// For example, if you're combining `u16`s into a `u32` with
1604        /// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will
1605        /// know those sides of the `|` are disjoint without needing help.
1606        ///
1607        /// # Examples
1608        ///
1609        /// ```
1610        /// #![feature(disjoint_bitor)]
1611        ///
1612        /// // SAFETY: `1` and `4` have no bits in common.
1613        /// unsafe {
1614        #[doc = concat!("    assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")]
1615        /// }
1616        /// ```
1617        ///
1618        /// # Safety
1619        ///
1620        /// Requires that `(self & other) == 0`, otherwise it's immediate UB.
1621        ///
1622        /// Equivalently, requires that `(self | other) == (self + other)`.
1623        #[unstable(feature = "disjoint_bitor", issue = "135758")]
1624        #[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")]
1625        #[inline]
1626        pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self {
1627            assert_unsafe_precondition!(
1628                check_language_ub,
1629                concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"),
1630                (
1631                    lhs: $SelfT = self,
1632                    rhs: $SelfT = other,
1633                ) => (lhs & rhs) == 0,
1634            );
1635
1636            // SAFETY: Same precondition
1637            unsafe { intrinsics::disjoint_bitor(self, other) }
1638        }
1639
1640        /// Returns the logarithm of the number with respect to an arbitrary base,
1641        /// rounded down.
1642        ///
1643        /// This method might not be optimized owing to implementation details;
1644        /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
1645        /// can produce results more efficiently for base 10.
1646        ///
1647        /// # Panics
1648        ///
1649        /// This function will panic if `self` is zero, or if `base` is less than 2.
1650        ///
1651        /// # Examples
1652        ///
1653        /// ```
1654        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
1655        /// ```
1656        #[stable(feature = "int_log", since = "1.67.0")]
1657        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1658        #[must_use = "this returns the result of the operation, \
1659                      without modifying the original"]
1660        #[inline]
1661        #[track_caller]
1662        pub const fn ilog(self, base: Self) -> u32 {
1663            assert!(base >= 2, "base of integer logarithm must be at least 2");
1664            if let Some(log) = self.checked_ilog(base) {
1665                log
1666            } else {
1667                imp::int_log10::panic_for_nonpositive_argument()
1668            }
1669        }
1670
1671        /// Returns the base 2 logarithm of the number, rounded down.
1672        ///
1673        /// # Panics
1674        ///
1675        /// This function will panic if `self` is zero.
1676        ///
1677        /// # Examples
1678        ///
1679        /// ```
1680        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
1681        /// ```
1682        #[stable(feature = "int_log", since = "1.67.0")]
1683        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1684        #[must_use = "this returns the result of the operation, \
1685                      without modifying the original"]
1686        #[inline]
1687        #[track_caller]
1688        pub const fn ilog2(self) -> u32 {
1689            if let Some(log) = self.checked_ilog2() {
1690                log
1691            } else {
1692                imp::int_log10::panic_for_nonpositive_argument()
1693            }
1694        }
1695
1696        /// Returns the base 10 logarithm of the number, rounded down.
1697        ///
1698        /// # Panics
1699        ///
1700        /// This function will panic if `self` is zero.
1701        ///
1702        /// # Example
1703        ///
1704        /// ```
1705        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
1706        /// ```
1707        #[stable(feature = "int_log", since = "1.67.0")]
1708        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1709        #[must_use = "this returns the result of the operation, \
1710                      without modifying the original"]
1711        #[inline]
1712        #[track_caller]
1713        pub const fn ilog10(self) -> u32 {
1714            if let Some(log) = self.checked_ilog10() {
1715                log
1716            } else {
1717                imp::int_log10::panic_for_nonpositive_argument()
1718            }
1719        }
1720
1721        /// Returns the logarithm of the number with respect to an arbitrary base,
1722        /// rounded down.
1723        ///
1724        /// Returns `None` if the number is zero, or if the base is not at least 2.
1725        ///
1726        /// This method might not be optimized owing to implementation details;
1727        /// `checked_ilog2` can produce results more efficiently for base 2, and
1728        /// `checked_ilog10` can produce results more efficiently for base 10.
1729        ///
1730        /// # Examples
1731        ///
1732        /// ```
1733        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
1734        /// ```
1735        #[stable(feature = "int_log", since = "1.67.0")]
1736        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1737        #[must_use = "this returns the result of the operation, \
1738                      without modifying the original"]
1739        #[inline]
1740        pub const fn checked_ilog(self, base: Self) -> Option<u32> {
1741            // Inform compiler of optimizations when the base is known at
1742            // compile time and there's a cheaper method available.
1743            //
1744            // Note: Like all optimizations, this is not guaranteed to be
1745            // applied by the compiler. If you want those specific bases,
1746            // use `.checked_ilog2()` or `.checked_ilog10()` directly.
1747            if core::intrinsics::is_val_statically_known(base) {
1748                if base == 2 {
1749                    return self.checked_ilog2();
1750                } else if base == 10 {
1751                    return self.checked_ilog10();
1752                }
1753            }
1754
1755            if self <= 0 || base <= 1 {
1756                None
1757            } else if self < base {
1758                Some(0)
1759            } else {
1760                // Since base >= self, n >= 1
1761                let mut n = 1;
1762                let mut r = base;
1763
1764                // Optimization for 128 bit wide integers.
1765                if Self::BITS == 128 {
1766                    // The following is a correct lower bound for ⌊log(base,self)⌋ because
1767                    //
1768                    // log(base,self) = log(2,self) / log(2,base)
1769                    //                ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1)
1770                    //
1771                    // hence
1772                    //
1773                    // ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ .
1774                    n = self.ilog2() / (base.ilog2() + 1);
1775                    r = base.pow(n);
1776                }
1777
1778                while r <= self / base {
1779                    n += 1;
1780                    r *= base;
1781                }
1782                Some(n)
1783            }
1784        }
1785
1786        /// Returns the base 2 logarithm of the number, rounded down.
1787        ///
1788        /// Returns `None` if the number is zero.
1789        ///
1790        /// # Examples
1791        ///
1792        /// ```
1793        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
1794        /// ```
1795        #[stable(feature = "int_log", since = "1.67.0")]
1796        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1797        #[must_use = "this returns the result of the operation, \
1798                      without modifying the original"]
1799        #[inline]
1800        pub const fn checked_ilog2(self) -> Option<u32> {
1801            match NonZero::new(self) {
1802                Some(x) => Some(x.ilog2()),
1803                None => None,
1804            }
1805        }
1806
1807        /// Returns the base 10 logarithm of the number, rounded down.
1808        ///
1809        /// Returns `None` if the number is zero.
1810        ///
1811        /// # Examples
1812        ///
1813        /// ```
1814        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
1815        /// ```
1816        #[stable(feature = "int_log", since = "1.67.0")]
1817        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1818        #[must_use = "this returns the result of the operation, \
1819                      without modifying the original"]
1820        #[inline]
1821        pub const fn checked_ilog10(self) -> Option<u32> {
1822            match NonZero::new(self) {
1823                Some(x) => Some(x.ilog10()),
1824                None => None,
1825            }
1826        }
1827
1828        /// Checked negation. Computes `-self`, returning `None` unless `self ==
1829        /// 0`.
1830        ///
1831        /// Note that negating any positive integer will overflow.
1832        ///
1833        /// # Examples
1834        ///
1835        /// ```
1836        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
1837        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
1838        /// ```
1839        #[stable(feature = "wrapping", since = "1.7.0")]
1840        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1841        #[must_use = "this returns the result of the operation, \
1842                      without modifying the original"]
1843        #[inline]
1844        pub const fn checked_neg(self) -> Option<Self> {
1845            let (a, b) = self.overflowing_neg();
1846            if intrinsics::unlikely(b) { None } else { Some(a) }
1847        }
1848
1849        /// Strict negation. Computes `-self`, panicking unless `self ==
1850        /// 0`.
1851        ///
1852        /// Note that negating any positive integer will overflow.
1853        ///
1854        /// # Panics
1855        ///
1856        /// ## Overflow behavior
1857        ///
1858        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1859        ///
1860        /// # Examples
1861        ///
1862        /// ```
1863        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")]
1864        /// ```
1865        ///
1866        /// The following panics because of overflow:
1867        ///
1868        /// ```should_panic
1869        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
1870        /// ```
1871        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1872        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1873        #[must_use = "this returns the result of the operation, \
1874                      without modifying the original"]
1875        #[inline]
1876        #[track_caller]
1877        pub const fn strict_neg(self) -> Self {
1878            let (a, b) = self.overflowing_neg();
1879            if b { imp::overflow_panic::neg() } else { a }
1880        }
1881
1882        /// Checked shift left. Computes `self << rhs`, returning `None`
1883        /// if `rhs` is larger than or equal to the number of bits in `self`.
1884        ///
1885        /// # Examples
1886        ///
1887        /// ```
1888        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1889        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
1890        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1891        /// ```
1892        #[stable(feature = "wrapping", since = "1.7.0")]
1893        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1894        #[must_use = "this returns the result of the operation, \
1895                      without modifying the original"]
1896        #[inline]
1897        pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1898            // Not using overflowing_shl as that's a wrapping shift
1899            if rhs < Self::BITS {
1900                // SAFETY: just checked the RHS is in-range
1901                Some(unsafe { self.unchecked_shl(rhs) })
1902            } else {
1903                None
1904            }
1905        }
1906
1907        /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1908        /// than or equal to the number of bits in `self`.
1909        ///
1910        /// # Panics
1911        ///
1912        /// ## Overflow behavior
1913        ///
1914        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1915        ///
1916        /// # Examples
1917        ///
1918        /// ```
1919        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1920        /// ```
1921        ///
1922        /// The following panics because of overflow:
1923        ///
1924        /// ```should_panic
1925        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
1926        /// ```
1927        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1928        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1929        #[must_use = "this returns the result of the operation, \
1930                      without modifying the original"]
1931        #[inline]
1932        #[track_caller]
1933        pub const fn strict_shl(self, rhs: u32) -> Self {
1934            let (a, b) = self.overflowing_shl(rhs);
1935            if b { imp::overflow_panic::shl() } else { a }
1936        }
1937
1938        /// Unchecked shift left. Computes `self << rhs`, assuming that
1939        /// `rhs` is less than the number of bits in `self`.
1940        ///
1941        /// # Safety
1942        ///
1943        /// This results in undefined behavior if `rhs` is larger than
1944        /// or equal to the number of bits in `self`,
1945        /// i.e. when [`checked_shl`] would return `None`.
1946        ///
1947        #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1948        #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1949        #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1950        #[must_use = "this returns the result of the operation, \
1951                      without modifying the original"]
1952        #[inline(always)]
1953        #[track_caller]
1954        pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1955            assert_unsafe_precondition!(
1956                check_language_ub,
1957                concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1958                (
1959                    rhs: u32 = rhs,
1960                ) => rhs < <$ActualT>::BITS,
1961            );
1962
1963            // SAFETY: this is guaranteed to be safe by the caller.
1964            unsafe {
1965                intrinsics::unchecked_shl(self, rhs)
1966            }
1967        }
1968
1969        /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1970        ///
1971        /// If `rhs` is larger or equal to the number of bits in `self`,
1972        /// the entire value is shifted out, and `0` is returned.
1973        ///
1974        /// # Examples
1975        ///
1976        /// ```
1977        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1978        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1979        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(0), 0b101);")]
1980        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(1), 0b1010);")]
1981        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(2), 0b10100);")]
1982        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(", stringify!($BITS), "), 0);")]
1983        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1984        ///
1985        #[doc = concat!("let start : ", stringify!($SelfT), " = 13;")]
1986        /// let mut running = start;
1987        /// for i in 0..160 {
1988        ///     // The unbounded shift left by i is the same as `<< 1` i times
1989        ///     assert_eq!(running, start.unbounded_shl(i));
1990        ///     // Which is not always the case for a wrapping shift
1991        #[doc = concat!("    assert_eq!(running == start.wrapping_shl(i), i < ", stringify!($BITS), ");")]
1992        ///
1993        ///     running <<= 1;
1994        /// }
1995        /// ```
1996        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1997        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1998        #[must_use = "this returns the result of the operation, \
1999                      without modifying the original"]
2000        #[inline]
2001        pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
2002            if rhs < Self::BITS {
2003                // SAFETY:
2004                // rhs is just checked to be in-range above
2005                unsafe { self.unchecked_shl(rhs) }
2006            } else {
2007                0
2008            }
2009        }
2010
2011        /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
2012        ///
2013        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
2014        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2015        /// Otherwise, returns `Some(self << rhs)`.
2016        ///
2017        /// # Examples
2018        ///
2019        /// ```
2020        /// #![feature(exact_bitshifts)]
2021        ///
2022        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
2023        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(129), None);")]
2024        /// ```
2025        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2026        #[must_use = "this returns the result of the operation, \
2027                      without modifying the original"]
2028        #[inline]
2029        pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
2030            if rhs <= self.leading_zeros() && rhs < <$SelfT>::BITS {
2031                // SAFETY: rhs is checked above
2032                Some(unsafe { self.unchecked_shl(rhs) })
2033            } else {
2034                None
2035            }
2036        }
2037
2038        /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
2039        /// losslessly reversed `rhs` cannot be larger than
2040        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2041        ///
2042        /// # Safety
2043        ///
2044        /// This results in undefined behavior when `rhs > self.leading_zeros() || rhs >=
2045        #[doc = concat!(stringify!($SelfT), "::BITS`")]
2046        /// i.e. when
2047        #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
2048        /// would return `None`.
2049        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2050        #[must_use = "this returns the result of the operation, \
2051                      without modifying the original"]
2052        #[inline]
2053        pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
2054            assert_unsafe_precondition!(
2055                check_library_ub,
2056                concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out non-zero bits"),
2057                (
2058                    zeros: u32 = self.leading_zeros(),
2059                    bits: u32 =  <$SelfT>::BITS,
2060                    rhs: u32 = rhs,
2061                ) => rhs <= zeros && rhs < bits,
2062            );
2063
2064            // SAFETY: this is guaranteed to be safe by the caller
2065            unsafe { self.unchecked_shl(rhs) }
2066        }
2067
2068        /// Checked shift right. Computes `self >> rhs`, returning `None`
2069        /// if `rhs` is larger than or equal to the number of bits in `self`.
2070        ///
2071        /// # Examples
2072        ///
2073        /// ```
2074        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
2075        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
2076        /// ```
2077        #[stable(feature = "wrapping", since = "1.7.0")]
2078        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
2079        #[must_use = "this returns the result of the operation, \
2080                      without modifying the original"]
2081        #[inline]
2082        pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
2083            // Not using overflowing_shr as that's a wrapping shift
2084            if rhs < Self::BITS {
2085                // SAFETY: just checked the RHS is in-range
2086                Some(unsafe { self.unchecked_shr(rhs) })
2087            } else {
2088                None
2089            }
2090        }
2091
2092        /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
2093        /// larger than or equal to the number of bits in `self`.
2094        ///
2095        /// # Panics
2096        ///
2097        /// ## Overflow behavior
2098        ///
2099        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
2100        ///
2101        /// # Examples
2102        ///
2103        /// ```
2104        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
2105        /// ```
2106        ///
2107        /// The following panics because of overflow:
2108        ///
2109        /// ```should_panic
2110        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
2111        /// ```
2112        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
2113        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
2114        #[must_use = "this returns the result of the operation, \
2115                      without modifying the original"]
2116        #[inline]
2117        #[track_caller]
2118        pub const fn strict_shr(self, rhs: u32) -> Self {
2119            let (a, b) = self.overflowing_shr(rhs);
2120            if b { imp::overflow_panic::shr() } else { a }
2121        }
2122
2123        /// Unchecked shift right. Computes `self >> rhs`, assuming that
2124        /// `rhs` is less than the number of bits in `self`.
2125        ///
2126        /// # Safety
2127        ///
2128        /// This results in undefined behavior if `rhs` is larger than
2129        /// or equal to the number of bits in `self`,
2130        /// i.e. when [`checked_shr`] would return `None`.
2131        ///
2132        #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
2133        #[stable(feature = "unchecked_shifts", since = "1.93.0")]
2134        #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
2135        #[must_use = "this returns the result of the operation, \
2136                      without modifying the original"]
2137        #[inline(always)]
2138        #[track_caller]
2139        pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
2140            assert_unsafe_precondition!(
2141                check_language_ub,
2142                concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
2143                (
2144                    rhs: u32 = rhs,
2145                ) => rhs < <$ActualT>::BITS,
2146            );
2147
2148            // SAFETY: this is guaranteed to be safe by the caller.
2149            unsafe {
2150                intrinsics::unchecked_shr(self, rhs)
2151            }
2152        }
2153
2154        /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
2155        ///
2156        /// If `rhs` is larger or equal to the number of bits in `self`,
2157        /// the entire value is shifted out, and `0` is returned.
2158        ///
2159        /// # Examples
2160        ///
2161        /// ```
2162        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
2163        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(129), 0);")]
2164        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(0), 0b1010);")]
2165        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(1), 0b101);")]
2166        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(2), 0b10);")]
2167        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(", stringify!($BITS), "), 0);")]
2168        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2169        ///
2170        #[doc = concat!("let start = ", stringify!($SelfT), "::rotate_right(13, 4);")]
2171        /// let mut running = start;
2172        /// for i in 0..160 {
2173        ///     // The unbounded shift right by i is the same as `>> 1` i times
2174        ///     assert_eq!(running, start.unbounded_shr(i));
2175        ///     // Which is not always the case for a wrapping shift
2176        #[doc = concat!("    assert_eq!(running == start.wrapping_shr(i), i < ", stringify!($BITS), ");")]
2177        ///
2178        ///     running >>= 1;
2179        /// }
2180        /// ```
2181        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
2182        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
2183        #[must_use = "this returns the result of the operation, \
2184                      without modifying the original"]
2185        #[inline]
2186        pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
2187            if rhs < Self::BITS {
2188                // SAFETY:
2189                // rhs is just checked to be in-range above
2190                unsafe { self.unchecked_shr(rhs) }
2191            } else {
2192                0
2193            }
2194        }
2195
2196        /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
2197        ///
2198        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
2199        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2200        /// Otherwise, returns `Some(self >> rhs)`.
2201        ///
2202        /// # Examples
2203        ///
2204        /// ```
2205        /// #![feature(exact_bitshifts)]
2206        ///
2207        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
2208        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
2209        /// ```
2210        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2211        #[must_use = "this returns the result of the operation, \
2212                      without modifying the original"]
2213        #[inline]
2214        pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
2215            if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
2216                // SAFETY: rhs is checked above
2217                Some(unsafe { self.unchecked_shr(rhs) })
2218            } else {
2219                None
2220            }
2221        }
2222
2223        /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
2224        /// losslessly reversed and `rhs` cannot be larger than
2225        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2226        ///
2227        /// # Safety
2228        ///
2229        /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
2230        #[doc = concat!(stringify!($SelfT), "::BITS`")]
2231        /// i.e. when
2232        #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
2233        /// would return `None`.
2234        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2235        #[must_use = "this returns the result of the operation, \
2236                      without modifying the original"]
2237        #[inline]
2238        pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
2239            assert_unsafe_precondition!(
2240                check_library_ub,
2241                concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
2242                (
2243                    zeros: u32 = self.trailing_zeros(),
2244                    bits: u32 =  <$SelfT>::BITS,
2245                    rhs: u32 = rhs,
2246                ) => rhs <= zeros && rhs < bits,
2247            );
2248
2249            // SAFETY: this is guaranteed to be safe by the caller
2250            unsafe { self.unchecked_shr(rhs) }
2251        }
2252
2253        /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
2254        /// overflow occurred.
2255        ///
2256        /// # Examples
2257        ///
2258        /// ```
2259        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
2260        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
2261        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
2262        /// ```
2263        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2264        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2265        #[must_use = "this returns the result of the operation, \
2266                      without modifying the original"]
2267        #[inline]
2268        pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
2269            if exp == 0 {
2270                return Some(1);
2271            }
2272            let mut base = self;
2273            let mut acc: Self = 1;
2274
2275            loop {
2276                if (exp & 1) == 1 {
2277                    acc = try_opt!(acc.checked_mul(base));
2278                    // since exp!=0, finally the exp must be 1.
2279                    if exp == 1 {
2280                        return Some(acc);
2281                    }
2282                }
2283                exp /= 2;
2284                base = try_opt!(base.checked_mul(base));
2285            }
2286        }
2287
2288        /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
2289        /// overflow occurred.
2290        ///
2291        /// # Panics
2292        ///
2293        /// ## Overflow behavior
2294        ///
2295        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
2296        ///
2297        /// # Examples
2298        ///
2299        /// ```
2300        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")]
2301        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
2302        /// ```
2303        ///
2304        /// The following panics because of overflow:
2305        ///
2306        /// ```should_panic
2307        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
2308        /// ```
2309        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
2310        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
2311        #[must_use = "this returns the result of the operation, \
2312                      without modifying the original"]
2313        #[inline]
2314        #[track_caller]
2315        pub const fn strict_pow(self, mut exp: u32) -> Self {
2316            if exp == 0 {
2317                return 1;
2318            }
2319            let mut base = self;
2320            let mut acc: Self = 1;
2321
2322            loop {
2323                if (exp & 1) == 1 {
2324                    acc = acc.strict_mul(base);
2325                    // since exp!=0, finally the exp must be 1.
2326                    if exp == 1 {
2327                        return acc;
2328                    }
2329                }
2330                exp /= 2;
2331                base = base.strict_mul(base);
2332            }
2333        }
2334
2335        /// Saturating integer addition. Computes `self + rhs`, saturating at
2336        /// the numeric bounds instead of overflowing.
2337        ///
2338        /// # Examples
2339        ///
2340        /// ```
2341        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
2342        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
2343        /// ```
2344        #[stable(feature = "rust1", since = "1.0.0")]
2345        #[must_use = "this returns the result of the operation, \
2346                      without modifying the original"]
2347        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2348        #[inline(always)]
2349        pub const fn saturating_add(self, rhs: Self) -> Self {
2350            intrinsics::saturating_add(self, rhs)
2351        }
2352
2353        /// Saturating addition with a signed integer. Computes `self + rhs`,
2354        /// saturating at the numeric bounds instead of overflowing.
2355        ///
2356        /// # Examples
2357        ///
2358        /// ```
2359        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
2360        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
2361        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
2362        /// ```
2363        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2364        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2365        #[must_use = "this returns the result of the operation, \
2366                      without modifying the original"]
2367        #[inline]
2368        pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
2369            let (res, overflow) = self.overflowing_add(rhs as Self);
2370            if overflow == (rhs < 0) {
2371                res
2372            } else if overflow {
2373                Self::MAX
2374            } else {
2375                0
2376            }
2377        }
2378
2379        /// Saturating integer subtraction. Computes `self - rhs`, saturating
2380        /// at the numeric bounds instead of overflowing.
2381        ///
2382        /// # Examples
2383        ///
2384        /// ```
2385        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
2386        #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
2387        /// ```
2388        #[stable(feature = "rust1", since = "1.0.0")]
2389        #[must_use = "this returns the result of the operation, \
2390                      without modifying the original"]
2391        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2392        #[inline(always)]
2393        pub const fn saturating_sub(self, rhs: Self) -> Self {
2394            intrinsics::saturating_sub(self, rhs)
2395        }
2396
2397        /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
2398        /// the numeric bounds instead of overflowing.
2399        ///
2400        /// # Examples
2401        ///
2402        /// ```
2403        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")]
2404        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")]
2405        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")]
2406        /// ```
2407        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2408        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2409        #[must_use = "this returns the result of the operation, \
2410                      without modifying the original"]
2411        #[inline]
2412        pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self {
2413            let (res, overflow) = self.overflowing_sub_signed(rhs);
2414
2415            if !overflow {
2416                res
2417            } else if rhs < 0 {
2418                Self::MAX
2419            } else {
2420                0
2421            }
2422        }
2423
2424        /// Saturating integer multiplication. Computes `self * rhs`,
2425        /// saturating at the numeric bounds instead of overflowing.
2426        ///
2427        /// # Examples
2428        ///
2429        /// ```
2430        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
2431        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
2432        /// ```
2433        #[stable(feature = "wrapping", since = "1.7.0")]
2434        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2435        #[must_use = "this returns the result of the operation, \
2436                      without modifying the original"]
2437        #[inline]
2438        pub const fn saturating_mul(self, rhs: Self) -> Self {
2439            match self.checked_mul(rhs) {
2440                Some(x) => x,
2441                None => Self::MAX,
2442            }
2443        }
2444
2445        /// Saturating integer division. Computes `self / rhs`, saturating at the
2446        /// numeric bounds instead of overflowing.
2447        ///
2448        /// # Panics
2449        ///
2450        /// This function will panic if `rhs` is zero.
2451        ///
2452        /// # Examples
2453        ///
2454        /// ```
2455        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2456        ///
2457        /// ```
2458        #[stable(feature = "saturating_div", since = "1.58.0")]
2459        #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2460        #[must_use = "this returns the result of the operation, \
2461                      without modifying the original"]
2462        #[inline]
2463        #[track_caller]
2464        pub const fn saturating_div(self, rhs: Self) -> Self {
2465            // on unsigned types, there is no overflow in integer division
2466            self.wrapping_div(rhs)
2467        }
2468
2469        /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2470        /// saturating at the numeric bounds instead of overflowing.
2471        ///
2472        /// # Examples
2473        ///
2474        /// ```
2475        #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
2476        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2477        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2478        /// ```
2479        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2480        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2481        #[must_use = "this returns the result of the operation, \
2482                      without modifying the original"]
2483        #[inline]
2484        pub const fn saturating_pow(self, exp: u32) -> Self {
2485            match self.checked_pow(exp) {
2486                Some(x) => x,
2487                None => Self::MAX,
2488            }
2489        }
2490
2491        /// Wrapping (modular) addition. Computes `self + rhs`,
2492        /// wrapping around at the boundary of the type.
2493        ///
2494        /// # Examples
2495        ///
2496        /// ```
2497        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
2498        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
2499        /// ```
2500        #[stable(feature = "rust1", since = "1.0.0")]
2501        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2502        #[must_use = "this returns the result of the operation, \
2503                      without modifying the original"]
2504        #[inline(always)]
2505        pub const fn wrapping_add(self, rhs: Self) -> Self {
2506            intrinsics::wrapping_add(self, rhs)
2507        }
2508
2509        /// Wrapping (modular) addition with a signed integer. Computes
2510        /// `self + rhs`, wrapping around at the boundary of the type.
2511        ///
2512        /// # Examples
2513        ///
2514        /// ```
2515        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
2516        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
2517        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
2518        /// ```
2519        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2520        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2521        #[must_use = "this returns the result of the operation, \
2522                      without modifying the original"]
2523        #[inline]
2524        pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
2525            self.wrapping_add(rhs as Self)
2526        }
2527
2528        /// Wrapping (modular) subtraction. Computes `self - rhs`,
2529        /// wrapping around at the boundary of the type.
2530        ///
2531        /// # Examples
2532        ///
2533        /// ```
2534        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
2535        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
2536        /// ```
2537        #[stable(feature = "rust1", since = "1.0.0")]
2538        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2539        #[must_use = "this returns the result of the operation, \
2540                      without modifying the original"]
2541        #[inline(always)]
2542        pub const fn wrapping_sub(self, rhs: Self) -> Self {
2543            intrinsics::wrapping_sub(self, rhs)
2544        }
2545
2546        /// Wrapping (modular) subtraction with a signed integer. Computes
2547        /// `self - rhs`, wrapping around at the boundary of the type.
2548        ///
2549        /// # Examples
2550        ///
2551        /// ```
2552        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")]
2553        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")]
2554        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")]
2555        /// ```
2556        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2557        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2558        #[must_use = "this returns the result of the operation, \
2559                      without modifying the original"]
2560        #[inline]
2561        pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self {
2562            self.wrapping_sub(rhs as Self)
2563        }
2564
2565        /// Wrapping (modular) multiplication. Computes `self *
2566        /// rhs`, wrapping around at the boundary of the type.
2567        ///
2568        /// # Examples
2569        ///
2570        /// Please note that this example is shared among integer types, which is why `u8` is used.
2571        ///
2572        /// ```
2573        /// assert_eq!(10u8.wrapping_mul(12), 120);
2574        /// assert_eq!(25u8.wrapping_mul(12), 44);
2575        /// ```
2576        #[stable(feature = "rust1", since = "1.0.0")]
2577        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2578        #[must_use = "this returns the result of the operation, \
2579                      without modifying the original"]
2580        #[inline(always)]
2581        pub const fn wrapping_mul(self, rhs: Self) -> Self {
2582            intrinsics::wrapping_mul(self, rhs)
2583        }
2584
2585        /// Wrapping (modular) division. Computes `self / rhs`.
2586        ///
2587        /// Wrapped division on unsigned types is just normal division. There's
2588        /// no way wrapping could ever happen. This function exists so that all
2589        /// operations are accounted for in the wrapping operations.
2590        ///
2591        /// # Panics
2592        ///
2593        /// This function will panic if `rhs` is zero.
2594        ///
2595        /// # Examples
2596        ///
2597        /// ```
2598        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2599        /// ```
2600        #[stable(feature = "num_wrapping", since = "1.2.0")]
2601        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2602        #[must_use = "this returns the result of the operation, \
2603                      without modifying the original"]
2604        #[inline(always)]
2605        #[track_caller]
2606        pub const fn wrapping_div(self, rhs: Self) -> Self {
2607            self / rhs
2608        }
2609
2610        /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
2611        ///
2612        /// Wrapped division on unsigned types is just normal division. There's
2613        /// no way wrapping could ever happen. This function exists so that all
2614        /// operations are accounted for in the wrapping operations. Since, for
2615        /// the positive integers, all common definitions of division are equal,
2616        /// this is exactly equal to `self.wrapping_div(rhs)`.
2617        ///
2618        /// # Panics
2619        ///
2620        /// This function will panic if `rhs` is zero.
2621        ///
2622        /// # Examples
2623        ///
2624        /// ```
2625        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2626        /// ```
2627        #[stable(feature = "euclidean_division", since = "1.38.0")]
2628        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2629        #[must_use = "this returns the result of the operation, \
2630                      without modifying the original"]
2631        #[inline(always)]
2632        #[track_caller]
2633        pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2634            self / rhs
2635        }
2636
2637        /// Wrapping (modular) remainder. Computes `self % rhs`.
2638        ///
2639        /// Wrapped remainder calculation on unsigned types is just the regular
2640        /// remainder calculation. There's no way wrapping could ever happen.
2641        /// This function exists so that all operations are accounted for in the
2642        /// wrapping operations.
2643        ///
2644        /// # Panics
2645        ///
2646        /// This function will panic if `rhs` is zero.
2647        ///
2648        /// # Examples
2649        ///
2650        /// ```
2651        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2652        /// ```
2653        #[stable(feature = "num_wrapping", since = "1.2.0")]
2654        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2655        #[must_use = "this returns the result of the operation, \
2656                      without modifying the original"]
2657        #[inline(always)]
2658        #[track_caller]
2659        pub const fn wrapping_rem(self, rhs: Self) -> Self {
2660            self % rhs
2661        }
2662
2663        /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
2664        ///
2665        /// Wrapped modulo calculation on unsigned types is just the regular
2666        /// remainder calculation. There's no way wrapping could ever happen.
2667        /// This function exists so that all operations are accounted for in the
2668        /// wrapping operations. Since, for the positive integers, all common
2669        /// definitions of division are equal, this is exactly equal to
2670        /// `self.wrapping_rem(rhs)`.
2671        ///
2672        /// # Panics
2673        ///
2674        /// This function will panic if `rhs` is zero.
2675        ///
2676        /// # Examples
2677        ///
2678        /// ```
2679        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2680        /// ```
2681        #[stable(feature = "euclidean_division", since = "1.38.0")]
2682        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2683        #[must_use = "this returns the result of the operation, \
2684                      without modifying the original"]
2685        #[inline(always)]
2686        #[track_caller]
2687        pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2688            self % rhs
2689        }
2690
2691        /// Wrapping (modular) negation. Computes `-self`,
2692        /// wrapping around at the boundary of the type.
2693        ///
2694        /// Since unsigned types do not have negative equivalents
2695        /// all applications of this function will wrap (except for `-0`).
2696        /// For values smaller than the corresponding signed type's maximum
2697        /// the result is the same as casting the corresponding signed value.
2698        /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
2699        /// `MAX` is the corresponding signed type's maximum.
2700        ///
2701        /// # Examples
2702        ///
2703        /// ```
2704        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
2705        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
2706        #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
2707        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
2708        /// ```
2709        #[stable(feature = "num_wrapping", since = "1.2.0")]
2710        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2711        #[must_use = "this returns the result of the operation, \
2712                      without modifying the original"]
2713        #[inline(always)]
2714        pub const fn wrapping_neg(self) -> Self {
2715            (0 as $SelfT).wrapping_sub(self)
2716        }
2717
2718        /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
2719        /// where `mask` removes any high-order bits of `rhs` that
2720        /// would cause the shift to exceed the bitwidth of the type.
2721        ///
2722        /// Beware that, unlike most other `wrapping_*` methods on integers, this
2723        /// does *not* give the same result as doing the shift in infinite precision
2724        /// then truncating as needed.  The behaviour matches what shift instructions
2725        /// do on many processors, and is what the `<<` operator does when overflow
2726        /// checks are disabled, but numerically it's weird.  Consider, instead,
2727        /// using [`Self::unbounded_shl`] which has nicer behaviour.
2728        ///
2729        /// Note that this is *not* the same as a rotate-left; the
2730        /// RHS of a wrapping shift-left is restricted to the range
2731        /// of the type, rather than the bits shifted out of the LHS
2732        /// being returned to the other end. The primitive integer
2733        /// types all implement a [`rotate_left`](Self::rotate_left) function,
2734        /// which may be what you want instead.
2735        ///
2736        /// # Examples
2737        ///
2738        /// ```
2739        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(7), 128);")]
2740        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(0), 0b101);")]
2741        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(1), 0b1010);")]
2742        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(2), 0b10100);")]
2743        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shl(2), ", stringify!($SelfT), "::MAX - 3);")]
2744        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(", stringify!($BITS), "), 42);")]
2745        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(1).wrapping_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
2746        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(128), 1);")]
2747        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".wrapping_shl(1025), 10);")]
2748        /// ```
2749        #[stable(feature = "num_wrapping", since = "1.2.0")]
2750        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2751        #[must_use = "this returns the result of the operation, \
2752                      without modifying the original"]
2753        #[inline(always)]
2754        pub const fn wrapping_shl(self, rhs: u32) -> Self {
2755            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2756            // out of bounds
2757            unsafe {
2758                self.unchecked_shl(rhs & (Self::BITS - 1))
2759            }
2760        }
2761
2762        /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
2763        /// where `mask` removes any high-order bits of `rhs` that
2764        /// would cause the shift to exceed the bitwidth of the type.
2765        ///
2766        /// Beware that, unlike most other `wrapping_*` methods on integers, this
2767        /// does *not* give the same result as doing the shift in infinite precision
2768        /// then truncating as needed.  The behaviour matches what shift instructions
2769        /// do on many processors, and is what the `>>` operator does when overflow
2770        /// checks are disabled, but numerically it's weird.  Consider, instead,
2771        /// using [`Self::unbounded_shr`] which has nicer behaviour.
2772        ///
2773        /// Note that this is *not* the same as a rotate-right; the
2774        /// RHS of a wrapping shift-right is restricted to the range
2775        /// of the type, rather than the bits shifted out of the LHS
2776        /// being returned to the other end. The primitive integer
2777        /// types all implement a [`rotate_right`](Self::rotate_right) function,
2778        /// which may be what you want instead.
2779        ///
2780        /// # Examples
2781        ///
2782        /// ```
2783        #[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(7), 1);")]
2784        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(0), 0b1010);")]
2785        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(1), 0b101);")]
2786        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(2), 0b10);")]
2787        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shr(1), ", stringify!($SignedT), "::MAX.cast_unsigned());")]
2788        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(", stringify!($BITS), "), 42);")]
2789        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(1).wrapping_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2790        #[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(128), 128);")]
2791        #[doc = concat!("assert_eq!(10_", stringify!($SelfT), ".wrapping_shr(1025), 5);")]
2792        /// ```
2793        #[stable(feature = "num_wrapping", since = "1.2.0")]
2794        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2795        #[must_use = "this returns the result of the operation, \
2796                      without modifying the original"]
2797        #[inline(always)]
2798        pub const fn wrapping_shr(self, rhs: u32) -> Self {
2799            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2800            // out of bounds
2801            unsafe {
2802                self.unchecked_shr(rhs & (Self::BITS - 1))
2803            }
2804        }
2805
2806        /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2807        /// wrapping around at the boundary of the type.
2808        ///
2809        /// # Examples
2810        ///
2811        /// ```
2812        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
2813        /// assert_eq!(3u8.wrapping_pow(6), 217);
2814        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2815        /// ```
2816        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2817        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2818        #[must_use = "this returns the result of the operation, \
2819                      without modifying the original"]
2820        #[inline]
2821        pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2822            if exp == 0 {
2823                return 1;
2824            }
2825            let mut base = self;
2826            let mut acc: Self = 1;
2827
2828            if intrinsics::is_val_statically_known(exp) {
2829                while exp > 1 {
2830                    if (exp & 1) == 1 {
2831                        acc = acc.wrapping_mul(base);
2832                    }
2833                    exp /= 2;
2834                    base = base.wrapping_mul(base);
2835                }
2836
2837                // since exp!=0, finally the exp must be 1.
2838                // Deal with the final bit of the exponent separately, since
2839                // squaring the base afterwards is not necessary.
2840                acc.wrapping_mul(base)
2841            } else {
2842                // This is faster than the above when the exponent is not known
2843                // at compile time. We can't use the same code for the constant
2844                // exponent case because LLVM is currently unable to unroll
2845                // this loop.
2846                loop {
2847                    if (exp & 1) == 1 {
2848                        acc = acc.wrapping_mul(base);
2849                        // since exp!=0, finally the exp must be 1.
2850                        if exp == 1 {
2851                            return acc;
2852                        }
2853                    }
2854                    exp /= 2;
2855                    base = base.wrapping_mul(base);
2856                }
2857            }
2858        }
2859
2860        /// Calculates `self` + `rhs`.
2861        ///
2862        /// Returns a tuple of the addition along with a boolean indicating
2863        /// whether an arithmetic overflow would occur. If an overflow would
2864        /// have occurred then the wrapped value is returned.
2865        ///
2866        /// # Examples
2867        ///
2868        /// ```
2869        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2870        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
2871        /// ```
2872        #[stable(feature = "wrapping", since = "1.7.0")]
2873        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2874        #[must_use = "this returns the result of the operation, \
2875                      without modifying the original"]
2876        #[inline(always)]
2877        pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2878            let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2879            (a as Self, b)
2880        }
2881
2882        /// Calculates `self` + `rhs` + `carry` and returns a tuple containing
2883        /// the sum and the output carry (in that order).
2884        ///
2885        /// Performs "ternary addition" of two integer operands and a carry-in
2886        /// bit, and returns an output integer and a carry-out bit. This allows
2887        /// chaining together multiple additions to create a wider addition, and
2888        /// can be useful for bignum addition.
2889        ///
2890        #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
2891        ///
2892        /// If the input carry is false, this method is equivalent to
2893        /// [`overflowing_add`](Self::overflowing_add), and the output carry is
2894        /// equal to the overflow flag. Note that although carry and overflow
2895        /// flags are similar for unsigned integers, they are different for
2896        /// signed integers.
2897        ///
2898        /// # Examples
2899        ///
2900        /// ```
2901        #[doc = concat!("//    3  MAX    (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2902        #[doc = concat!("// +  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2903        /// // ---------
2904        #[doc = concat!("//    9    6    (sum = 9 × 2^", stringify!($BITS), " + 6)")]
2905        ///
2906        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
2907        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2908        /// let carry0 = false;
2909        ///
2910        /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2911        /// assert_eq!(carry1, true);
2912        /// let (sum1, carry2) = a1.carrying_add(b1, carry1);
2913        /// assert_eq!(carry2, false);
2914        ///
2915        /// assert_eq!((sum1, sum0), (9, 6));
2916        /// ```
2917        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
2918        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
2919        #[must_use = "this returns the result of the operation, \
2920                      without modifying the original"]
2921        #[inline]
2922        pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2923            // note: longer-term this should be done via an intrinsic, but this has been shown
2924            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2925            let (a, c1) = self.overflowing_add(rhs);
2926            let (b, c2) = a.overflowing_add(carry as $SelfT);
2927            // Ideally LLVM would know this is disjoint without us telling them,
2928            // but it doesn't <https://github.com/llvm/llvm-project/issues/118162>
2929            // SAFETY: Only one of `c1` and `c2` can be set.
2930            // For c1 to be set we need to have overflowed, but if we did then
2931            // `a` is at most `MAX-1`, which means that `c2` cannot possibly
2932            // overflow because it's adding at most `1` (since it came from `bool`)
2933            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2934        }
2935
2936        /// Calculates `self` + `rhs` with a signed `rhs`.
2937        ///
2938        /// Returns a tuple of the addition along with a boolean indicating
2939        /// whether an arithmetic overflow would occur. If an overflow would
2940        /// have occurred then the wrapped value is returned.
2941        ///
2942        /// # Examples
2943        ///
2944        /// ```
2945        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
2946        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
2947        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
2948        /// ```
2949        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2950        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2951        #[must_use = "this returns the result of the operation, \
2952                      without modifying the original"]
2953        #[inline]
2954        pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
2955            let (res, overflowed) = self.overflowing_add(rhs as Self);
2956            (res, overflowed ^ (rhs < 0))
2957        }
2958
2959        /// Calculates `self` - `rhs`.
2960        ///
2961        /// Returns a tuple of the subtraction along with a boolean indicating
2962        /// whether an arithmetic overflow would occur. If an overflow would
2963        /// have occurred then the wrapped value is returned.
2964        ///
2965        /// # Examples
2966        ///
2967        /// ```
2968        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2969        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2970        /// ```
2971        #[stable(feature = "wrapping", since = "1.7.0")]
2972        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2973        #[must_use = "this returns the result of the operation, \
2974                      without modifying the original"]
2975        #[inline(always)]
2976        pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2977            let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2978            (a as Self, b)
2979        }
2980
2981        /// Calculates `self` &minus; `rhs` &minus; `borrow` and returns a tuple
2982        /// containing the difference and the output borrow.
2983        ///
2984        /// Performs "ternary subtraction" by subtracting both an integer
2985        /// operand and a borrow-in bit from `self`, and returns an output
2986        /// integer and a borrow-out bit. This allows chaining together multiple
2987        /// subtractions to create a wider subtraction, and can be useful for
2988        /// bignum subtraction.
2989        ///
2990        /// # Examples
2991        ///
2992        /// ```
2993        #[doc = concat!("//    9    6    (a = 9 × 2^", stringify!($BITS), " + 6)")]
2994        #[doc = concat!("// -  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2995        /// // ---------
2996        #[doc = concat!("//    3  MAX    (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2997        ///
2998        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
2999        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
3000        /// let borrow0 = false;
3001        ///
3002        /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
3003        /// assert_eq!(borrow1, true);
3004        /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
3005        /// assert_eq!(borrow2, false);
3006        ///
3007        #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
3008        /// ```
3009        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3010        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
3011        #[must_use = "this returns the result of the operation, \
3012                      without modifying the original"]
3013        #[inline]
3014        pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
3015            // note: longer-term this should be done via an intrinsic, but this has been shown
3016            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
3017            let (a, c1) = self.overflowing_sub(rhs);
3018            let (b, c2) = a.overflowing_sub(borrow as $SelfT);
3019            // SAFETY: Only one of `c1` and `c2` can be set.
3020            // For c1 to be set we need to have underflowed, but if we did then
3021            // `a` is nonzero, which means that `c2` cannot possibly
3022            // underflow because it's subtracting at most `1` (since it came from `bool`)
3023            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
3024        }
3025
3026        /// Calculates `self` - `rhs` with a signed `rhs`
3027        ///
3028        /// Returns a tuple of the subtraction along with a boolean indicating
3029        /// whether an arithmetic overflow would occur. If an overflow would
3030        /// have occurred then the wrapped value is returned.
3031        ///
3032        /// # Examples
3033        ///
3034        /// ```
3035        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")]
3036        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")]
3037        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")]
3038        /// ```
3039        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
3040        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
3041        #[must_use = "this returns the result of the operation, \
3042                      without modifying the original"]
3043        #[inline]
3044        pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) {
3045            let (res, overflow) = self.overflowing_sub(rhs as Self);
3046
3047            (res, overflow ^ (rhs < 0))
3048        }
3049
3050        /// Computes the absolute difference between `self` and `other`.
3051        ///
3052        /// # Examples
3053        ///
3054        /// ```
3055        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
3056        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
3057        /// ```
3058        #[stable(feature = "int_abs_diff", since = "1.60.0")]
3059        #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3060        #[must_use = "this returns the result of the operation, \
3061                      without modifying the original"]
3062        #[inline]
3063        pub const fn abs_diff(self, other: Self) -> Self {
3064            if size_of::<Self>() == 1 {
3065                // Trick LLVM into generating the psadbw instruction when SSE2
3066                // is available and this function is autovectorized for u8's.
3067                (self as i32).wrapping_sub(other as i32).unsigned_abs() as Self
3068            } else {
3069                if self < other {
3070                    other - self
3071                } else {
3072                    self - other
3073                }
3074            }
3075        }
3076
3077        /// Calculates the multiplication of `self` and `rhs`.
3078        ///
3079        /// Returns a tuple of the multiplication along with a boolean
3080        /// indicating whether an arithmetic overflow would occur. If an
3081        /// overflow would have occurred then the wrapped value is returned.
3082        ///
3083        /// If you want the *value* of the overflow, rather than just *whether*
3084        /// an overflow occurred, see [`Self::carrying_mul`].
3085        ///
3086        /// # Examples
3087        ///
3088        /// Please note that this example is shared among integer types, which is why `u32` is used.
3089        ///
3090        /// ```
3091        /// assert_eq!(5u32.overflowing_mul(2), (10, false));
3092        /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
3093        /// ```
3094        #[stable(feature = "wrapping", since = "1.7.0")]
3095        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3096        #[must_use = "this returns the result of the operation, \
3097                          without modifying the original"]
3098        #[inline(always)]
3099        pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
3100            let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
3101            (a as Self, b)
3102        }
3103
3104        /// Calculates the complete double-width product `self * rhs`.
3105        ///
3106        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3107        /// of the result as two separate values, in that order. As such,
3108        /// `a.widening_mul(b).0` produces the same result as `a.wrapping_mul(b)`.
3109        ///
3110        /// If you also need to add a value and carry to the wide result, then you want
3111        /// [`Self::carrying_mul_add`] instead.
3112        ///
3113        /// If you also need to add a carry to the wide result, then you want
3114        /// [`Self::carrying_mul`] instead.
3115        ///
3116        /// If you just want to know *whether* the multiplication overflowed, then you
3117        /// want [`Self::overflowing_mul`] instead.
3118        ///
3119        /// # Examples
3120        ///
3121        /// ```
3122        /// #![feature(widening_mul)]
3123        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".widening_mul(7), (35, 0));")]
3124        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.widening_mul(", stringify!($SelfT), "::MAX), (1, ", stringify!($SelfT), "::MAX - 1));")]
3125        /// ```
3126        ///
3127        /// Compared to other `*_mul` methods:
3128        /// ```
3129        /// #![feature(widening_mul)]
3130        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::widening_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, 3));")]
3131        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::overflowing_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, true));")]
3132        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::wrapping_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), 0);")]
3133        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::checked_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), None);")]
3134        /// ```
3135        ///
3136        /// Please note that this example is shared among integer types, which is why `u32` is used.
3137        ///
3138        /// ```
3139        /// #![feature(widening_mul)]
3140        /// assert_eq!(5u32.widening_mul(2), (10, 0));
3141        /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
3142        /// ```
3143        #[unstable(feature = "widening_mul", issue = "152016")]
3144        #[rustc_const_unstable(feature = "widening_mul", issue = "152016")]
3145        #[must_use = "this returns the result of the operation, \
3146                      without modifying the original"]
3147        #[inline]
3148        pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
3149            Self::carrying_mul_add(self, rhs, 0, 0)
3150        }
3151
3152        /// Calculates the "full multiplication" `self * rhs + carry`
3153        /// without the possibility to overflow.
3154        ///
3155        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3156        /// of the result as two separate values, in that order.
3157        ///
3158        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
3159        /// additional amount of overflow. This allows for chaining together multiple
3160        /// multiplications to create "big integers" which represent larger values.
3161        ///
3162        /// If you also need to add a value, then use [`Self::carrying_mul_add`].
3163        ///
3164        /// # Examples
3165        ///
3166        /// Please note that this example is shared among integer types, which is why `u32` is used.
3167        ///
3168        /// ```
3169        /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
3170        /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
3171        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
3172        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
3173        #[doc = concat!("assert_eq!(",
3174            stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
3175            "(0, ", stringify!($SelfT), "::MAX));"
3176        )]
3177        /// ```
3178        ///
3179        /// This is the core operation needed for scalar multiplication when
3180        /// implementing it for wider-than-native types.
3181        ///
3182        /// ```
3183        /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
3184        ///     let mut carry = 0;
3185        ///     for d in little_endian_digits.iter_mut() {
3186        ///         (*d, carry) = d.carrying_mul(multiplicand, carry);
3187        ///     }
3188        ///     if carry != 0 {
3189        ///         little_endian_digits.push(carry);
3190        ///     }
3191        /// }
3192        ///
3193        /// let mut v = vec![10, 20];
3194        /// scalar_mul_eq(&mut v, 3);
3195        /// assert_eq!(v, [30, 60]);
3196        ///
3197        /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
3198        /// let mut v = vec![0x4321, 0x8765];
3199        /// scalar_mul_eq(&mut v, 0xFEED);
3200        /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
3201        /// ```
3202        ///
3203        /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
3204        /// except that it gives the value of the overflow instead of just whether one happened:
3205        ///
3206        /// ```
3207        /// # #![allow(unused_features)]
3208        /// #![feature(const_unsigned_bigint_helpers)]
3209        /// let r = u8::carrying_mul(7, 13, 0);
3210        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13));
3211        /// let r = u8::carrying_mul(13, 42, 0);
3212        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42));
3213        /// ```
3214        ///
3215        /// The value of the first field in the returned tuple matches what you'd get
3216        /// by combining the [`wrapping_mul`](Self::wrapping_mul) and
3217        /// [`wrapping_add`](Self::wrapping_add) methods:
3218        ///
3219        /// ```
3220        /// # #![allow(unused_features)]
3221        /// #![feature(const_unsigned_bigint_helpers)]
3222        /// assert_eq!(
3223        ///     789_u16.carrying_mul(456, 123).0,
3224        ///     789_u16.wrapping_mul(456).wrapping_add(123),
3225        /// );
3226        /// ```
3227        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3228        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
3229        #[must_use = "this returns the result of the operation, \
3230                      without modifying the original"]
3231        #[inline]
3232        pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
3233            Self::carrying_mul_add(self, rhs, carry, 0)
3234        }
3235
3236        /// Calculates the "full multiplication" `self * rhs + carry + add`.
3237        ///
3238        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3239        /// of the result as two separate values, in that order.
3240        ///
3241        /// This cannot overflow, as the double-width result has exactly enough
3242        /// space for the largest possible result. This is equivalent to how, in
3243        /// decimal, 9 × 9 + 9 + 9 = 81 + 18 = 99 = 9×10⁰ + 9×10¹ = 10² - 1.
3244        ///
3245        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
3246        /// additional amount of overflow. This allows for chaining together multiple
3247        /// multiplications to create "big integers" which represent larger values.
3248        ///
3249        /// If you don't need the `add` part, then you can use [`Self::carrying_mul`] instead.
3250        ///
3251        /// # Examples
3252        ///
3253        /// Please note that this example is shared between integer types,
3254        /// which explains why `u32` is used here.
3255        ///
3256        /// ```
3257        /// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0));
3258        /// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0));
3259        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2));
3260        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2));
3261        #[doc = concat!("assert_eq!(",
3262            stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
3263            "(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));"
3264        )]
3265        /// ```
3266        ///
3267        /// This is the core per-digit operation for "grade school" O(n²) multiplication.
3268        ///
3269        /// Please note that this example is shared between integer types,
3270        /// using `u8` for simplicity of the demonstration.
3271        ///
3272        /// ```
3273        /// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] {
3274        ///     let mut out = [0; N];
3275        ///     for j in 0..N {
3276        ///         let mut carry = 0;
3277        ///         for i in 0..(N - j) {
3278        ///             (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry);
3279        ///         }
3280        ///     }
3281        ///     out
3282        /// }
3283        ///
3284        /// // -1 * -1 == 1
3285        /// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]);
3286        ///
3287        /// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xcffc982d);
3288        /// assert_eq!(
3289        ///     quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)),
3290        ///     u32::to_le_bytes(0xcffc982d)
3291        /// );
3292        /// ```
3293        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3294        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
3295        #[must_use = "this returns the result of the operation, \
3296                      without modifying the original"]
3297        #[inline]
3298        pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) {
3299            intrinsics::carrying_mul_add(self, rhs, carry, add)
3300        }
3301
3302        /// Calculates the divisor when `self` is divided by `rhs`.
3303        ///
3304        /// Returns a tuple of the divisor along with a boolean indicating
3305        /// whether an arithmetic overflow would occur. Note that for unsigned
3306        /// integers overflow never occurs, so the second value is always
3307        /// `false`.
3308        ///
3309        /// # Panics
3310        ///
3311        /// This function will panic if `rhs` is zero.
3312        ///
3313        /// # Examples
3314        ///
3315        /// ```
3316        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
3317        /// ```
3318        #[inline(always)]
3319        #[stable(feature = "wrapping", since = "1.7.0")]
3320        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3321        #[must_use = "this returns the result of the operation, \
3322                      without modifying the original"]
3323        #[track_caller]
3324        pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
3325            (self / rhs, false)
3326        }
3327
3328        /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
3329        ///
3330        /// Returns a tuple of the divisor along with a boolean indicating
3331        /// whether an arithmetic overflow would occur. Note that for unsigned
3332        /// integers overflow never occurs, so the second value is always
3333        /// `false`.
3334        /// Since, for the positive integers, all common
3335        /// definitions of division are equal, this
3336        /// is exactly equal to `self.overflowing_div(rhs)`.
3337        ///
3338        /// # Panics
3339        ///
3340        /// This function will panic if `rhs` is zero.
3341        ///
3342        /// # Examples
3343        ///
3344        /// ```
3345        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
3346        /// ```
3347        #[inline(always)]
3348        #[stable(feature = "euclidean_division", since = "1.38.0")]
3349        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3350        #[must_use = "this returns the result of the operation, \
3351                      without modifying the original"]
3352        #[track_caller]
3353        pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
3354            (self / rhs, false)
3355        }
3356
3357        /// Calculates the remainder when `self` is divided by `rhs`.
3358        ///
3359        /// Returns a tuple of the remainder after dividing along with a boolean
3360        /// indicating whether an arithmetic overflow would occur. Note that for
3361        /// unsigned integers overflow never occurs, so the second value is
3362        /// always `false`.
3363        ///
3364        /// # Panics
3365        ///
3366        /// This function will panic if `rhs` is zero.
3367        ///
3368        /// # Examples
3369        ///
3370        /// ```
3371        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
3372        /// ```
3373        #[inline(always)]
3374        #[stable(feature = "wrapping", since = "1.7.0")]
3375        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3376        #[must_use = "this returns the result of the operation, \
3377                      without modifying the original"]
3378        #[track_caller]
3379        pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
3380            (self % rhs, false)
3381        }
3382
3383        /// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division.
3384        ///
3385        /// Returns a tuple of the modulo after dividing along with a boolean
3386        /// indicating whether an arithmetic overflow would occur. Note that for
3387        /// unsigned integers overflow never occurs, so the second value is
3388        /// always `false`.
3389        /// Since, for the positive integers, all common
3390        /// definitions of division are equal, this operation
3391        /// is exactly equal to `self.overflowing_rem(rhs)`.
3392        ///
3393        /// # Panics
3394        ///
3395        /// This function will panic if `rhs` is zero.
3396        ///
3397        /// # Examples
3398        ///
3399        /// ```
3400        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
3401        /// ```
3402        #[inline(always)]
3403        #[stable(feature = "euclidean_division", since = "1.38.0")]
3404        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3405        #[must_use = "this returns the result of the operation, \
3406                      without modifying the original"]
3407        #[track_caller]
3408        pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
3409            (self % rhs, false)
3410        }
3411
3412        /// Negates self in an overflowing fashion.
3413        ///
3414        /// Returns `!self + 1` using wrapping operations to return the value
3415        /// that represents the negation of this unsigned value. Note that for
3416        /// positive unsigned values overflow always occurs, but negating 0 does
3417        /// not overflow.
3418        ///
3419        /// # Examples
3420        ///
3421        /// ```
3422        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
3423        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
3424        /// ```
3425        #[inline(always)]
3426        #[stable(feature = "wrapping", since = "1.7.0")]
3427        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3428        #[must_use = "this returns the result of the operation, \
3429                      without modifying the original"]
3430        pub const fn overflowing_neg(self) -> (Self, bool) {
3431            ((!self).wrapping_add(1), self != 0)
3432        }
3433
3434        /// Shifts self left by `rhs` bits.
3435        ///
3436        /// Returns a tuple of the shifted version of self along with a boolean
3437        /// indicating whether the shift value was larger than or equal to the
3438        /// number of bits. If the shift value is too large, then value is
3439        /// masked (N-1) where N is the number of bits, and this value is then
3440        /// used to perform the shift.
3441        ///
3442        /// # Examples
3443        ///
3444        /// ```
3445        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
3446        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
3447        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
3448        /// ```
3449        #[stable(feature = "wrapping", since = "1.7.0")]
3450        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3451        #[must_use = "this returns the result of the operation, \
3452                      without modifying the original"]
3453        #[inline(always)]
3454        pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
3455            (self.wrapping_shl(rhs), rhs >= Self::BITS)
3456        }
3457
3458        /// Shifts self right by `rhs` bits.
3459        ///
3460        /// Returns a tuple of the shifted version of self along with a boolean
3461        /// indicating whether the shift value was larger than or equal to the
3462        /// number of bits. If the shift value is too large, then value is
3463        /// masked (N-1) where N is the number of bits, and this value is then
3464        /// used to perform the shift.
3465        ///
3466        /// # Examples
3467        ///
3468        /// ```
3469        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
3470        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
3471        /// ```
3472        #[stable(feature = "wrapping", since = "1.7.0")]
3473        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3474        #[must_use = "this returns the result of the operation, \
3475                      without modifying the original"]
3476        #[inline(always)]
3477        pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
3478            (self.wrapping_shr(rhs), rhs >= Self::BITS)
3479        }
3480
3481        /// Raises self to the power of `exp`, using exponentiation by squaring.
3482        ///
3483        /// Returns a tuple of the exponentiation along with a bool indicating
3484        /// whether an overflow happened.
3485        ///
3486        /// # Examples
3487        ///
3488        /// ```
3489        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
3490        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
3491        /// assert_eq!(3u8.overflowing_pow(6), (217, true));
3492        /// ```
3493        #[stable(feature = "no_panic_pow", since = "1.34.0")]
3494        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3495        #[must_use = "this returns the result of the operation, \
3496                      without modifying the original"]
3497        #[inline]
3498        pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3499            if exp == 0{
3500                return (1,false);
3501            }
3502            let mut base = self;
3503            let mut acc: Self = 1;
3504            let mut overflown = false;
3505            // Scratch space for storing results of overflowing_mul.
3506            let mut r;
3507
3508            loop {
3509                if (exp & 1) == 1 {
3510                    r = acc.overflowing_mul(base);
3511                    // since exp!=0, finally the exp must be 1.
3512                    if exp == 1 {
3513                        r.1 |= overflown;
3514                        return r;
3515                    }
3516                    acc = r.0;
3517                    overflown |= r.1;
3518                }
3519                exp /= 2;
3520                r = base.overflowing_mul(base);
3521                base = r.0;
3522                overflown |= r.1;
3523            }
3524        }
3525
3526        /// Raises self to the power of `exp`, using exponentiation by squaring.
3527        ///
3528        /// # Examples
3529        ///
3530        /// ```
3531        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
3532        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3533        /// ```
3534        #[stable(feature = "rust1", since = "1.0.0")]
3535        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3536        #[must_use = "this returns the result of the operation, \
3537                      without modifying the original"]
3538        #[inline]
3539        #[rustc_inherit_overflow_checks]
3540        pub const fn pow(self, mut exp: u32) -> Self {
3541            if exp == 0 {
3542                return 1;
3543            }
3544            let mut base = self;
3545            let mut acc = 1;
3546
3547            if intrinsics::is_val_statically_known(exp) {
3548                while exp > 1 {
3549                    if (exp & 1) == 1 {
3550                        acc = acc * base;
3551                    }
3552                    exp /= 2;
3553                    base = base * base;
3554                }
3555
3556                // since exp!=0, finally the exp must be 1.
3557                // Deal with the final bit of the exponent separately, since
3558                // squaring the base afterwards is not necessary and may cause a
3559                // needless overflow.
3560                acc * base
3561            } else {
3562                // This is faster than the above when the exponent is not known
3563                // at compile time. We can't use the same code for the constant
3564                // exponent case because LLVM is currently unable to unroll
3565                // this loop.
3566                loop {
3567                    if (exp & 1) == 1 {
3568                        acc = acc * base;
3569                        // since exp!=0, finally the exp must be 1.
3570                        if exp == 1 {
3571                            return acc;
3572                        }
3573                    }
3574                    exp /= 2;
3575                    base = base * base;
3576                }
3577            }
3578        }
3579
3580        /// Returns the square root of the number, rounded down.
3581        ///
3582        /// # Examples
3583        ///
3584        /// ```
3585        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3586        /// ```
3587        #[stable(feature = "isqrt", since = "1.84.0")]
3588        #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3589        #[must_use = "this returns the result of the operation, \
3590                      without modifying the original"]
3591        #[inline]
3592        pub const fn isqrt(self) -> Self {
3593            let result = imp::int_sqrt::$ActualT(self as $ActualT) as $SelfT;
3594
3595            // Inform the optimizer what the range of outputs is. If testing
3596            // `core` crashes with no panic message and a `num::int_sqrt::u*`
3597            // test failed, it's because your edits caused these assertions or
3598            // the assertions in `fn isqrt` of `nonzero.rs` to become false.
3599            //
3600            // SAFETY: Integer square root is a monotonically nondecreasing
3601            // function, which means that increasing the input will never
3602            // cause the output to decrease. Thus, since the input for unsigned
3603            // integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be
3604            // bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
3605            unsafe {
3606                const MAX_RESULT: $SelfT = imp::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT;
3607                crate::hint::assert_unchecked(result <= MAX_RESULT);
3608            }
3609
3610            result
3611        }
3612
3613        /// Performs Euclidean division.
3614        ///
3615        /// Since, for the positive integers, all common
3616        /// definitions of division are equal, this
3617        /// is exactly equal to `self / rhs`.
3618        ///
3619        /// # Panics
3620        ///
3621        /// This function will panic if `rhs` is zero.
3622        ///
3623        /// # Examples
3624        ///
3625        /// ```
3626        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
3627        /// ```
3628        #[stable(feature = "euclidean_division", since = "1.38.0")]
3629        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3630        #[must_use = "this returns the result of the operation, \
3631                      without modifying the original"]
3632        #[inline(always)]
3633        #[track_caller]
3634        pub const fn div_euclid(self, rhs: Self) -> Self {
3635            self / rhs
3636        }
3637
3638
3639        /// Calculates the least remainder of `self` when divided by
3640        /// `rhs`.
3641        ///
3642        /// Since, for the positive integers, all common
3643        /// definitions of division are equal, this
3644        /// is exactly equal to `self % rhs`.
3645        ///
3646        /// # Panics
3647        ///
3648        /// This function will panic if `rhs` is zero.
3649        ///
3650        /// # Examples
3651        ///
3652        /// ```
3653        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
3654        /// ```
3655        #[doc(alias = "modulo", alias = "mod")]
3656        #[stable(feature = "euclidean_division", since = "1.38.0")]
3657        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3658        #[must_use = "this returns the result of the operation, \
3659                      without modifying the original"]
3660        #[inline(always)]
3661        #[track_caller]
3662        pub const fn rem_euclid(self, rhs: Self) -> Self {
3663            self % rhs
3664        }
3665
3666        /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3667        ///
3668        /// This is the same as performing `self / rhs` for all unsigned integers.
3669        ///
3670        /// # Panics
3671        ///
3672        /// This function will panic if `rhs` is zero.
3673        ///
3674        /// # Examples
3675        ///
3676        /// ```
3677        /// #![feature(int_roundings)]
3678        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
3679        /// ```
3680        #[unstable(feature = "int_roundings", issue = "88581")]
3681        #[must_use = "this returns the result of the operation, \
3682                      without modifying the original"]
3683        #[inline(always)]
3684        #[track_caller]
3685        pub const fn div_floor(self, rhs: Self) -> Self {
3686            self / rhs
3687        }
3688
3689        /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3690        ///
3691        /// # Panics
3692        ///
3693        /// This function will panic if `rhs` is zero.
3694        ///
3695        /// # Examples
3696        ///
3697        /// ```
3698        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
3699        /// ```
3700        #[stable(feature = "int_roundings1", since = "1.73.0")]
3701        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3702        #[must_use = "this returns the result of the operation, \
3703                      without modifying the original"]
3704        #[inline]
3705        #[track_caller]
3706        pub const fn div_ceil(self, rhs: Self) -> Self {
3707            let d = self / rhs;
3708            let r = self % rhs;
3709            if r > 0 {
3710                d + 1
3711            } else {
3712                d
3713            }
3714        }
3715
3716        /// Calculates the smallest value greater than or equal to `self` that
3717        /// is a multiple of `rhs`.
3718        ///
3719        /// # Panics
3720        ///
3721        /// This function will panic if `rhs` is zero.
3722        ///
3723        /// ## Overflow behavior
3724        ///
3725        /// On overflow, this function will panic if overflow checks are enabled (default in debug
3726        /// mode) and wrap if overflow checks are disabled (default in release mode).
3727        ///
3728        /// # Examples
3729        ///
3730        /// ```
3731        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3732        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3733        /// ```
3734        #[stable(feature = "int_roundings1", since = "1.73.0")]
3735        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3736        #[must_use = "this returns the result of the operation, \
3737                      without modifying the original"]
3738        #[inline]
3739        #[rustc_inherit_overflow_checks]
3740        pub const fn next_multiple_of(self, rhs: Self) -> Self {
3741            match self % rhs {
3742                0 => self,
3743                r => self + (rhs - r)
3744            }
3745        }
3746
3747        /// Calculates the smallest value greater than or equal to `self` that
3748        /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the
3749        /// operation would result in overflow.
3750        ///
3751        /// # Examples
3752        ///
3753        /// ```
3754        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3755        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3756        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3757        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3758        /// ```
3759        #[stable(feature = "int_roundings1", since = "1.73.0")]
3760        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3761        #[must_use = "this returns the result of the operation, \
3762                      without modifying the original"]
3763        #[inline]
3764        pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3765            match try_opt!(self.checked_rem(rhs)) {
3766                0 => Some(self),
3767                // rhs - r cannot overflow because r is smaller than rhs
3768                r => self.checked_add(rhs - r)
3769            }
3770        }
3771
3772        /// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise.
3773        ///
3774        /// This function is equivalent to `self % rhs == 0`, except that it will not panic
3775        /// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`,
3776        /// `n.is_multiple_of(0) == false`.
3777        ///
3778        /// # Examples
3779        ///
3780        /// ```
3781        #[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")]
3782        #[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")]
3783        ///
3784        #[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")]
3785        #[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")]
3786        /// ```
3787        #[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3788        #[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3789        #[must_use]
3790        #[inline]
3791        pub const fn is_multiple_of(self, rhs: Self) -> bool {
3792            match rhs {
3793                0 => self == 0,
3794                _ => self % rhs == 0,
3795            }
3796        }
3797
3798        /// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`.
3799        ///
3800        /// # Examples
3801        ///
3802        /// ```
3803        #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
3804        #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
3805        /// ```
3806        #[must_use]
3807        #[stable(feature = "rust1", since = "1.0.0")]
3808        #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
3809        #[inline(always)]
3810        pub const fn is_power_of_two(self) -> bool {
3811            self.count_ones() == 1
3812        }
3813
3814        // Returns one less than next power of two.
3815        // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8)
3816        //
3817        // 8u8.one_less_than_next_power_of_two() == 7
3818        // 6u8.one_less_than_next_power_of_two() == 7
3819        //
3820        // This method cannot overflow, as in the `next_power_of_two`
3821        // overflow cases it instead ends up returning the maximum value
3822        // of the type, and can return 0 for 0.
3823        #[inline]
3824        const fn one_less_than_next_power_of_two(self) -> Self {
3825            if self <= 1 { return 0; }
3826
3827            let p = self - 1;
3828            // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros.
3829            // That means the shift is always in-bounds, and some processors
3830            // (such as intel pre-haswell) have more efficient ctlz
3831            // intrinsics when the argument is non-zero.
3832            let z = unsafe { intrinsics::ctlz_nonzero(p) };
3833            <$SelfT>::MAX >> z
3834        }
3835
3836        /// Returns the smallest power of two greater than or equal to `self`.
3837        ///
3838        /// When return value overflows (i.e., `self > (1 << (N-1))` for type
3839        /// `uN`), it panics in debug mode and the return value is wrapped to 0 in
3840        /// release mode (the only situation in which this method can return 0).
3841        ///
3842        /// # Examples
3843        ///
3844        /// ```
3845        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
3846        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
3847        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")]
3848        /// ```
3849        #[stable(feature = "rust1", since = "1.0.0")]
3850        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3851        #[must_use = "this returns the result of the operation, \
3852                      without modifying the original"]
3853        #[inline]
3854        #[rustc_inherit_overflow_checks]
3855        pub const fn next_power_of_two(self) -> Self {
3856            self.one_less_than_next_power_of_two() + 1
3857        }
3858
3859        /// Returns the smallest power of two greater than or equal to `self`. If
3860        /// the next power of two is greater than the type's maximum value,
3861        /// `None` is returned, otherwise the power of two is wrapped in `Some`.
3862        ///
3863        /// # Examples
3864        ///
3865        /// ```
3866        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
3867        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
3868        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
3869        /// ```
3870        #[inline]
3871        #[stable(feature = "rust1", since = "1.0.0")]
3872        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3873        #[must_use = "this returns the result of the operation, \
3874                      without modifying the original"]
3875        pub const fn checked_next_power_of_two(self) -> Option<Self> {
3876            self.one_less_than_next_power_of_two().checked_add(1)
3877        }
3878
3879        /// Returns the smallest power of two greater than or equal to `n`. If
3880        /// the next power of two is greater than the type's maximum value,
3881        /// the return value is wrapped to `0`.
3882        ///
3883        /// # Examples
3884        ///
3885        /// ```
3886        /// #![feature(wrapping_next_power_of_two)]
3887        ///
3888        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
3889        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
3890        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
3891        /// ```
3892        #[inline]
3893        #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
3894                   reason = "needs decision on wrapping behavior")]
3895        #[must_use = "this returns the result of the operation, \
3896                      without modifying the original"]
3897        pub const fn wrapping_next_power_of_two(self) -> Self {
3898            self.one_less_than_next_power_of_two().wrapping_add(1)
3899        }
3900
3901        /// Returns the memory representation of this integer as a byte array in
3902        /// big-endian (network) byte order.
3903        ///
3904        #[doc = $to_xe_bytes_doc]
3905        ///
3906        /// # Examples
3907        ///
3908        /// ```
3909        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3910        #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3911        /// ```
3912        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3913        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3914        #[must_use = "this returns the result of the operation, \
3915                      without modifying the original"]
3916        #[inline]
3917        pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3918            self.to_be().to_ne_bytes()
3919        }
3920
3921        /// Returns the memory representation of this integer as a byte array in
3922        /// little-endian byte order.
3923        ///
3924        #[doc = $to_xe_bytes_doc]
3925        ///
3926        /// # Examples
3927        ///
3928        /// ```
3929        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3930        #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3931        /// ```
3932        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3933        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3934        #[must_use = "this returns the result of the operation, \
3935                      without modifying the original"]
3936        #[inline]
3937        pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3938            self.to_le().to_ne_bytes()
3939        }
3940
3941        /// Returns the memory representation of this integer as a byte array in
3942        /// native byte order.
3943        ///
3944        /// As the target platform's native endianness is used, portable code
3945        /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3946        /// instead.
3947        ///
3948        #[doc = $to_xe_bytes_doc]
3949        ///
3950        /// [`to_be_bytes`]: Self::to_be_bytes
3951        /// [`to_le_bytes`]: Self::to_le_bytes
3952        ///
3953        /// # Examples
3954        ///
3955        /// ```
3956        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3957        /// assert_eq!(
3958        ///     bytes,
3959        ///     if cfg!(target_endian = "big") {
3960        #[doc = concat!("        ", $be_bytes)]
3961        ///     } else {
3962        #[doc = concat!("        ", $le_bytes)]
3963        ///     }
3964        /// );
3965        /// ```
3966        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3967        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3968        #[must_use = "this returns the result of the operation, \
3969                      without modifying the original"]
3970        #[allow(unnecessary_transmutes)]
3971        // SAFETY: const sound because integers are plain old datatypes so we can always
3972        // transmute them to arrays of bytes
3973        #[inline]
3974        pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3975            // SAFETY: integers are plain old datatypes so we can always transmute them to
3976            // arrays of bytes
3977            unsafe { mem::transmute(self) }
3978        }
3979
3980        /// Creates a native endian integer value from its representation
3981        /// as a byte array in big endian.
3982        ///
3983        #[doc = $from_xe_bytes_doc]
3984        ///
3985        /// # Examples
3986        ///
3987        /// ```
3988        #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3989        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3990        /// ```
3991        ///
3992        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3993        ///
3994        /// ```
3995        #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3996        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3997        ///     *input = rest;
3998        #[doc = concat!("    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3999        /// }
4000        /// ```
4001        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
4002        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
4003        #[must_use]
4004        #[inline]
4005        pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
4006            Self::from_be(Self::from_ne_bytes(bytes))
4007        }
4008
4009        /// Creates a native endian integer value from its representation
4010        /// as a byte array in little endian.
4011        ///
4012        #[doc = $from_xe_bytes_doc]
4013        ///
4014        /// # Examples
4015        ///
4016        /// ```
4017        #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
4018        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
4019        /// ```
4020        ///
4021        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
4022        ///
4023        /// ```
4024        #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
4025        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
4026        ///     *input = rest;
4027        #[doc = concat!("    ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
4028        /// }
4029        /// ```
4030        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
4031        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
4032        #[must_use]
4033        #[inline]
4034        pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
4035            Self::from_le(Self::from_ne_bytes(bytes))
4036        }
4037
4038        /// Creates a native endian integer value from its memory representation
4039        /// as a byte array in native endianness.
4040        ///
4041        /// As the target platform's native endianness is used, portable code
4042        /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
4043        /// appropriate instead.
4044        ///
4045        /// [`from_be_bytes`]: Self::from_be_bytes
4046        /// [`from_le_bytes`]: Self::from_le_bytes
4047        ///
4048        #[doc = $from_xe_bytes_doc]
4049        ///
4050        /// # Examples
4051        ///
4052        /// ```
4053        #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
4054        #[doc = concat!("    ", $be_bytes, "")]
4055        /// } else {
4056        #[doc = concat!("    ", $le_bytes, "")]
4057        /// });
4058        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
4059        /// ```
4060        ///
4061        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
4062        ///
4063        /// ```
4064        #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
4065        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
4066        ///     *input = rest;
4067        #[doc = concat!("    ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
4068        /// }
4069        /// ```
4070        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
4071        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
4072        #[allow(unnecessary_transmutes)]
4073        #[must_use]
4074        // SAFETY: const sound because integers are plain old datatypes so we can always
4075        // transmute to them
4076        #[inline]
4077        pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
4078            // SAFETY: integers are plain old datatypes so we can always transmute to them
4079            unsafe { mem::transmute(bytes) }
4080        }
4081
4082        /// New code should prefer to use
4083        #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
4084        ///
4085        /// Returns the smallest value that can be represented by this integer type.
4086        #[stable(feature = "rust1", since = "1.0.0")]
4087        #[rustc_promotable]
4088        #[inline(always)]
4089        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
4090        #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
4091        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
4092        pub const fn min_value() -> Self { Self::MIN }
4093
4094        /// New code should prefer to use
4095        #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
4096        ///
4097        /// Returns the largest value that can be represented by this integer type.
4098        #[stable(feature = "rust1", since = "1.0.0")]
4099        #[rustc_promotable]
4100        #[inline(always)]
4101        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
4102        #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
4103        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
4104        pub const fn max_value() -> Self { Self::MAX }
4105
4106        /// Truncate an integer to an integer of the same size or smaller, preserving the least
4107        /// significant bits.
4108        ///
4109        /// # Examples
4110        ///
4111        /// ```
4112        /// #![feature(integer_extend_truncate)]
4113        #[doc = concat!("assert_eq!(120u8, 120", stringify!($SelfT), ".truncate());")]
4114        /// assert_eq!(120u8, 376u32.truncate());
4115        /// ```
4116        #[must_use = "this returns the truncated value and does not modify the original"]
4117        #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4118        #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4119        #[inline]
4120        pub const fn truncate<Target>(self) -> Target
4121            where Self: [const] traits::TruncateTarget<Target>
4122        {
4123            traits::TruncateTarget::internal_truncate(self)
4124        }
4125
4126        /// Truncate an integer to an integer of the same size or smaller, saturating at numeric bounds
4127        /// instead of truncating.
4128        ///
4129        /// # Examples
4130        ///
4131        /// ```
4132        /// #![feature(integer_extend_truncate)]
4133        #[doc = concat!("assert_eq!(120u8, 120", stringify!($SelfT), ".saturating_truncate());")]
4134        /// assert_eq!(255u8, 376u32.saturating_truncate());
4135        /// ```
4136        #[must_use = "this returns the truncated value and does not modify the original"]
4137        #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4138        #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4139        #[inline]
4140        pub const fn saturating_truncate<Target>(self) -> Target
4141            where Self: [const] traits::TruncateTarget<Target>
4142        {
4143            traits::TruncateTarget::internal_saturating_truncate(self)
4144        }
4145
4146        /// Truncate an integer to an integer of the same size or smaller, returning `None` if the value
4147        /// is outside the bounds of the smaller type.
4148        ///
4149        /// # Examples
4150        ///
4151        /// ```
4152        /// #![feature(integer_extend_truncate)]
4153        #[doc = concat!("assert_eq!(Some(120u8), 120", stringify!($SelfT), ".checked_truncate());")]
4154        /// assert_eq!(None, 376u32.checked_truncate::<u8>());
4155        /// ```
4156        #[must_use = "this returns the truncated value and does not modify the original"]
4157        #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4158        #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4159        #[inline]
4160        pub const fn checked_truncate<Target>(self) -> Option<Target>
4161            where Self: [const] traits::TruncateTarget<Target>
4162        {
4163            traits::TruncateTarget::internal_checked_truncate(self)
4164        }
4165
4166        /// Extend to an integer of the same size or larger, preserving its value.
4167        ///
4168        /// # Examples
4169        ///
4170        /// ```
4171        /// #![feature(integer_extend_truncate)]
4172        #[doc = concat!("assert_eq!(120u128, 120u8.extend());")]
4173        /// ```
4174        #[must_use = "this returns the extended value and does not modify the original"]
4175        #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4176        #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4177        #[inline]
4178        pub const fn extend<Target>(self) -> Target
4179            where Self: [const] traits::ExtendTarget<Target>
4180        {
4181            traits::ExtendTarget::internal_extend(self)
4182        }
4183    }
4184}