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core/num/
f32.rs

1//! Constants for the `f32` single-precision floating point type.
2//!
3//! *[See also the `f32` primitive type][f32].*
4//!
5//! Mathematically significant numbers are provided in the `consts` sub-module.
6//!
7//! For the constants defined directly in this module
8//! (as distinct from those defined in the `consts` sub-module),
9//! new code should instead use the associated constants
10//! defined directly on the `f32` type.
11
12#![stable(feature = "rust1", since = "1.0.0")]
13
14use crate::convert::FloatToInt;
15use crate::num::FpCategory;
16use crate::panic::const_assert;
17use crate::{cfg_select, intrinsics, mem};
18
19/// The radix or base of the internal representation of `f32`.
20/// Use [`f32::RADIX`] instead.
21///
22/// # Examples
23///
24/// ```rust
25/// // deprecated way
26/// # #[allow(deprecated, deprecated_in_future)]
27/// let r = std::f32::RADIX;
28///
29/// // intended way
30/// let r = f32::RADIX;
31/// ```
32#[stable(feature = "rust1", since = "1.0.0")]
33#[deprecated(since = "TBD", note = "replaced by the `RADIX` associated constant on `f32`")]
34#[rustc_diagnostic_item = "f32_legacy_const_radix"]
35pub const RADIX: u32 = f32::RADIX;
36
37/// Number of significant digits in base 2.
38/// Use [`f32::MANTISSA_DIGITS`] instead.
39///
40/// # Examples
41///
42/// ```rust
43/// // deprecated way
44/// # #[allow(deprecated, deprecated_in_future)]
45/// let d = std::f32::MANTISSA_DIGITS;
46///
47/// // intended way
48/// let d = f32::MANTISSA_DIGITS;
49/// ```
50#[stable(feature = "rust1", since = "1.0.0")]
51#[deprecated(
52    since = "TBD",
53    note = "replaced by the `MANTISSA_DIGITS` associated constant on `f32`"
54)]
55#[rustc_diagnostic_item = "f32_legacy_const_mantissa_dig"]
56pub const MANTISSA_DIGITS: u32 = f32::MANTISSA_DIGITS;
57
58/// Approximate number of significant digits in base 10.
59/// Use [`f32::DIGITS`] instead.
60///
61/// # Examples
62///
63/// ```rust
64/// // deprecated way
65/// # #[allow(deprecated, deprecated_in_future)]
66/// let d = std::f32::DIGITS;
67///
68/// // intended way
69/// let d = f32::DIGITS;
70/// ```
71#[stable(feature = "rust1", since = "1.0.0")]
72#[deprecated(since = "TBD", note = "replaced by the `DIGITS` associated constant on `f32`")]
73#[rustc_diagnostic_item = "f32_legacy_const_digits"]
74pub const DIGITS: u32 = f32::DIGITS;
75
76/// [Machine epsilon] value for `f32`.
77/// Use [`f32::EPSILON`] instead.
78///
79/// This is the difference between `1.0` and the next larger representable number.
80///
81/// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
82///
83/// # Examples
84///
85/// ```rust
86/// // deprecated way
87/// # #[allow(deprecated, deprecated_in_future)]
88/// let e = std::f32::EPSILON;
89///
90/// // intended way
91/// let e = f32::EPSILON;
92/// ```
93#[stable(feature = "rust1", since = "1.0.0")]
94#[deprecated(since = "TBD", note = "replaced by the `EPSILON` associated constant on `f32`")]
95#[rustc_diagnostic_item = "f32_legacy_const_epsilon"]
96pub const EPSILON: f32 = f32::EPSILON;
97
98/// Smallest finite `f32` value.
99/// Use [`f32::MIN`] instead.
100///
101/// # Examples
102///
103/// ```rust
104/// // deprecated way
105/// # #[allow(deprecated, deprecated_in_future)]
106/// let min = std::f32::MIN;
107///
108/// // intended way
109/// let min = f32::MIN;
110/// ```
111#[stable(feature = "rust1", since = "1.0.0")]
112#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on `f32`")]
113#[rustc_diagnostic_item = "f32_legacy_const_min"]
114pub const MIN: f32 = f32::MIN;
115
116/// Smallest positive normal `f32` value.
117/// Use [`f32::MIN_POSITIVE`] instead.
118///
119/// # Examples
120///
121/// ```rust
122/// // deprecated way
123/// # #[allow(deprecated, deprecated_in_future)]
124/// let min = std::f32::MIN_POSITIVE;
125///
126/// // intended way
127/// let min = f32::MIN_POSITIVE;
128/// ```
129#[stable(feature = "rust1", since = "1.0.0")]
130#[deprecated(since = "TBD", note = "replaced by the `MIN_POSITIVE` associated constant on `f32`")]
131#[rustc_diagnostic_item = "f32_legacy_const_min_positive"]
132pub const MIN_POSITIVE: f32 = f32::MIN_POSITIVE;
133
134/// Largest finite `f32` value.
135/// Use [`f32::MAX`] instead.
136///
137/// # Examples
138///
139/// ```rust
140/// // deprecated way
141/// # #[allow(deprecated, deprecated_in_future)]
142/// let max = std::f32::MAX;
143///
144/// // intended way
145/// let max = f32::MAX;
146/// ```
147#[stable(feature = "rust1", since = "1.0.0")]
148#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on `f32`")]
149#[rustc_diagnostic_item = "f32_legacy_const_max"]
150pub const MAX: f32 = f32::MAX;
151
152/// One greater than the minimum possible normal power of 2 exponent.
153/// Use [`f32::MIN_EXP`] instead.
154///
155/// # Examples
156///
157/// ```rust
158/// // deprecated way
159/// # #[allow(deprecated, deprecated_in_future)]
160/// let min = std::f32::MIN_EXP;
161///
162/// // intended way
163/// let min = f32::MIN_EXP;
164/// ```
165#[stable(feature = "rust1", since = "1.0.0")]
166#[deprecated(since = "TBD", note = "replaced by the `MIN_EXP` associated constant on `f32`")]
167#[rustc_diagnostic_item = "f32_legacy_const_min_exp"]
168pub const MIN_EXP: i32 = f32::MIN_EXP;
169
170/// Maximum possible power of 2 exponent.
171/// Use [`f32::MAX_EXP`] instead.
172///
173/// # Examples
174///
175/// ```rust
176/// // deprecated way
177/// # #[allow(deprecated, deprecated_in_future)]
178/// let max = std::f32::MAX_EXP;
179///
180/// // intended way
181/// let max = f32::MAX_EXP;
182/// ```
183#[stable(feature = "rust1", since = "1.0.0")]
184#[deprecated(since = "TBD", note = "replaced by the `MAX_EXP` associated constant on `f32`")]
185#[rustc_diagnostic_item = "f32_legacy_const_max_exp"]
186pub const MAX_EXP: i32 = f32::MAX_EXP;
187
188/// Minimum possible normal power of 10 exponent.
189/// Use [`f32::MIN_10_EXP`] instead.
190///
191/// # Examples
192///
193/// ```rust
194/// // deprecated way
195/// # #[allow(deprecated, deprecated_in_future)]
196/// let min = std::f32::MIN_10_EXP;
197///
198/// // intended way
199/// let min = f32::MIN_10_EXP;
200/// ```
201#[stable(feature = "rust1", since = "1.0.0")]
202#[deprecated(since = "TBD", note = "replaced by the `MIN_10_EXP` associated constant on `f32`")]
203#[rustc_diagnostic_item = "f32_legacy_const_min_10_exp"]
204pub const MIN_10_EXP: i32 = f32::MIN_10_EXP;
205
206/// Maximum possible power of 10 exponent.
207/// Use [`f32::MAX_10_EXP`] instead.
208///
209/// # Examples
210///
211/// ```rust
212/// // deprecated way
213/// # #[allow(deprecated, deprecated_in_future)]
214/// let max = std::f32::MAX_10_EXP;
215///
216/// // intended way
217/// let max = f32::MAX_10_EXP;
218/// ```
219#[stable(feature = "rust1", since = "1.0.0")]
220#[deprecated(since = "TBD", note = "replaced by the `MAX_10_EXP` associated constant on `f32`")]
221#[rustc_diagnostic_item = "f32_legacy_const_max_10_exp"]
222pub const MAX_10_EXP: i32 = f32::MAX_10_EXP;
223
224/// Not a Number (NaN).
225/// Use [`f32::NAN`] instead.
226///
227/// # Examples
228///
229/// ```rust
230/// // deprecated way
231/// # #[allow(deprecated, deprecated_in_future)]
232/// let nan = std::f32::NAN;
233///
234/// // intended way
235/// let nan = f32::NAN;
236/// ```
237#[stable(feature = "rust1", since = "1.0.0")]
238#[deprecated(since = "TBD", note = "replaced by the `NAN` associated constant on `f32`")]
239#[rustc_diagnostic_item = "f32_legacy_const_nan"]
240pub const NAN: f32 = f32::NAN;
241
242/// Infinity (∞).
243/// Use [`f32::INFINITY`] instead.
244///
245/// # Examples
246///
247/// ```rust
248/// // deprecated way
249/// # #[allow(deprecated, deprecated_in_future)]
250/// let inf = std::f32::INFINITY;
251///
252/// // intended way
253/// let inf = f32::INFINITY;
254/// ```
255#[stable(feature = "rust1", since = "1.0.0")]
256#[deprecated(since = "TBD", note = "replaced by the `INFINITY` associated constant on `f32`")]
257#[rustc_diagnostic_item = "f32_legacy_const_infinity"]
258pub const INFINITY: f32 = f32::INFINITY;
259
260/// Negative infinity (−∞).
261/// Use [`f32::NEG_INFINITY`] instead.
262///
263/// # Examples
264///
265/// ```rust
266/// // deprecated way
267/// # #[allow(deprecated, deprecated_in_future)]
268/// let ninf = std::f32::NEG_INFINITY;
269///
270/// // intended way
271/// let ninf = f32::NEG_INFINITY;
272/// ```
273#[stable(feature = "rust1", since = "1.0.0")]
274#[deprecated(since = "TBD", note = "replaced by the `NEG_INFINITY` associated constant on `f32`")]
275#[rustc_diagnostic_item = "f32_legacy_const_neg_infinity"]
276pub const NEG_INFINITY: f32 = f32::NEG_INFINITY;
277
278/// Basic mathematical constants.
279#[stable(feature = "rust1", since = "1.0.0")]
280#[rustc_diagnostic_item = "f32_consts_mod"]
281pub mod consts {
282    // FIXME: replace with mathematical constants from cmath.
283
284    /// Archimedes' constant (π)
285    #[stable(feature = "rust1", since = "1.0.0")]
286    pub const PI: f32 = 3.14159265358979323846264338327950288_f32;
287
288    /// The full circle constant (τ)
289    ///
290    /// Equal to 2π.
291    #[stable(feature = "tau_constant", since = "1.47.0")]
292    pub const TAU: f32 = 6.28318530717958647692528676655900577_f32;
293
294    /// The golden ratio (φ)
295    #[doc(alias = "phi")]
296    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
297    pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32;
298
299    /// The Euler-Mascheroni constant (γ)
300    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
301    pub const EULER_GAMMA: f32 = 0.577215664901532860606512090082402431_f32;
302
303    /// π/2
304    #[stable(feature = "rust1", since = "1.0.0")]
305    pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32;
306
307    /// π/3
308    #[stable(feature = "rust1", since = "1.0.0")]
309    pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32;
310
311    /// π/4
312    #[stable(feature = "rust1", since = "1.0.0")]
313    pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32;
314
315    /// π/6
316    #[stable(feature = "rust1", since = "1.0.0")]
317    pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32;
318
319    /// π/8
320    #[stable(feature = "rust1", since = "1.0.0")]
321    pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32;
322
323    /// 1/π
324    #[stable(feature = "rust1", since = "1.0.0")]
325    pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
326
327    /// 1/sqrt(π)
328    #[unstable(feature = "more_float_constants", issue = "146939")]
329    pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
330
331    /// 1/sqrt(2π)
332    #[doc(alias = "FRAC_1_SQRT_TAU")]
333    #[unstable(feature = "more_float_constants", issue = "146939")]
334    pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
335
336    /// 2/π
337    #[stable(feature = "rust1", since = "1.0.0")]
338    pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32;
339
340    /// 2/sqrt(π)
341    #[stable(feature = "rust1", since = "1.0.0")]
342    pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32;
343
344    /// sqrt(2)
345    #[stable(feature = "rust1", since = "1.0.0")]
346    pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32;
347
348    /// 1/sqrt(2)
349    #[stable(feature = "rust1", since = "1.0.0")]
350    pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
351
352    /// sqrt(3)
353    #[unstable(feature = "more_float_constants", issue = "146939")]
354    pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
355
356    /// 1/sqrt(3)
357    #[unstable(feature = "more_float_constants", issue = "146939")]
358    pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
359
360    /// sqrt(5)
361    #[unstable(feature = "more_float_constants", issue = "146939")]
362    pub const SQRT_5: f32 = 2.23606797749978969640917366873127623_f32;
363
364    /// 1/sqrt(5)
365    #[unstable(feature = "more_float_constants", issue = "146939")]
366    pub const FRAC_1_SQRT_5: f32 = 0.44721359549995793928183473374625524_f32;
367
368    /// Euler's number (e)
369    #[stable(feature = "rust1", since = "1.0.0")]
370    pub const E: f32 = 2.71828182845904523536028747135266250_f32;
371
372    /// log<sub>2</sub>(e)
373    #[stable(feature = "rust1", since = "1.0.0")]
374    pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
375
376    /// log<sub>2</sub>(10)
377    #[stable(feature = "extra_log_consts", since = "1.43.0")]
378    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
379
380    /// log<sub>10</sub>(e)
381    #[stable(feature = "rust1", since = "1.0.0")]
382    pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
383
384    /// log<sub>10</sub>(2)
385    #[stable(feature = "extra_log_consts", since = "1.43.0")]
386    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
387
388    /// ln(2)
389    #[stable(feature = "rust1", since = "1.0.0")]
390    pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;
391
392    /// ln(10)
393    #[stable(feature = "rust1", since = "1.0.0")]
394    pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
395}
396
397#[doc(test(attr(allow(unused_features))))]
398impl f32 {
399    /// The radix or base of the internal representation of `f32`.
400    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
401    pub const RADIX: u32 = 2;
402
403    /// The size of this float type in bits.
404    #[unstable(feature = "float_bits_const", issue = "151073")]
405    pub const BITS: u32 = 32;
406
407    /// Number of significant digits in base 2.
408    ///
409    /// Note that the size of the mantissa in the bitwise representation is one
410    /// smaller than this since the leading 1 is not stored explicitly.
411    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
412    pub const MANTISSA_DIGITS: u32 = 24;
413
414    /// Approximate number of significant digits in base 10.
415    ///
416    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
417    /// significant digits can be converted to `f32` and back without loss.
418    ///
419    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
420    ///
421    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
422    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
423    pub const DIGITS: u32 = 6;
424
425    /// [Machine epsilon] value for `f32`.
426    ///
427    /// This is the difference between `1.0` and the next larger representable number.
428    ///
429    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
430    ///
431    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
432    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
433    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
434    #[rustc_diagnostic_item = "f32_epsilon"]
435    pub const EPSILON: f32 = 1.19209290e-07_f32;
436
437    /// Smallest finite `f32` value.
438    ///
439    /// Equal to &minus;[`MAX`].
440    ///
441    /// [`MAX`]: f32::MAX
442    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
443    pub const MIN: f32 = -3.40282347e+38_f32;
444    /// Smallest positive normal `f32` value.
445    ///
446    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
447    ///
448    /// [`MIN_EXP`]: f32::MIN_EXP
449    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
450    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
451    /// Largest finite `f32` value.
452    ///
453    /// Equal to
454    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
455    ///
456    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
457    /// [`MAX_EXP`]: f32::MAX_EXP
458    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
459    pub const MAX: f32 = 3.40282347e+38_f32;
460
461    /// One greater than the minimum possible *normal* power of 2 exponent
462    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
463    ///
464    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
465    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
466    /// In other words, all normal numbers representable by this type are
467    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
468    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
469    pub const MIN_EXP: i32 = -125;
470    /// One greater than the maximum possible power of 2 exponent
471    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
472    ///
473    /// This corresponds to the exact maximum possible power of 2 exponent
474    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
475    /// In other words, all numbers representable by this type are
476    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
477    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
478    pub const MAX_EXP: i32 = 128;
479
480    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
481    ///
482    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
483    ///
484    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
485    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
486    pub const MIN_10_EXP: i32 = -37;
487    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
488    ///
489    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
490    ///
491    /// [`MAX`]: f32::MAX
492    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
493    pub const MAX_10_EXP: i32 = 38;
494
495    /// Not a Number (NaN).
496    ///
497    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
498    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
499    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
500    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
501    /// info.
502    ///
503    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
504    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
505    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
506    /// The concrete bit pattern may change across Rust versions and target platforms.
507    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
508    #[rustc_diagnostic_item = "f32_nan"]
509    #[allow(clippy::eq_op)]
510    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
511    /// Infinity (∞).
512    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
513    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
514    /// Negative infinity (−∞).
515    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
516    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
517
518    /// Maximum integer that can be represented exactly in an [`f32`] value,
519    /// with no other integer converting to the same floating point value.
520    ///
521    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
522    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
523    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
524    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
525    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
526    /// "one-to-one" mapping.
527    ///
528    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
529    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
530    /// ```
531    /// #![feature(float_exact_integer_constants)]
532    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
533    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
534    /// let max_exact_int = f32::MAX_EXACT_INTEGER;
535    /// assert_eq!(max_exact_int, max_exact_int as f32 as i32);
536    /// assert_eq!(max_exact_int + 1, (max_exact_int + 1) as f32 as i32);
537    /// assert_ne!(max_exact_int + 2, (max_exact_int + 2) as f32 as i32);
538    ///
539    /// // Beyond `f32::MAX_EXACT_INTEGER`, multiple integers can map to one float value
540    /// assert_eq!((max_exact_int + 1) as f32, (max_exact_int + 2) as f32);
541    /// # }
542    /// ```
543    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
544    pub const MAX_EXACT_INTEGER: i32 = (1 << Self::MANTISSA_DIGITS) - 1;
545
546    /// Minimum integer that can be represented exactly in an [`f32`] value,
547    /// with no other integer converting to the same floating point value.
548    ///
549    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
550    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
551    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
552    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
553    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
554    /// "one-to-one" mapping.
555    ///
556    /// This constant is equivalent to `-MAX_EXACT_INTEGER`.
557    ///
558    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
559    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
560    /// ```
561    /// #![feature(float_exact_integer_constants)]
562    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
563    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
564    /// let min_exact_int = f32::MIN_EXACT_INTEGER;
565    /// assert_eq!(min_exact_int, min_exact_int as f32 as i32);
566    /// assert_eq!(min_exact_int - 1, (min_exact_int - 1) as f32 as i32);
567    /// assert_ne!(min_exact_int - 2, (min_exact_int - 2) as f32 as i32);
568    ///
569    /// // Below `f32::MIN_EXACT_INTEGER`, multiple integers can map to one float value
570    /// assert_eq!((min_exact_int - 1) as f32, (min_exact_int - 2) as f32);
571    /// # }
572    /// ```
573    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
574    pub const MIN_EXACT_INTEGER: i32 = -Self::MAX_EXACT_INTEGER;
575
576    /// The mask of the bit used to encode the sign of an [`f32`].
577    ///
578    /// This bit is set when the sign is negative and unset when the sign is
579    /// positive.
580    /// If you only need to check whether a value is positive or negative,
581    /// [`is_sign_positive`] or [`is_sign_negative`] can be used.
582    ///
583    /// [`is_sign_positive`]: f32::is_sign_positive
584    /// [`is_sign_negative`]: f32::is_sign_negative
585    /// ```rust
586    /// #![feature(float_masks)]
587    /// let sign_mask = f32::SIGN_MASK;
588    /// let a = 1.6552f32;
589    /// let a_bits = a.to_bits();
590    ///
591    /// assert_eq!(a_bits & sign_mask, 0x0);
592    /// assert_eq!(f32::from_bits(a_bits ^ sign_mask), -a);
593    /// assert_eq!(sign_mask, (-0.0f32).to_bits());
594    /// ```
595    #[unstable(feature = "float_masks", issue = "154064")]
596    pub const SIGN_MASK: u32 = 0x8000_0000;
597
598    /// The mask of the bits used to encode the exponent of an [`f32`].
599    ///
600    /// Note that the exponent is stored as a biased value, with a bias of 127 for `f32`.
601    ///
602    /// ```rust
603    /// #![feature(float_masks)]
604    /// fn get_exp(a: f32) -> i32 {
605    ///     let bias = 127;
606    ///     let biased = a.to_bits() & f32::EXPONENT_MASK;
607    ///     (biased >> (f32::MANTISSA_DIGITS - 1)).cast_signed() - bias
608    /// }
609    ///
610    /// assert_eq!(get_exp(0.5), -1);
611    /// assert_eq!(get_exp(1.0), 0);
612    /// assert_eq!(get_exp(2.0), 1);
613    /// assert_eq!(get_exp(4.0), 2);
614    /// ```
615    #[unstable(feature = "float_masks", issue = "154064")]
616    pub const EXPONENT_MASK: u32 = 0x7f80_0000;
617
618    /// The mask of the bits used to encode the mantissa of an [`f32`].
619    ///
620    /// ```rust
621    /// #![feature(float_masks)]
622    /// let mantissa_mask = f32::MANTISSA_MASK;
623    ///
624    /// assert_eq!(0f32.to_bits() & mantissa_mask, 0x0);
625    /// assert_eq!(1f32.to_bits() & mantissa_mask, 0x0);
626    ///
627    /// // multiplying a finite value by a power of 2 doesn't change its mantissa
628    /// // unless the result or initial value is not normal.
629    /// let a = 1.6552f32;
630    /// let b = 4.0 * a;
631    /// assert_eq!(a.to_bits() & mantissa_mask, b.to_bits() & mantissa_mask);
632    ///
633    /// // The maximum and minimum values have a saturated significand
634    /// assert_eq!(f32::MAX.to_bits() & f32::MANTISSA_MASK, f32::MANTISSA_MASK);
635    /// assert_eq!(f32::MIN.to_bits() & f32::MANTISSA_MASK, f32::MANTISSA_MASK);
636    /// ```
637    #[unstable(feature = "float_masks", issue = "154064")]
638    pub const MANTISSA_MASK: u32 = 0x007f_ffff;
639
640    /// Minimum representable positive value (min subnormal)
641    const TINY_BITS: u32 = 0x1;
642
643    /// Minimum representable negative value (min negative subnormal)
644    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
645
646    /// Returns `true` if this value is NaN.
647    ///
648    /// ```
649    /// let nan = f32::NAN;
650    /// let f = 7.0_f32;
651    ///
652    /// assert!(nan.is_nan());
653    /// assert!(!f.is_nan());
654    /// ```
655    #[must_use]
656    #[stable(feature = "rust1", since = "1.0.0")]
657    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
658    #[inline]
659    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
660    pub const fn is_nan(self) -> bool {
661        self != self
662    }
663
664    /// Returns `true` if this value is positive infinity or negative infinity, and
665    /// `false` otherwise.
666    ///
667    /// ```
668    /// let f = 7.0f32;
669    /// let inf = f32::INFINITY;
670    /// let neg_inf = f32::NEG_INFINITY;
671    /// let nan = f32::NAN;
672    ///
673    /// assert!(!f.is_infinite());
674    /// assert!(!nan.is_infinite());
675    ///
676    /// assert!(inf.is_infinite());
677    /// assert!(neg_inf.is_infinite());
678    /// ```
679    #[must_use]
680    #[stable(feature = "rust1", since = "1.0.0")]
681    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
682    #[inline]
683    pub const fn is_infinite(self) -> bool {
684        // Getting clever with transmutation can result in incorrect answers on some FPUs
685        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
686        // See https://github.com/rust-lang/rust/issues/72327
687        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
688    }
689
690    /// Returns `true` if this number is neither infinite nor NaN.
691    ///
692    /// ```
693    /// let f = 7.0f32;
694    /// let inf = f32::INFINITY;
695    /// let neg_inf = f32::NEG_INFINITY;
696    /// let nan = f32::NAN;
697    ///
698    /// assert!(f.is_finite());
699    ///
700    /// assert!(!nan.is_finite());
701    /// assert!(!inf.is_finite());
702    /// assert!(!neg_inf.is_finite());
703    /// ```
704    #[must_use]
705    #[stable(feature = "rust1", since = "1.0.0")]
706    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
707    #[inline]
708    pub const fn is_finite(self) -> bool {
709        // There's no need to handle NaN separately: if self is NaN,
710        // the comparison is not true, exactly as desired.
711        self.abs() < Self::INFINITY
712    }
713
714    /// Returns `true` if the number is [subnormal].
715    ///
716    /// ```
717    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
718    /// let max = f32::MAX;
719    /// let lower_than_min = 1.0e-40_f32;
720    /// let zero = 0.0_f32;
721    ///
722    /// assert!(!min.is_subnormal());
723    /// assert!(!max.is_subnormal());
724    ///
725    /// assert!(!zero.is_subnormal());
726    /// assert!(!f32::NAN.is_subnormal());
727    /// assert!(!f32::INFINITY.is_subnormal());
728    /// // Values between `0` and `min` are Subnormal.
729    /// assert!(lower_than_min.is_subnormal());
730    /// ```
731    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
732    #[must_use]
733    #[stable(feature = "is_subnormal", since = "1.53.0")]
734    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
735    #[inline]
736    pub const fn is_subnormal(self) -> bool {
737        #[allow(non_exhaustive_omitted_patterns)] match self.classify() {
    FpCategory::Subnormal => true,
    _ => false,
}matches!(self.classify(), FpCategory::Subnormal)
738    }
739
740    /// Returns `true` if the number is neither zero, infinite,
741    /// [subnormal], or NaN.
742    ///
743    /// ```
744    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
745    /// let max = f32::MAX;
746    /// let lower_than_min = 1.0e-40_f32;
747    /// let zero = 0.0_f32;
748    ///
749    /// assert!(min.is_normal());
750    /// assert!(max.is_normal());
751    ///
752    /// assert!(!zero.is_normal());
753    /// assert!(!f32::NAN.is_normal());
754    /// assert!(!f32::INFINITY.is_normal());
755    /// // Values between `0` and `min` are Subnormal.
756    /// assert!(!lower_than_min.is_normal());
757    /// ```
758    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
759    #[must_use]
760    #[stable(feature = "rust1", since = "1.0.0")]
761    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
762    #[inline]
763    pub const fn is_normal(self) -> bool {
764        #[allow(non_exhaustive_omitted_patterns)] match self.classify() {
    FpCategory::Normal => true,
    _ => false,
}matches!(self.classify(), FpCategory::Normal)
765    }
766
767    /// Returns the floating point category of the number. If only one property
768    /// is going to be tested, it is generally faster to use the specific
769    /// predicate instead.
770    ///
771    /// ```
772    /// use std::num::FpCategory;
773    ///
774    /// let num = 12.4_f32;
775    /// let inf = f32::INFINITY;
776    ///
777    /// assert_eq!(num.classify(), FpCategory::Normal);
778    /// assert_eq!(inf.classify(), FpCategory::Infinite);
779    /// ```
780    #[stable(feature = "rust1", since = "1.0.0")]
781    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
782    #[must_use]
783    pub const fn classify(self) -> FpCategory {
784        // We used to have complicated logic here that avoids the simple bit-based tests to work
785        // around buggy codegen for x87 targets (see
786        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
787        // of our tests is able to find any difference between the complicated and the naive
788        // version, so now we are back to the naive version.
789        let b = self.to_bits();
790        match (b & Self::MANTISSA_MASK, b & Self::EXPONENT_MASK) {
791            (0, Self::EXPONENT_MASK) => FpCategory::Infinite,
792            (_, Self::EXPONENT_MASK) => FpCategory::Nan,
793            (0, 0) => FpCategory::Zero,
794            (_, 0) => FpCategory::Subnormal,
795            _ => FpCategory::Normal,
796        }
797    }
798
799    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
800    /// positive sign bit and positive infinity.
801    ///
802    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
803    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
804    /// conserved over arithmetic operations, the result of `is_sign_positive` on
805    /// a NaN might produce an unexpected or non-portable result. See the [specification
806    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
807    /// if you need fully portable behavior (will return `false` for all NaNs).
808    ///
809    /// ```
810    /// let f = 7.0_f32;
811    /// let g = -7.0_f32;
812    ///
813    /// assert!(f.is_sign_positive());
814    /// assert!(!g.is_sign_positive());
815    /// ```
816    #[must_use]
817    #[stable(feature = "rust1", since = "1.0.0")]
818    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
819    #[inline]
820    pub const fn is_sign_positive(self) -> bool {
821        !self.is_sign_negative()
822    }
823
824    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
825    /// negative sign bit and negative infinity.
826    ///
827    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
828    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
829    /// conserved over arithmetic operations, the result of `is_sign_negative` on
830    /// a NaN might produce an unexpected or non-portable result. See the [specification
831    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
832    /// if you need fully portable behavior (will return `false` for all NaNs).
833    ///
834    /// ```
835    /// let f = 7.0f32;
836    /// let g = -7.0f32;
837    ///
838    /// assert!(!f.is_sign_negative());
839    /// assert!(g.is_sign_negative());
840    /// ```
841    #[must_use]
842    #[stable(feature = "rust1", since = "1.0.0")]
843    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
844    #[inline]
845    pub const fn is_sign_negative(self) -> bool {
846        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
847        // applies to zeros and NaNs as well.
848        self.to_bits() & 0x8000_0000 != 0
849    }
850
851    /// Returns the least number greater than `self`.
852    ///
853    /// Let `TINY` be the smallest representable positive `f32`. Then,
854    ///  - if `self.is_nan()`, this returns `self`;
855    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
856    ///  - if `self` is `-TINY`, this returns -0.0;
857    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
858    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
859    ///  - otherwise the unique least value greater than `self` is returned.
860    ///
861    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
862    /// is finite `x == x.next_up().next_down()` also holds.
863    ///
864    /// ```rust
865    /// // f32::EPSILON is the difference between 1.0 and the next number up.
866    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
867    /// // But not for most numbers.
868    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
869    /// assert_eq!(16777216f32.next_up(), 16777218.0);
870    /// ```
871    ///
872    /// This operation corresponds to IEEE-754 `nextUp`.
873    ///
874    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
875    /// [`INFINITY`]: Self::INFINITY
876    /// [`MIN`]: Self::MIN
877    /// [`MAX`]: Self::MAX
878    #[inline]
879    #[doc(alias = "nextUp")]
880    #[stable(feature = "float_next_up_down", since = "1.86.0")]
881    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
882    #[must_use = "method returns a new number and does not mutate the original value"]
883    pub const fn next_up(self) -> Self {
884        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
885        // denormals to zero. This is in general unsound and unsupported, but here
886        // we do our best to still produce the correct result on such targets.
887        let bits = self.to_bits();
888        if self.is_nan() || bits == Self::INFINITY.to_bits() {
889            return self;
890        }
891
892        let abs = bits & !Self::SIGN_MASK;
893        let next_bits = if abs == 0 {
894            Self::TINY_BITS
895        } else if bits == abs {
896            bits + 1
897        } else {
898            bits - 1
899        };
900        Self::from_bits(next_bits)
901    }
902
903    /// Returns the greatest number less than `self`.
904    ///
905    /// Let `TINY` be the smallest representable positive `f32`. Then,
906    ///  - if `self.is_nan()`, this returns `self`;
907    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
908    ///  - if `self` is `TINY`, this returns 0.0;
909    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
910    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
911    ///  - otherwise the unique greatest value less than `self` is returned.
912    ///
913    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
914    /// is finite `x == x.next_down().next_up()` also holds.
915    ///
916    /// ```rust
917    /// let x = 1.0f32;
918    /// // Clamp value into range [0, 1).
919    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
920    /// assert!(clamped < 1.0);
921    /// assert_eq!(clamped.next_up(), 1.0);
922    /// ```
923    ///
924    /// This operation corresponds to IEEE-754 `nextDown`.
925    ///
926    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
927    /// [`INFINITY`]: Self::INFINITY
928    /// [`MIN`]: Self::MIN
929    /// [`MAX`]: Self::MAX
930    #[inline]
931    #[doc(alias = "nextDown")]
932    #[stable(feature = "float_next_up_down", since = "1.86.0")]
933    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
934    #[must_use = "method returns a new number and does not mutate the original value"]
935    pub const fn next_down(self) -> Self {
936        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
937        // denormals to zero. This is in general unsound and unsupported, but here
938        // we do our best to still produce the correct result on such targets.
939        let bits = self.to_bits();
940        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
941            return self;
942        }
943
944        let abs = bits & !Self::SIGN_MASK;
945        let next_bits = if abs == 0 {
946            Self::NEG_TINY_BITS
947        } else if bits == abs {
948            bits - 1
949        } else {
950            bits + 1
951        };
952        Self::from_bits(next_bits)
953    }
954
955    /// Takes the reciprocal (inverse) of a number, `1/x`.
956    ///
957    /// ```
958    /// let x = 2.0_f32;
959    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
960    ///
961    /// assert!(abs_difference <= f32::EPSILON);
962    /// ```
963    #[must_use = "this returns the result of the operation, without modifying the original"]
964    #[stable(feature = "rust1", since = "1.0.0")]
965    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
966    #[inline]
967    pub const fn recip(self) -> f32 {
968        1.0 / self
969    }
970
971    /// Converts radians to degrees.
972    ///
973    /// # Unspecified precision
974    ///
975    /// The precision of this function is non-deterministic. This means it varies by platform,
976    /// Rust version, and can even differ within the same execution from one invocation to the next.
977    ///
978    /// # Examples
979    ///
980    /// ```
981    /// let angle = std::f32::consts::PI;
982    ///
983    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
984    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
985    /// assert!(abs_difference <= f32::EPSILON);
986    /// ```
987    #[must_use = "this returns the result of the operation, \
988                  without modifying the original"]
989    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
990    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
991    #[inline]
992    pub const fn to_degrees(self) -> f32 {
993        // Use a literal to avoid double rounding, consts::PI is already rounded,
994        // and dividing would round again.
995        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
996        self * PIS_IN_180
997    }
998
999    /// Converts degrees to radians.
1000    ///
1001    /// # Unspecified precision
1002    ///
1003    /// The precision of this function is non-deterministic. This means it varies by platform,
1004    /// Rust version, and can even differ within the same execution from one invocation to the next.
1005    ///
1006    /// # Examples
1007    ///
1008    /// ```
1009    /// let angle = 180.0f32;
1010    ///
1011    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
1012    ///
1013    /// assert!(abs_difference <= f32::EPSILON);
1014    /// ```
1015    #[must_use = "this returns the result of the operation, \
1016                  without modifying the original"]
1017    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
1018    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1019    #[inline]
1020    pub const fn to_radians(self) -> f32 {
1021        // The division here is correctly rounded with respect to the true value of π/180.
1022        // Although π is irrational and already rounded, the double rounding happens
1023        // to produce correct result for f32.
1024        const RADS_PER_DEG: f32 = consts::PI / 180.0;
1025        self * RADS_PER_DEG
1026    }
1027
1028    /// Returns the maximum of the two numbers, ignoring NaN.
1029    ///
1030    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1031    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1032    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1033    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1034    /// non-deterministically.
1035    ///
1036    /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all
1037    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1038    /// follows the IEEE 754-2008 semantics for `maxNum`.
1039    ///
1040    /// ```
1041    /// let x = 1.0f32;
1042    /// let y = 2.0f32;
1043    ///
1044    /// assert_eq!(x.max(y), y);
1045    /// assert_eq!(x.max(f32::NAN), x);
1046    /// ```
1047    #[must_use = "this returns the result of the comparison, without modifying either input"]
1048    #[stable(feature = "rust1", since = "1.0.0")]
1049    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1050    #[inline]
1051    pub const fn max(self, other: f32) -> f32 {
1052        intrinsics::maximum_number_nsz_f32(self, other)
1053    }
1054
1055    /// Returns the minimum of the two numbers, ignoring NaN.
1056    ///
1057    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1058    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1059    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1060    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1061    /// non-deterministically.
1062    ///
1063    /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all
1064    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1065    /// follows the IEEE 754-2008 semantics for `minNum`.
1066    ///
1067    /// ```
1068    /// let x = 1.0f32;
1069    /// let y = 2.0f32;
1070    ///
1071    /// assert_eq!(x.min(y), x);
1072    /// assert_eq!(x.min(f32::NAN), x);
1073    /// ```
1074    #[must_use = "this returns the result of the comparison, without modifying either input"]
1075    #[stable(feature = "rust1", since = "1.0.0")]
1076    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1077    #[inline]
1078    pub const fn min(self, other: f32) -> f32 {
1079        intrinsics::minimum_number_nsz_f32(self, other)
1080    }
1081
1082    /// Returns the maximum of the two numbers, propagating NaN.
1083    ///
1084    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1085    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1086    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1087    /// non-NaN inputs.
1088    ///
1089    /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN,
1090    /// and which does not reliably order `-0.0` and `+0.0`.
1091    ///
1092    /// This follows the IEEE 754-2019 semantics for `maximum`.
1093    ///
1094    /// ```
1095    /// #![feature(float_minimum_maximum)]
1096    /// let x = 1.0f32;
1097    /// let y = 2.0f32;
1098    ///
1099    /// assert_eq!(x.maximum(y), y);
1100    /// assert!(x.maximum(f32::NAN).is_nan());
1101    /// ```
1102    #[must_use = "this returns the result of the comparison, without modifying either input"]
1103    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1104    #[inline]
1105    pub const fn maximum(self, other: f32) -> f32 {
1106        intrinsics::maximumf32(self, other)
1107    }
1108
1109    /// Returns the minimum of the two numbers, propagating NaN.
1110    ///
1111    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1112    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1113    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1114    /// non-NaN inputs.
1115    ///
1116    /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN,
1117    /// and which does not reliably order `-0.0` and `+0.0`.
1118    ///
1119    /// This follows the IEEE 754-2019 semantics for `minimum`.
1120    ///
1121    /// ```
1122    /// #![feature(float_minimum_maximum)]
1123    /// let x = 1.0f32;
1124    /// let y = 2.0f32;
1125    ///
1126    /// assert_eq!(x.minimum(y), x);
1127    /// assert!(x.minimum(f32::NAN).is_nan());
1128    /// ```
1129    #[must_use = "this returns the result of the comparison, without modifying either input"]
1130    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1131    #[inline]
1132    pub const fn minimum(self, other: f32) -> f32 {
1133        intrinsics::minimumf32(self, other)
1134    }
1135
1136    /// Calculates the midpoint (average) between `self` and `rhs`.
1137    ///
1138    /// This returns NaN when *either* argument is NaN or if a combination of
1139    /// +inf and -inf is provided as arguments.
1140    ///
1141    /// # Examples
1142    ///
1143    /// ```
1144    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1145    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1146    /// ```
1147    #[inline]
1148    #[doc(alias = "average")]
1149    #[stable(feature = "num_midpoint", since = "1.85.0")]
1150    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1151    #[must_use = "this returns the result of the operation, \
1152                  without modifying the original"]
1153    pub const fn midpoint(self, other: f32) -> f32 {
1154        cfg_select! {
1155            // Allow faster implementation that have known good 64-bit float
1156            // implementations. Falling back to the branchy code on targets that don't
1157            // have 64-bit hardware floats or buggy implementations.
1158            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1159            any(
1160                target_arch = "x86_64",
1161                target_arch = "aarch64",
1162                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1163                all(target_arch = "loongarch64", target_feature = "d"),
1164                all(target_arch = "arm", target_feature = "vfp2"),
1165                target_arch = "wasm32",
1166                target_arch = "wasm64",
1167            ) => {
1168                ((self as f64 + other as f64) * 0.5) as f32
1169            }
1170            _ => {
1171                const HI: f32 = f32::MAX * 0.5;
1172
1173                let (a, b) = (self, other);
1174                let abs_a = a.abs();
1175                let abs_b = b.abs();
1176
1177                if abs_a <= HI && abs_b <= HI {
1178                    // Overflow is impossible
1179                    (a + b) * 0.5
1180                } else {
1181                    (a * 0.5) + (b * 0.5)
1182                }
1183            }
1184        }
1185    }
1186
1187    /// Rounds toward zero and converts to any primitive integer type,
1188    /// assuming that the value is finite and fits in that type.
1189    ///
1190    /// ```
1191    /// let value = 4.6_f32;
1192    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1193    /// assert_eq!(rounded, 4);
1194    ///
1195    /// let value = -128.9_f32;
1196    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1197    /// assert_eq!(rounded, i8::MIN);
1198    /// ```
1199    ///
1200    /// # Safety
1201    ///
1202    /// The value must:
1203    ///
1204    /// * Not be `NaN`
1205    /// * Not be infinite
1206    /// * Be representable in the return type `Int`, after truncating off its fractional part
1207    #[must_use = "this returns the result of the operation, \
1208                  without modifying the original"]
1209    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1210    #[inline]
1211    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1212    where
1213        Self: FloatToInt<Int>,
1214    {
1215        // SAFETY: the caller must uphold the safety contract for
1216        // `FloatToInt::to_int_unchecked`.
1217        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1218    }
1219
1220    /// Raw transmutation to `u32`.
1221    ///
1222    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1223    ///
1224    /// See [`from_bits`](Self::from_bits) for some discussion of the
1225    /// portability of this operation (there are almost no issues).
1226    ///
1227    /// Note that this function is distinct from `as` casting, which attempts to
1228    /// preserve the *numeric* value, and not the bitwise value.
1229    ///
1230    /// # Examples
1231    ///
1232    /// ```
1233    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1234    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1235    ///
1236    /// ```
1237    #[must_use = "this returns the result of the operation, \
1238                  without modifying the original"]
1239    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1240    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1241    #[inline]
1242    #[allow(unnecessary_transmutes)]
1243    pub const fn to_bits(self) -> u32 {
1244        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1245        unsafe { mem::transmute(self) }
1246    }
1247
1248    /// Raw transmutation from `u32`.
1249    ///
1250    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1251    /// It turns out this is incredibly portable, for two reasons:
1252    ///
1253    /// * Floats and Ints have the same endianness on all supported platforms.
1254    /// * IEEE 754 very precisely specifies the bit layout of floats.
1255    ///
1256    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1257    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1258    /// (notably x86 and ARM) picked the interpretation that was ultimately
1259    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1260    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1261    ///
1262    /// Rather than trying to preserve signaling-ness cross-platform, this
1263    /// implementation favors preserving the exact bits. This means that
1264    /// any payloads encoded in NaNs will be preserved even if the result of
1265    /// this method is sent over the network from an x86 machine to a MIPS one.
1266    ///
1267    /// If the results of this method are only manipulated by the same
1268    /// architecture that produced them, then there is no portability concern.
1269    ///
1270    /// If the input isn't NaN, then there is no portability concern.
1271    ///
1272    /// If you don't care about signalingness (very likely), then there is no
1273    /// portability concern.
1274    ///
1275    /// Note that this function is distinct from `as` casting, which attempts to
1276    /// preserve the *numeric* value, and not the bitwise value.
1277    ///
1278    /// # Examples
1279    ///
1280    /// ```
1281    /// let v = f32::from_bits(0x41480000);
1282    /// assert_eq!(v, 12.5);
1283    /// ```
1284    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1285    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1286    #[must_use]
1287    #[inline]
1288    #[allow(unnecessary_transmutes)]
1289    pub const fn from_bits(v: u32) -> Self {
1290        // It turns out the safety issues with sNaN were overblown! Hooray!
1291        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1292        unsafe { mem::transmute(v) }
1293    }
1294
1295    /// Returns the memory representation of this floating point number as a byte array in
1296    /// big-endian (network) byte order.
1297    ///
1298    /// See [`from_bits`](Self::from_bits) for some discussion of the
1299    /// portability of this operation (there are almost no issues).
1300    ///
1301    /// # Examples
1302    ///
1303    /// ```
1304    /// let bytes = 12.5f32.to_be_bytes();
1305    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1306    /// ```
1307    #[must_use = "this returns the result of the operation, \
1308                  without modifying the original"]
1309    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1310    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1311    #[inline]
1312    pub const fn to_be_bytes(self) -> [u8; 4] {
1313        self.to_bits().to_be_bytes()
1314    }
1315
1316    /// Returns the memory representation of this floating point number as a byte array in
1317    /// little-endian byte order.
1318    ///
1319    /// See [`from_bits`](Self::from_bits) for some discussion of the
1320    /// portability of this operation (there are almost no issues).
1321    ///
1322    /// # Examples
1323    ///
1324    /// ```
1325    /// let bytes = 12.5f32.to_le_bytes();
1326    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1327    /// ```
1328    #[must_use = "this returns the result of the operation, \
1329                  without modifying the original"]
1330    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1331    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1332    #[inline]
1333    pub const fn to_le_bytes(self) -> [u8; 4] {
1334        self.to_bits().to_le_bytes()
1335    }
1336
1337    /// Returns the memory representation of this floating point number as a byte array in
1338    /// native byte order.
1339    ///
1340    /// As the target platform's native endianness is used, portable code
1341    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1342    ///
1343    /// [`to_be_bytes`]: f32::to_be_bytes
1344    /// [`to_le_bytes`]: f32::to_le_bytes
1345    ///
1346    /// See [`from_bits`](Self::from_bits) for some discussion of the
1347    /// portability of this operation (there are almost no issues).
1348    ///
1349    /// # Examples
1350    ///
1351    /// ```
1352    /// let bytes = 12.5f32.to_ne_bytes();
1353    /// assert_eq!(
1354    ///     bytes,
1355    ///     if cfg!(target_endian = "big") {
1356    ///         [0x41, 0x48, 0x00, 0x00]
1357    ///     } else {
1358    ///         [0x00, 0x00, 0x48, 0x41]
1359    ///     }
1360    /// );
1361    /// ```
1362    #[must_use = "this returns the result of the operation, \
1363                  without modifying the original"]
1364    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1365    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1366    #[inline]
1367    pub const fn to_ne_bytes(self) -> [u8; 4] {
1368        self.to_bits().to_ne_bytes()
1369    }
1370
1371    /// Creates a floating point value from its representation as a byte array in big endian.
1372    ///
1373    /// See [`from_bits`](Self::from_bits) for some discussion of the
1374    /// portability of this operation (there are almost no issues).
1375    ///
1376    /// # Examples
1377    ///
1378    /// ```
1379    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1380    /// assert_eq!(value, 12.5);
1381    /// ```
1382    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1383    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1384    #[must_use]
1385    #[inline]
1386    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1387        Self::from_bits(u32::from_be_bytes(bytes))
1388    }
1389
1390    /// Creates a floating point value from its representation as a byte array in little endian.
1391    ///
1392    /// See [`from_bits`](Self::from_bits) for some discussion of the
1393    /// portability of this operation (there are almost no issues).
1394    ///
1395    /// # Examples
1396    ///
1397    /// ```
1398    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1399    /// assert_eq!(value, 12.5);
1400    /// ```
1401    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1402    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1403    #[must_use]
1404    #[inline]
1405    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1406        Self::from_bits(u32::from_le_bytes(bytes))
1407    }
1408
1409    /// Creates a floating point value from its representation as a byte array in native endian.
1410    ///
1411    /// As the target platform's native endianness is used, portable code
1412    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1413    /// appropriate instead.
1414    ///
1415    /// [`from_be_bytes`]: f32::from_be_bytes
1416    /// [`from_le_bytes`]: f32::from_le_bytes
1417    ///
1418    /// See [`from_bits`](Self::from_bits) for some discussion of the
1419    /// portability of this operation (there are almost no issues).
1420    ///
1421    /// # Examples
1422    ///
1423    /// ```
1424    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1425    ///     [0x41, 0x48, 0x00, 0x00]
1426    /// } else {
1427    ///     [0x00, 0x00, 0x48, 0x41]
1428    /// });
1429    /// assert_eq!(value, 12.5);
1430    /// ```
1431    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1432    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1433    #[must_use]
1434    #[inline]
1435    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1436        Self::from_bits(u32::from_ne_bytes(bytes))
1437    }
1438
1439    /// Returns the ordering between `self` and `other`.
1440    ///
1441    /// Unlike the standard partial comparison between floating point numbers,
1442    /// this comparison always produces an ordering in accordance to
1443    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1444    /// floating point standard. The values are ordered in the following sequence:
1445    ///
1446    /// - negative quiet NaN
1447    /// - negative signaling NaN
1448    /// - negative infinity
1449    /// - negative numbers
1450    /// - negative subnormal numbers
1451    /// - negative zero
1452    /// - positive zero
1453    /// - positive subnormal numbers
1454    /// - positive numbers
1455    /// - positive infinity
1456    /// - positive signaling NaN
1457    /// - positive quiet NaN.
1458    ///
1459    /// The ordering established by this function does not always agree with the
1460    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1461    /// they consider negative and positive zero equal, while `total_cmp`
1462    /// doesn't.
1463    ///
1464    /// The interpretation of the signaling NaN bit follows the definition in
1465    /// the IEEE 754 standard, which may not match the interpretation by some of
1466    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1467    ///
1468    /// # Example
1469    ///
1470    /// ```
1471    /// struct GoodBoy {
1472    ///     name: String,
1473    ///     weight: f32,
1474    /// }
1475    ///
1476    /// let mut bois = vec![
1477    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1478    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1479    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1480    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1481    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1482    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1483    /// ];
1484    ///
1485    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1486    ///
1487    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1488    /// if f32::NAN.is_sign_negative() {
1489    ///     assert!(bois.into_iter().map(|b| b.weight)
1490    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1491    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1492    /// } else {
1493    ///     assert!(bois.into_iter().map(|b| b.weight)
1494    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1495    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1496    /// }
1497    /// ```
1498    #[stable(feature = "total_cmp", since = "1.62.0")]
1499    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1500    #[must_use]
1501    #[inline]
1502    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1503        let mut left = self.to_bits() as i32;
1504        let mut right = other.to_bits() as i32;
1505
1506        // In case of negatives, flip all the bits except the sign
1507        // to achieve a similar layout as two's complement integers
1508        //
1509        // Why does this work? IEEE 754 floats consist of three fields:
1510        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1511        // fields as a whole have the property that their bitwise order is
1512        // equal to the numeric magnitude where the magnitude is defined.
1513        // The magnitude is not normally defined on NaN values, but
1514        // IEEE 754 totalOrder defines the NaN values also to follow the
1515        // bitwise order. This leads to order explained in the doc comment.
1516        // However, the representation of magnitude is the same for negative
1517        // and positive numbers – only the sign bit is different.
1518        // To easily compare the floats as signed integers, we need to
1519        // flip the exponent and mantissa bits in case of negative numbers.
1520        // We effectively convert the numbers to "two's complement" form.
1521        //
1522        // To do the flipping, we construct a mask and XOR against it.
1523        // We branchlessly calculate an "all-ones except for the sign bit"
1524        // mask from negative-signed values: right shifting sign-extends
1525        // the integer, so we "fill" the mask with sign bits, and then
1526        // convert to unsigned to push one more zero bit.
1527        // On positive values, the mask is all zeros, so it's a no-op.
1528        left ^= (((left >> 31) as u32) >> 1) as i32;
1529        right ^= (((right >> 31) as u32) >> 1) as i32;
1530
1531        left.cmp(&right)
1532    }
1533
1534    /// Restrict a value to a certain interval unless it is NaN.
1535    ///
1536    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1537    /// less than `min`. Otherwise this returns `self`.
1538    ///
1539    /// Note that this function returns NaN if the initial value was NaN as
1540    /// well. If the result is zero and among the three inputs `self`, `min`, and `max` there are
1541    /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically.
1542    ///
1543    /// # Panics
1544    ///
1545    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1546    ///
1547    /// # Examples
1548    ///
1549    /// ```
1550    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1551    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1552    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1553    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1554    ///
1555    /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic.
1556    /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0);
1557    /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0);
1558    /// // This is definitely a negative zero.
1559    /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative());
1560    /// ```
1561    #[must_use = "method returns a new number and does not mutate the original value"]
1562    #[stable(feature = "clamp", since = "1.50.0")]
1563    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1564    #[inline]
1565    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1566        {
    if !(min <= max) {
        {
            #[rustc_allow_const_fn_unstable(const_eval_select)]
            #[inline(always)]
            #[track_caller]
            const fn do_panic(min: f32, max: f32) -> ! {
                {
                    #[inline]
                    #[track_caller]
                    fn runtime(min: f32, max: f32) -> ! {
                        {
                            {
                                crate::panicking::panic_fmt(format_args!("min > max, or either was NaN. min = {0:?}, max = {1:?}",
                                        min, max));
                            }
                        }
                    }
                    #[inline]
                    #[track_caller]
                    const fn compiletime(min: f32, max: f32) -> ! {
                        let _ = min;
                        let _ = max;
                        {
                            {
                                crate::panicking::panic_fmt(format_args!("min > max, or either was NaN"));
                            }
                        }
                    }
                    const_eval_select((min, max), compiletime, runtime)
                }
            }
            do_panic(min, max)
        }
    }
};const_assert!(
1567            min <= max,
1568            "min > max, or either was NaN",
1569            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1570            min: f32,
1571            max: f32,
1572        );
1573
1574        if self < min {
1575            self = min;
1576        }
1577        if self > max {
1578            self = max;
1579        }
1580        self
1581    }
1582
1583    /// Clamps this number to a symmetric range centered around zero.
1584    ///
1585    /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
1586    ///
1587    /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
1588    /// explicit about the intent.
1589    ///
1590    /// # Panics
1591    ///
1592    /// Panics if `limit` is negative or NaN, as this indicates a logic error.
1593    ///
1594    /// # Examples
1595    ///
1596    /// ```
1597    /// #![feature(clamp_magnitude)]
1598    /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0);
1599    /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0);
1600    /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0);
1601    /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0);
1602    /// ```
1603    #[must_use = "this returns the clamped value and does not modify the original"]
1604    #[unstable(feature = "clamp_magnitude", issue = "148519")]
1605    #[inline]
1606    pub fn clamp_magnitude(self, limit: f32) -> f32 {
1607        if !(limit >= 0.0) {
    {
        crate::panicking::panic_fmt(format_args!("limit must be non-negative"));
    }
};assert!(limit >= 0.0, "limit must be non-negative");
1608        let limit = limit.abs(); // Canonicalises -0.0 to 0.0
1609        self.clamp(-limit, limit)
1610    }
1611
1612    /// Computes the absolute value of `self`.
1613    ///
1614    /// This function always returns the precise result.
1615    ///
1616    /// # Examples
1617    ///
1618    /// ```
1619    /// let x = 3.5_f32;
1620    /// let y = -3.5_f32;
1621    ///
1622    /// assert_eq!(x.abs(), x);
1623    /// assert_eq!(y.abs(), -y);
1624    ///
1625    /// assert!(f32::NAN.abs().is_nan());
1626    /// ```
1627    #[must_use = "method returns a new number and does not mutate the original value"]
1628    #[stable(feature = "rust1", since = "1.0.0")]
1629    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1630    #[inline]
1631    pub const fn abs(self) -> f32 {
1632        intrinsics::fabs(self)
1633    }
1634
1635    /// Returns a number that represents the sign of `self`.
1636    ///
1637    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1638    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1639    /// - NaN if the number is NaN
1640    ///
1641    /// # Examples
1642    ///
1643    /// ```
1644    /// let f = 3.5_f32;
1645    ///
1646    /// assert_eq!(f.signum(), 1.0);
1647    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1648    ///
1649    /// assert!(f32::NAN.signum().is_nan());
1650    /// ```
1651    #[must_use = "method returns a new number and does not mutate the original value"]
1652    #[stable(feature = "rust1", since = "1.0.0")]
1653    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1654    #[inline]
1655    pub const fn signum(self) -> f32 {
1656        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1657    }
1658
1659    /// Returns a number composed of the magnitude of `self` and the sign of
1660    /// `sign`.
1661    ///
1662    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1663    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1664    /// returned.
1665    ///
1666    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1667    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1668    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1669    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1670    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1671    /// info.
1672    ///
1673    /// # Examples
1674    ///
1675    /// ```
1676    /// let f = 3.5_f32;
1677    ///
1678    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1679    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1680    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1681    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1682    ///
1683    /// assert!(f32::NAN.copysign(1.0).is_nan());
1684    /// ```
1685    #[must_use = "method returns a new number and does not mutate the original value"]
1686    #[inline]
1687    #[stable(feature = "copysign", since = "1.35.0")]
1688    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1689    pub const fn copysign(self, sign: f32) -> f32 {
1690        intrinsics::copysignf32(self, sign)
1691    }
1692
1693    /// Float addition that allows optimizations based on algebraic rules.
1694    ///
1695    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1696    #[must_use = "method returns a new number and does not mutate the original value"]
1697    #[unstable(feature = "float_algebraic", issue = "136469")]
1698    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1699    #[inline]
1700    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1701        intrinsics::fadd_algebraic(self, rhs)
1702    }
1703
1704    /// Float subtraction that allows optimizations based on algebraic rules.
1705    ///
1706    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1707    #[must_use = "method returns a new number and does not mutate the original value"]
1708    #[unstable(feature = "float_algebraic", issue = "136469")]
1709    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1710    #[inline]
1711    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1712        intrinsics::fsub_algebraic(self, rhs)
1713    }
1714
1715    /// Float multiplication that allows optimizations based on algebraic rules.
1716    ///
1717    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1718    #[must_use = "method returns a new number and does not mutate the original value"]
1719    #[unstable(feature = "float_algebraic", issue = "136469")]
1720    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1721    #[inline]
1722    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1723        intrinsics::fmul_algebraic(self, rhs)
1724    }
1725
1726    /// Float division that allows optimizations based on algebraic rules.
1727    ///
1728    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1729    #[must_use = "method returns a new number and does not mutate the original value"]
1730    #[unstable(feature = "float_algebraic", issue = "136469")]
1731    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1732    #[inline]
1733    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1734        intrinsics::fdiv_algebraic(self, rhs)
1735    }
1736
1737    /// Float remainder that allows optimizations based on algebraic rules.
1738    ///
1739    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1740    #[must_use = "method returns a new number and does not mutate the original value"]
1741    #[unstable(feature = "float_algebraic", issue = "136469")]
1742    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1743    #[inline]
1744    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1745        intrinsics::frem_algebraic(self, rhs)
1746    }
1747}
1748
1749/// Experimental implementations of floating point functions in `core`.
1750///
1751/// _The standalone functions in this module are for testing only.
1752/// They will be stabilized as inherent methods._
1753#[unstable(feature = "core_float_math", issue = "137578")]
1754pub mod math {
1755    use crate::intrinsics;
1756    use crate::num::imp::libm;
1757
1758    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1759    ///
1760    /// # Examples
1761    ///
1762    /// ```
1763    /// #![feature(core_float_math)]
1764    ///
1765    /// use core::f32;
1766    ///
1767    /// let f = 3.7_f32;
1768    /// let g = 3.0_f32;
1769    /// let h = -3.7_f32;
1770    ///
1771    /// assert_eq!(f32::math::floor(f), 3.0);
1772    /// assert_eq!(f32::math::floor(g), 3.0);
1773    /// assert_eq!(f32::math::floor(h), -4.0);
1774    /// ```
1775    ///
1776    /// _This standalone function is for testing only.
1777    /// It will be stabilized as an inherent method._
1778    ///
1779    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
1780    #[inline]
1781    #[unstable(feature = "core_float_math", issue = "137578")]
1782    #[must_use = "method returns a new number and does not mutate the original value"]
1783    pub const fn floor(x: f32) -> f32 {
1784        intrinsics::floorf32(x)
1785    }
1786
1787    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1788    ///
1789    /// # Examples
1790    ///
1791    /// ```
1792    /// #![feature(core_float_math)]
1793    ///
1794    /// use core::f32;
1795    ///
1796    /// let f = 3.01_f32;
1797    /// let g = 4.0_f32;
1798    ///
1799    /// assert_eq!(f32::math::ceil(f), 4.0);
1800    /// assert_eq!(f32::math::ceil(g), 4.0);
1801    /// ```
1802    ///
1803    /// _This standalone function is for testing only.
1804    /// It will be stabilized as an inherent method._
1805    ///
1806    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1807    #[inline]
1808    #[doc(alias = "ceiling")]
1809    #[must_use = "method returns a new number and does not mutate the original value"]
1810    #[unstable(feature = "core_float_math", issue = "137578")]
1811    pub const fn ceil(x: f32) -> f32 {
1812        intrinsics::ceilf32(x)
1813    }
1814
1815    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1816    ///
1817    /// # Examples
1818    ///
1819    /// ```
1820    /// #![feature(core_float_math)]
1821    ///
1822    /// use core::f32;
1823    ///
1824    /// let f = 3.3_f32;
1825    /// let g = -3.3_f32;
1826    /// let h = -3.7_f32;
1827    /// let i = 3.5_f32;
1828    /// let j = 4.5_f32;
1829    ///
1830    /// assert_eq!(f32::math::round(f), 3.0);
1831    /// assert_eq!(f32::math::round(g), -3.0);
1832    /// assert_eq!(f32::math::round(h), -4.0);
1833    /// assert_eq!(f32::math::round(i), 4.0);
1834    /// assert_eq!(f32::math::round(j), 5.0);
1835    /// ```
1836    ///
1837    /// _This standalone function is for testing only.
1838    /// It will be stabilized as an inherent method._
1839    ///
1840    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1841    #[inline]
1842    #[unstable(feature = "core_float_math", issue = "137578")]
1843    #[must_use = "method returns a new number and does not mutate the original value"]
1844    pub const fn round(x: f32) -> f32 {
1845        intrinsics::roundf32(x)
1846    }
1847
1848    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1849    /// details.
1850    ///
1851    /// # Examples
1852    ///
1853    /// ```
1854    /// #![feature(core_float_math)]
1855    ///
1856    /// use core::f32;
1857    ///
1858    /// let f = 3.3_f32;
1859    /// let g = -3.3_f32;
1860    /// let h = 3.5_f32;
1861    /// let i = 4.5_f32;
1862    ///
1863    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1864    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1865    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1866    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1867    /// ```
1868    ///
1869    /// _This standalone function is for testing only.
1870    /// It will be stabilized as an inherent method._
1871    ///
1872    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1873    #[inline]
1874    #[unstable(feature = "core_float_math", issue = "137578")]
1875    #[must_use = "method returns a new number and does not mutate the original value"]
1876    pub const fn round_ties_even(x: f32) -> f32 {
1877        intrinsics::round_ties_even_f32(x)
1878    }
1879
1880    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1881    ///
1882    /// # Examples
1883    ///
1884    /// ```
1885    /// #![feature(core_float_math)]
1886    ///
1887    /// use core::f32;
1888    ///
1889    /// let f = 3.7_f32;
1890    /// let g = 3.0_f32;
1891    /// let h = -3.7_f32;
1892    ///
1893    /// assert_eq!(f32::math::trunc(f), 3.0);
1894    /// assert_eq!(f32::math::trunc(g), 3.0);
1895    /// assert_eq!(f32::math::trunc(h), -3.0);
1896    /// ```
1897    ///
1898    /// _This standalone function is for testing only.
1899    /// It will be stabilized as an inherent method._
1900    ///
1901    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1902    #[inline]
1903    #[doc(alias = "truncate")]
1904    #[must_use = "method returns a new number and does not mutate the original value"]
1905    #[unstable(feature = "core_float_math", issue = "137578")]
1906    pub const fn trunc(x: f32) -> f32 {
1907        intrinsics::truncf32(x)
1908    }
1909
1910    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1911    ///
1912    /// # Examples
1913    ///
1914    /// ```
1915    /// #![feature(core_float_math)]
1916    ///
1917    /// use core::f32;
1918    ///
1919    /// let x = 3.6_f32;
1920    /// let y = -3.6_f32;
1921    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1922    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1923    ///
1924    /// assert!(abs_difference_x <= f32::EPSILON);
1925    /// assert!(abs_difference_y <= f32::EPSILON);
1926    /// ```
1927    ///
1928    /// _This standalone function is for testing only.
1929    /// It will be stabilized as an inherent method._
1930    ///
1931    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1932    #[inline]
1933    #[unstable(feature = "core_float_math", issue = "137578")]
1934    #[must_use = "method returns a new number and does not mutate the original value"]
1935    pub const fn fract(x: f32) -> f32 {
1936        x - trunc(x)
1937    }
1938
1939    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1940    ///
1941    /// # Examples
1942    ///
1943    /// ```
1944    /// # #![allow(unused_features)]
1945    /// #![feature(core_float_math)]
1946    ///
1947    /// # // FIXME(#140515): mingw has an incorrect fma
1948    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1949    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1950    /// use core::f32;
1951    ///
1952    /// let m = 10.0_f32;
1953    /// let x = 4.0_f32;
1954    /// let b = 60.0_f32;
1955    ///
1956    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1957    /// assert_eq!(m * x + b, 100.0);
1958    ///
1959    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1960    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1961    /// let minus_one = -1.0_f32;
1962    ///
1963    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1964    /// assert_eq!(
1965    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1966    ///     -f32::EPSILON * f32::EPSILON
1967    /// );
1968    /// // Different rounding with the non-fused multiply and add.
1969    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1970    /// # }
1971    /// ```
1972    ///
1973    /// _This standalone function is for testing only.
1974    /// It will be stabilized as an inherent method._
1975    ///
1976    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1977    #[inline]
1978    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1979    #[must_use = "method returns a new number and does not mutate the original value"]
1980    #[unstable(feature = "core_float_math", issue = "137578")]
1981    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1982        intrinsics::fmaf32(x, y, z)
1983    }
1984
1985    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1986    ///
1987    /// # Examples
1988    ///
1989    /// ```
1990    /// #![feature(core_float_math)]
1991    ///
1992    /// use core::f32;
1993    ///
1994    /// let a: f32 = 7.0;
1995    /// let b = 4.0;
1996    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
1997    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
1998    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
1999    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
2000    /// ```
2001    ///
2002    /// _This standalone function is for testing only.
2003    /// It will be stabilized as an inherent method._
2004    ///
2005    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
2006    #[inline]
2007    #[unstable(feature = "core_float_math", issue = "137578")]
2008    #[must_use = "method returns a new number and does not mutate the original value"]
2009    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
2010        let q = trunc(x / rhs);
2011        if x % rhs < 0.0 {
2012            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
2013        }
2014        q
2015    }
2016
2017    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
2018    ///
2019    /// # Examples
2020    ///
2021    /// ```
2022    /// #![feature(core_float_math)]
2023    ///
2024    /// use core::f32;
2025    ///
2026    /// let a: f32 = 7.0;
2027    /// let b = 4.0;
2028    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
2029    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
2030    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
2031    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
2032    /// // limitation due to round-off error
2033    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
2034    /// ```
2035    ///
2036    /// _This standalone function is for testing only.
2037    /// It will be stabilized as an inherent method._
2038    ///
2039    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
2040    #[inline]
2041    #[doc(alias = "modulo", alias = "mod")]
2042    #[unstable(feature = "core_float_math", issue = "137578")]
2043    #[must_use = "method returns a new number and does not mutate the original value"]
2044    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
2045        let r = x % rhs;
2046        if r < 0.0 { r + rhs.abs() } else { r }
2047    }
2048
2049    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
2050    ///
2051    /// # Examples
2052    ///
2053    /// ```
2054    /// #![feature(core_float_math)]
2055    ///
2056    /// use core::f32;
2057    ///
2058    /// let x = 2.0_f32;
2059    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
2060    /// assert!(abs_difference <= 1e-5);
2061    ///
2062    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
2063    /// ```
2064    ///
2065    /// _This standalone function is for testing only.
2066    /// It will be stabilized as an inherent method._
2067    ///
2068    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
2069    #[inline]
2070    #[must_use = "method returns a new number and does not mutate the original value"]
2071    #[unstable(feature = "core_float_math", issue = "137578")]
2072    pub fn powi(x: f32, n: i32) -> f32 {
2073        intrinsics::powif32(x, n)
2074    }
2075
2076    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
2077    ///
2078    /// # Examples
2079    ///
2080    /// ```
2081    /// #![feature(core_float_math)]
2082    ///
2083    /// use core::f32;
2084    ///
2085    /// let positive = 4.0_f32;
2086    /// let negative = -4.0_f32;
2087    /// let negative_zero = -0.0_f32;
2088    ///
2089    /// assert_eq!(f32::math::sqrt(positive), 2.0);
2090    /// assert!(f32::math::sqrt(negative).is_nan());
2091    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
2092    /// ```
2093    ///
2094    /// _This standalone function is for testing only.
2095    /// It will be stabilized as an inherent method._
2096    ///
2097    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
2098    #[inline]
2099    #[doc(alias = "squareRoot")]
2100    #[unstable(feature = "core_float_math", issue = "137578")]
2101    #[must_use = "method returns a new number and does not mutate the original value"]
2102    pub fn sqrt(x: f32) -> f32 {
2103        intrinsics::sqrtf32(x)
2104    }
2105
2106    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
2107    ///
2108    /// # Examples
2109    ///
2110    /// ```
2111    /// #![feature(core_float_math)]
2112    ///
2113    /// use core::f32;
2114    ///
2115    /// let x = 3.0f32;
2116    /// let y = -3.0f32;
2117    ///
2118    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
2119    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
2120    ///
2121    /// assert!(abs_difference_x <= 1e-6);
2122    /// assert!(abs_difference_y <= 1e-6);
2123    /// ```
2124    ///
2125    /// _This standalone function is for testing only.
2126    /// It will be stabilized as an inherent method._
2127    ///
2128    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
2129    #[inline]
2130    #[stable(feature = "rust1", since = "1.0.0")]
2131    #[deprecated(
2132        since = "1.10.0",
2133        note = "you probably meant `(self - other).abs()`: \
2134            this operation is `(self - other).max(0.0)` \
2135            except that `abs_sub` also propagates NaNs (also \
2136            known as `fdimf` in C). If you truly need the positive \
2137            difference, consider using that expression or the C function \
2138            `fdimf`, depending on how you wish to handle NaN (please consider \
2139            filing an issue describing your use-case too)."
2140    )]
2141    #[must_use = "method returns a new number and does not mutate the original value"]
2142    pub fn abs_sub(x: f32, other: f32) -> f32 {
2143        libm::fdimf(x, other)
2144    }
2145
2146    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
2147    ///
2148    /// # Unspecified precision
2149    ///
2150    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
2151    /// can even differ within the same execution from one invocation to the next.
2152    /// This function currently corresponds to the `cbrtf` from libc on Unix
2153    /// and Windows. Note that this might change in the future.
2154    ///
2155    /// # Examples
2156    ///
2157    /// ```
2158    /// #![feature(core_float_math)]
2159    ///
2160    /// use core::f32;
2161    ///
2162    /// let x = 8.0f32;
2163    ///
2164    /// // x^(1/3) - 2 == 0
2165    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
2166    ///
2167    /// assert!(abs_difference <= 1e-6);
2168    /// ```
2169    ///
2170    /// _This standalone function is for testing only.
2171    /// It will be stabilized as an inherent method._
2172    ///
2173    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
2174    #[inline]
2175    #[must_use = "method returns a new number and does not mutate the original value"]
2176    #[unstable(feature = "core_float_math", issue = "137578")]
2177    pub fn cbrt(x: f32) -> f32 {
2178        libm::cbrtf(x)
2179    }
2180}