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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
14#[cfg(not(feature = "ferrocene_subset"))]
15use crate::convert::FloatToInt;
16use crate::num::FpCategory;
17#[cfg(not(feature = "ferrocene_subset"))]
18use crate::panic::const_assert;
19#[cfg(not(feature = "ferrocene_subset"))]
20use crate::{cfg_select, intrinsics, mem};
21
22// Ferrocene addition: imports for certified subset
23#[cfg(feature = "ferrocene_subset")]
24#[rustfmt::skip]
25use crate::{intrinsics, mem};
26
27/// The radix or base of the internal representation of `f32`.
28/// Use [`f32::RADIX`] instead.
29///
30/// # Examples
31///
32/// ```rust
33/// // deprecated way
34/// # #[allow(deprecated, deprecated_in_future)]
35/// let r = std::f32::RADIX;
36///
37/// // intended way
38/// let r = f32::RADIX;
39/// ```
40#[stable(feature = "rust1", since = "1.0.0")]
41#[deprecated(since = "TBD", note = "replaced by the `RADIX` associated constant on `f32`")]
42#[rustc_diagnostic_item = "f32_legacy_const_radix"]
43pub const RADIX: u32 = f32::RADIX;
44
45/// Number of significant digits in base 2.
46/// Use [`f32::MANTISSA_DIGITS`] instead.
47///
48/// # Examples
49///
50/// ```rust
51/// // deprecated way
52/// # #[allow(deprecated, deprecated_in_future)]
53/// let d = std::f32::MANTISSA_DIGITS;
54///
55/// // intended way
56/// let d = f32::MANTISSA_DIGITS;
57/// ```
58#[stable(feature = "rust1", since = "1.0.0")]
59#[deprecated(
60    since = "TBD",
61    note = "replaced by the `MANTISSA_DIGITS` associated constant on `f32`"
62)]
63#[rustc_diagnostic_item = "f32_legacy_const_mantissa_dig"]
64pub const MANTISSA_DIGITS: u32 = f32::MANTISSA_DIGITS;
65
66/// Approximate number of significant digits in base 10.
67/// Use [`f32::DIGITS`] instead.
68///
69/// # Examples
70///
71/// ```rust
72/// // deprecated way
73/// # #[allow(deprecated, deprecated_in_future)]
74/// let d = std::f32::DIGITS;
75///
76/// // intended way
77/// let d = f32::DIGITS;
78/// ```
79#[stable(feature = "rust1", since = "1.0.0")]
80#[deprecated(since = "TBD", note = "replaced by the `DIGITS` associated constant on `f32`")]
81#[rustc_diagnostic_item = "f32_legacy_const_digits"]
82pub const DIGITS: u32 = f32::DIGITS;
83
84/// [Machine epsilon] value for `f32`.
85/// Use [`f32::EPSILON`] instead.
86///
87/// This is the difference between `1.0` and the next larger representable number.
88///
89/// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
90///
91/// # Examples
92///
93/// ```rust
94/// // deprecated way
95/// # #[allow(deprecated, deprecated_in_future)]
96/// let e = std::f32::EPSILON;
97///
98/// // intended way
99/// let e = f32::EPSILON;
100/// ```
101#[stable(feature = "rust1", since = "1.0.0")]
102#[deprecated(since = "TBD", note = "replaced by the `EPSILON` associated constant on `f32`")]
103#[rustc_diagnostic_item = "f32_legacy_const_epsilon"]
104pub const EPSILON: f32 = f32::EPSILON;
105
106/// Smallest finite `f32` value.
107/// Use [`f32::MIN`] instead.
108///
109/// # Examples
110///
111/// ```rust
112/// // deprecated way
113/// # #[allow(deprecated, deprecated_in_future)]
114/// let min = std::f32::MIN;
115///
116/// // intended way
117/// let min = f32::MIN;
118/// ```
119#[stable(feature = "rust1", since = "1.0.0")]
120#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on `f32`")]
121#[rustc_diagnostic_item = "f32_legacy_const_min"]
122pub const MIN: f32 = f32::MIN;
123
124/// Smallest positive normal `f32` value.
125/// Use [`f32::MIN_POSITIVE`] instead.
126///
127/// # Examples
128///
129/// ```rust
130/// // deprecated way
131/// # #[allow(deprecated, deprecated_in_future)]
132/// let min = std::f32::MIN_POSITIVE;
133///
134/// // intended way
135/// let min = f32::MIN_POSITIVE;
136/// ```
137#[stable(feature = "rust1", since = "1.0.0")]
138#[deprecated(since = "TBD", note = "replaced by the `MIN_POSITIVE` associated constant on `f32`")]
139#[rustc_diagnostic_item = "f32_legacy_const_min_positive"]
140pub const MIN_POSITIVE: f32 = f32::MIN_POSITIVE;
141
142/// Largest finite `f32` value.
143/// Use [`f32::MAX`] instead.
144///
145/// # Examples
146///
147/// ```rust
148/// // deprecated way
149/// # #[allow(deprecated, deprecated_in_future)]
150/// let max = std::f32::MAX;
151///
152/// // intended way
153/// let max = f32::MAX;
154/// ```
155#[stable(feature = "rust1", since = "1.0.0")]
156#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on `f32`")]
157#[rustc_diagnostic_item = "f32_legacy_const_max"]
158pub const MAX: f32 = f32::MAX;
159
160/// One greater than the minimum possible normal power of 2 exponent.
161/// Use [`f32::MIN_EXP`] instead.
162///
163/// # Examples
164///
165/// ```rust
166/// // deprecated way
167/// # #[allow(deprecated, deprecated_in_future)]
168/// let min = std::f32::MIN_EXP;
169///
170/// // intended way
171/// let min = f32::MIN_EXP;
172/// ```
173#[stable(feature = "rust1", since = "1.0.0")]
174#[deprecated(since = "TBD", note = "replaced by the `MIN_EXP` associated constant on `f32`")]
175#[rustc_diagnostic_item = "f32_legacy_const_min_exp"]
176pub const MIN_EXP: i32 = f32::MIN_EXP;
177
178/// Maximum possible power of 2 exponent.
179/// Use [`f32::MAX_EXP`] instead.
180///
181/// # Examples
182///
183/// ```rust
184/// // deprecated way
185/// # #[allow(deprecated, deprecated_in_future)]
186/// let max = std::f32::MAX_EXP;
187///
188/// // intended way
189/// let max = f32::MAX_EXP;
190/// ```
191#[stable(feature = "rust1", since = "1.0.0")]
192#[deprecated(since = "TBD", note = "replaced by the `MAX_EXP` associated constant on `f32`")]
193#[rustc_diagnostic_item = "f32_legacy_const_max_exp"]
194pub const MAX_EXP: i32 = f32::MAX_EXP;
195
196/// Minimum possible normal power of 10 exponent.
197/// Use [`f32::MIN_10_EXP`] instead.
198///
199/// # Examples
200///
201/// ```rust
202/// // deprecated way
203/// # #[allow(deprecated, deprecated_in_future)]
204/// let min = std::f32::MIN_10_EXP;
205///
206/// // intended way
207/// let min = f32::MIN_10_EXP;
208/// ```
209#[stable(feature = "rust1", since = "1.0.0")]
210#[deprecated(since = "TBD", note = "replaced by the `MIN_10_EXP` associated constant on `f32`")]
211#[rustc_diagnostic_item = "f32_legacy_const_min_10_exp"]
212pub const MIN_10_EXP: i32 = f32::MIN_10_EXP;
213
214/// Maximum possible power of 10 exponent.
215/// Use [`f32::MAX_10_EXP`] instead.
216///
217/// # Examples
218///
219/// ```rust
220/// // deprecated way
221/// # #[allow(deprecated, deprecated_in_future)]
222/// let max = std::f32::MAX_10_EXP;
223///
224/// // intended way
225/// let max = f32::MAX_10_EXP;
226/// ```
227#[stable(feature = "rust1", since = "1.0.0")]
228#[deprecated(since = "TBD", note = "replaced by the `MAX_10_EXP` associated constant on `f32`")]
229#[rustc_diagnostic_item = "f32_legacy_const_max_10_exp"]
230pub const MAX_10_EXP: i32 = f32::MAX_10_EXP;
231
232/// Not a Number (NaN).
233/// Use [`f32::NAN`] instead.
234///
235/// # Examples
236///
237/// ```rust
238/// // deprecated way
239/// # #[allow(deprecated, deprecated_in_future)]
240/// let nan = std::f32::NAN;
241///
242/// // intended way
243/// let nan = f32::NAN;
244/// ```
245#[stable(feature = "rust1", since = "1.0.0")]
246#[deprecated(since = "TBD", note = "replaced by the `NAN` associated constant on `f32`")]
247#[rustc_diagnostic_item = "f32_legacy_const_nan"]
248pub const NAN: f32 = f32::NAN;
249
250/// Infinity (∞).
251/// Use [`f32::INFINITY`] instead.
252///
253/// # Examples
254///
255/// ```rust
256/// // deprecated way
257/// # #[allow(deprecated, deprecated_in_future)]
258/// let inf = std::f32::INFINITY;
259///
260/// // intended way
261/// let inf = f32::INFINITY;
262/// ```
263#[stable(feature = "rust1", since = "1.0.0")]
264#[deprecated(since = "TBD", note = "replaced by the `INFINITY` associated constant on `f32`")]
265#[rustc_diagnostic_item = "f32_legacy_const_infinity"]
266pub const INFINITY: f32 = f32::INFINITY;
267
268/// Negative infinity (−∞).
269/// Use [`f32::NEG_INFINITY`] instead.
270///
271/// # Examples
272///
273/// ```rust
274/// // deprecated way
275/// # #[allow(deprecated, deprecated_in_future)]
276/// let ninf = std::f32::NEG_INFINITY;
277///
278/// // intended way
279/// let ninf = f32::NEG_INFINITY;
280/// ```
281#[stable(feature = "rust1", since = "1.0.0")]
282#[deprecated(since = "TBD", note = "replaced by the `NEG_INFINITY` associated constant on `f32`")]
283#[rustc_diagnostic_item = "f32_legacy_const_neg_infinity"]
284pub const NEG_INFINITY: f32 = f32::NEG_INFINITY;
285
286/// Basic mathematical constants.
287#[stable(feature = "rust1", since = "1.0.0")]
288#[rustc_diagnostic_item = "f32_consts_mod"]
289pub mod consts {
290    // FIXME: replace with mathematical constants from cmath.
291
292    /// Archimedes' constant (π)
293    #[stable(feature = "rust1", since = "1.0.0")]
294    pub const PI: f32 = 3.14159265358979323846264338327950288_f32;
295
296    /// The full circle constant (τ)
297    ///
298    /// Equal to 2π.
299    #[stable(feature = "tau_constant", since = "1.47.0")]
300    pub const TAU: f32 = 6.28318530717958647692528676655900577_f32;
301
302    /// The golden ratio (φ)
303    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
304    pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32;
305
306    /// The Euler-Mascheroni constant (γ)
307    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
308    pub const EULER_GAMMA: f32 = 0.577215664901532860606512090082402431_f32;
309
310    /// π/2
311    #[stable(feature = "rust1", since = "1.0.0")]
312    pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32;
313
314    /// π/3
315    #[stable(feature = "rust1", since = "1.0.0")]
316    pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32;
317
318    /// π/4
319    #[stable(feature = "rust1", since = "1.0.0")]
320    pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32;
321
322    /// π/6
323    #[stable(feature = "rust1", since = "1.0.0")]
324    pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32;
325
326    /// π/8
327    #[stable(feature = "rust1", since = "1.0.0")]
328    pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32;
329
330    /// 1/π
331    #[stable(feature = "rust1", since = "1.0.0")]
332    pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
333
334    /// 1/sqrt(π)
335    #[unstable(feature = "more_float_constants", issue = "146939")]
336    pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
337
338    /// 1/sqrt(2π)
339    #[doc(alias = "FRAC_1_SQRT_TAU")]
340    #[unstable(feature = "more_float_constants", issue = "146939")]
341    pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
342
343    /// 2/π
344    #[stable(feature = "rust1", since = "1.0.0")]
345    pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32;
346
347    /// 2/sqrt(π)
348    #[stable(feature = "rust1", since = "1.0.0")]
349    pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32;
350
351    /// sqrt(2)
352    #[stable(feature = "rust1", since = "1.0.0")]
353    pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32;
354
355    /// 1/sqrt(2)
356    #[stable(feature = "rust1", since = "1.0.0")]
357    pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
358
359    /// sqrt(3)
360    #[unstable(feature = "more_float_constants", issue = "146939")]
361    pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
362
363    /// 1/sqrt(3)
364    #[unstable(feature = "more_float_constants", issue = "146939")]
365    pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
366
367    /// Euler's number (e)
368    #[stable(feature = "rust1", since = "1.0.0")]
369    pub const E: f32 = 2.71828182845904523536028747135266250_f32;
370
371    /// log<sub>2</sub>(e)
372    #[stable(feature = "rust1", since = "1.0.0")]
373    pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
374
375    /// log<sub>2</sub>(10)
376    #[stable(feature = "extra_log_consts", since = "1.43.0")]
377    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
378
379    /// log<sub>10</sub>(e)
380    #[stable(feature = "rust1", since = "1.0.0")]
381    pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
382
383    /// log<sub>10</sub>(2)
384    #[stable(feature = "extra_log_consts", since = "1.43.0")]
385    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
386
387    /// ln(2)
388    #[stable(feature = "rust1", since = "1.0.0")]
389    pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;
390
391    /// ln(10)
392    #[stable(feature = "rust1", since = "1.0.0")]
393    pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
394}
395
396impl f32 {
397    /// The radix or base of the internal representation of `f32`.
398    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
399    pub const RADIX: u32 = 2;
400
401    /// Number of significant digits in base 2.
402    ///
403    /// Note that the size of the mantissa in the bitwise representation is one
404    /// smaller than this since the leading 1 is not stored explicitly.
405    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
406    pub const MANTISSA_DIGITS: u32 = 24;
407
408    /// Approximate number of significant digits in base 10.
409    ///
410    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
411    /// significant digits can be converted to `f32` and back without loss.
412    ///
413    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
414    ///
415    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
416    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
417    pub const DIGITS: u32 = 6;
418
419    /// [Machine epsilon] value for `f32`.
420    ///
421    /// This is the difference between `1.0` and the next larger representable number.
422    ///
423    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
424    ///
425    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
426    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
427    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
428    #[rustc_diagnostic_item = "f32_epsilon"]
429    pub const EPSILON: f32 = 1.19209290e-07_f32;
430
431    /// Smallest finite `f32` value.
432    ///
433    /// Equal to &minus;[`MAX`].
434    ///
435    /// [`MAX`]: f32::MAX
436    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
437    pub const MIN: f32 = -3.40282347e+38_f32;
438    /// Smallest positive normal `f32` value.
439    ///
440    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
441    ///
442    /// [`MIN_EXP`]: f32::MIN_EXP
443    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
444    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
445    /// Largest finite `f32` value.
446    ///
447    /// Equal to
448    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
449    ///
450    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
451    /// [`MAX_EXP`]: f32::MAX_EXP
452    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
453    pub const MAX: f32 = 3.40282347e+38_f32;
454
455    /// One greater than the minimum possible *normal* power of 2 exponent
456    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
457    ///
458    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
459    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
460    /// In other words, all normal numbers representable by this type are
461    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
462    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
463    pub const MIN_EXP: i32 = -125;
464    /// One greater than the maximum possible power of 2 exponent
465    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
466    ///
467    /// This corresponds to the exact maximum possible power of 2 exponent
468    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
469    /// In other words, all numbers representable by this type are
470    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
471    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
472    pub const MAX_EXP: i32 = 128;
473
474    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
475    ///
476    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
477    ///
478    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
479    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
480    pub const MIN_10_EXP: i32 = -37;
481    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
482    ///
483    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
484    ///
485    /// [`MAX`]: f32::MAX
486    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
487    pub const MAX_10_EXP: i32 = 38;
488
489    /// Not a Number (NaN).
490    ///
491    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
492    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
493    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
494    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
495    /// info.
496    ///
497    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
498    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
499    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
500    /// The concrete bit pattern may change across Rust versions and target platforms.
501    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
502    #[rustc_diagnostic_item = "f32_nan"]
503    #[allow(clippy::eq_op)]
504    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
505    /// Infinity (∞).
506    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
507    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
508    /// Negative infinity (−∞).
509    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
510    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
511
512    /// Sign bit
513    #[cfg(not(feature = "ferrocene_subset"))]
514    pub(crate) const SIGN_MASK: u32 = 0x8000_0000;
515
516    /// Exponent mask
517    pub(crate) const EXP_MASK: u32 = 0x7f80_0000;
518
519    /// Mantissa mask
520    pub(crate) const MAN_MASK: u32 = 0x007f_ffff;
521
522    /// Minimum representable positive value (min subnormal)
523    #[cfg(not(feature = "ferrocene_subset"))]
524    const TINY_BITS: u32 = 0x1;
525
526    /// Minimum representable negative value (min negative subnormal)
527    #[cfg(not(feature = "ferrocene_subset"))]
528    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
529
530    /// Returns `true` if this value is NaN.
531    ///
532    /// ```
533    /// let nan = f32::NAN;
534    /// let f = 7.0_f32;
535    ///
536    /// assert!(nan.is_nan());
537    /// assert!(!f.is_nan());
538    /// ```
539    #[must_use]
540    #[stable(feature = "rust1", since = "1.0.0")]
541    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
542    #[inline]
543    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
544    pub const fn is_nan(self) -> bool {
545        self != self
546    }
547
548    /// Returns `true` if this value is positive infinity or negative infinity, and
549    /// `false` otherwise.
550    ///
551    /// ```
552    /// let f = 7.0f32;
553    /// let inf = f32::INFINITY;
554    /// let neg_inf = f32::NEG_INFINITY;
555    /// let nan = f32::NAN;
556    ///
557    /// assert!(!f.is_infinite());
558    /// assert!(!nan.is_infinite());
559    ///
560    /// assert!(inf.is_infinite());
561    /// assert!(neg_inf.is_infinite());
562    /// ```
563    #[must_use]
564    #[stable(feature = "rust1", since = "1.0.0")]
565    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
566    #[inline]
567    pub const fn is_infinite(self) -> bool {
568        // Getting clever with transmutation can result in incorrect answers on some FPUs
569        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
570        // See https://github.com/rust-lang/rust/issues/72327
571        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
572    }
573
574    /// Returns `true` if this number is neither infinite nor NaN.
575    ///
576    /// ```
577    /// let f = 7.0f32;
578    /// let inf = f32::INFINITY;
579    /// let neg_inf = f32::NEG_INFINITY;
580    /// let nan = f32::NAN;
581    ///
582    /// assert!(f.is_finite());
583    ///
584    /// assert!(!nan.is_finite());
585    /// assert!(!inf.is_finite());
586    /// assert!(!neg_inf.is_finite());
587    /// ```
588    #[must_use]
589    #[stable(feature = "rust1", since = "1.0.0")]
590    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
591    #[inline]
592    #[cfg(not(feature = "ferrocene_subset"))]
593    pub const fn is_finite(self) -> bool {
594        // There's no need to handle NaN separately: if self is NaN,
595        // the comparison is not true, exactly as desired.
596        self.abs() < Self::INFINITY
597    }
598
599    /// Returns `true` if the number is [subnormal].
600    ///
601    /// ```
602    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
603    /// let max = f32::MAX;
604    /// let lower_than_min = 1.0e-40_f32;
605    /// let zero = 0.0_f32;
606    ///
607    /// assert!(!min.is_subnormal());
608    /// assert!(!max.is_subnormal());
609    ///
610    /// assert!(!zero.is_subnormal());
611    /// assert!(!f32::NAN.is_subnormal());
612    /// assert!(!f32::INFINITY.is_subnormal());
613    /// // Values between `0` and `min` are Subnormal.
614    /// assert!(lower_than_min.is_subnormal());
615    /// ```
616    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
617    #[must_use]
618    #[stable(feature = "is_subnormal", since = "1.53.0")]
619    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
620    #[inline]
621    #[cfg(not(feature = "ferrocene_subset"))]
622    pub const fn is_subnormal(self) -> bool {
623        matches!(self.classify(), FpCategory::Subnormal)
624    }
625
626    /// Returns `true` if the number is neither zero, infinite,
627    /// [subnormal], or NaN.
628    ///
629    /// ```
630    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
631    /// let max = f32::MAX;
632    /// let lower_than_min = 1.0e-40_f32;
633    /// let zero = 0.0_f32;
634    ///
635    /// assert!(min.is_normal());
636    /// assert!(max.is_normal());
637    ///
638    /// assert!(!zero.is_normal());
639    /// assert!(!f32::NAN.is_normal());
640    /// assert!(!f32::INFINITY.is_normal());
641    /// // Values between `0` and `min` are Subnormal.
642    /// assert!(!lower_than_min.is_normal());
643    /// ```
644    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
645    #[must_use]
646    #[stable(feature = "rust1", since = "1.0.0")]
647    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
648    #[inline]
649    #[cfg(not(feature = "ferrocene_subset"))]
650    pub const fn is_normal(self) -> bool {
651        matches!(self.classify(), FpCategory::Normal)
652    }
653
654    /// Returns the floating point category of the number. If only one property
655    /// is going to be tested, it is generally faster to use the specific
656    /// predicate instead.
657    ///
658    /// ```
659    /// use std::num::FpCategory;
660    ///
661    /// let num = 12.4_f32;
662    /// let inf = f32::INFINITY;
663    ///
664    /// assert_eq!(num.classify(), FpCategory::Normal);
665    /// assert_eq!(inf.classify(), FpCategory::Infinite);
666    /// ```
667    #[stable(feature = "rust1", since = "1.0.0")]
668    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
669    pub const fn classify(self) -> FpCategory {
670        // We used to have complicated logic here that avoids the simple bit-based tests to work
671        // around buggy codegen for x87 targets (see
672        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
673        // of our tests is able to find any difference between the complicated and the naive
674        // version, so now we are back to the naive version.
675        let b = self.to_bits();
676        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
677            (0, Self::EXP_MASK) => FpCategory::Infinite,
678            (_, Self::EXP_MASK) => FpCategory::Nan,
679            (0, 0) => FpCategory::Zero,
680            (_, 0) => FpCategory::Subnormal,
681            _ => FpCategory::Normal,
682        }
683    }
684
685    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
686    /// positive sign bit and positive infinity.
687    ///
688    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
689    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
690    /// conserved over arithmetic operations, the result of `is_sign_positive` on
691    /// a NaN might produce an unexpected or non-portable result. See the [specification
692    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
693    /// if you need fully portable behavior (will return `false` for all NaNs).
694    ///
695    /// ```
696    /// let f = 7.0_f32;
697    /// let g = -7.0_f32;
698    ///
699    /// assert!(f.is_sign_positive());
700    /// assert!(!g.is_sign_positive());
701    /// ```
702    #[must_use]
703    #[stable(feature = "rust1", since = "1.0.0")]
704    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
705    #[inline]
706    #[cfg(not(feature = "ferrocene_subset"))]
707    pub const fn is_sign_positive(self) -> bool {
708        !self.is_sign_negative()
709    }
710
711    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
712    /// negative sign bit and negative infinity.
713    ///
714    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
715    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
716    /// conserved over arithmetic operations, the result of `is_sign_negative` on
717    /// a NaN might produce an unexpected or non-portable result. See the [specification
718    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
719    /// if you need fully portable behavior (will return `false` for all NaNs).
720    ///
721    /// ```
722    /// let f = 7.0f32;
723    /// let g = -7.0f32;
724    ///
725    /// assert!(!f.is_sign_negative());
726    /// assert!(g.is_sign_negative());
727    /// ```
728    #[must_use]
729    #[stable(feature = "rust1", since = "1.0.0")]
730    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
731    #[inline]
732    pub const fn is_sign_negative(self) -> bool {
733        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
734        // applies to zeros and NaNs as well.
735        self.to_bits() & 0x8000_0000 != 0
736    }
737
738    /// Returns the least number greater than `self`.
739    ///
740    /// Let `TINY` be the smallest representable positive `f32`. Then,
741    ///  - if `self.is_nan()`, this returns `self`;
742    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
743    ///  - if `self` is `-TINY`, this returns -0.0;
744    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
745    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
746    ///  - otherwise the unique least value greater than `self` is returned.
747    ///
748    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
749    /// is finite `x == x.next_up().next_down()` also holds.
750    ///
751    /// ```rust
752    /// // f32::EPSILON is the difference between 1.0 and the next number up.
753    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
754    /// // But not for most numbers.
755    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
756    /// assert_eq!(16777216f32.next_up(), 16777218.0);
757    /// ```
758    ///
759    /// This operation corresponds to IEEE-754 `nextUp`.
760    ///
761    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
762    /// [`INFINITY`]: Self::INFINITY
763    /// [`MIN`]: Self::MIN
764    /// [`MAX`]: Self::MAX
765    #[inline]
766    #[doc(alias = "nextUp")]
767    #[stable(feature = "float_next_up_down", since = "1.86.0")]
768    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
769    #[cfg(not(feature = "ferrocene_subset"))]
770    pub const fn next_up(self) -> Self {
771        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
772        // denormals to zero. This is in general unsound and unsupported, but here
773        // we do our best to still produce the correct result on such targets.
774        let bits = self.to_bits();
775        if self.is_nan() || bits == Self::INFINITY.to_bits() {
776            return self;
777        }
778
779        let abs = bits & !Self::SIGN_MASK;
780        let next_bits = if abs == 0 {
781            Self::TINY_BITS
782        } else if bits == abs {
783            bits + 1
784        } else {
785            bits - 1
786        };
787        Self::from_bits(next_bits)
788    }
789
790    /// Returns the greatest number less than `self`.
791    ///
792    /// Let `TINY` be the smallest representable positive `f32`. Then,
793    ///  - if `self.is_nan()`, this returns `self`;
794    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
795    ///  - if `self` is `TINY`, this returns 0.0;
796    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
797    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
798    ///  - otherwise the unique greatest value less than `self` is returned.
799    ///
800    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
801    /// is finite `x == x.next_down().next_up()` also holds.
802    ///
803    /// ```rust
804    /// let x = 1.0f32;
805    /// // Clamp value into range [0, 1).
806    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
807    /// assert!(clamped < 1.0);
808    /// assert_eq!(clamped.next_up(), 1.0);
809    /// ```
810    ///
811    /// This operation corresponds to IEEE-754 `nextDown`.
812    ///
813    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
814    /// [`INFINITY`]: Self::INFINITY
815    /// [`MIN`]: Self::MIN
816    /// [`MAX`]: Self::MAX
817    #[inline]
818    #[doc(alias = "nextDown")]
819    #[stable(feature = "float_next_up_down", since = "1.86.0")]
820    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
821    #[cfg(not(feature = "ferrocene_subset"))]
822    pub const fn next_down(self) -> Self {
823        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
824        // denormals to zero. This is in general unsound and unsupported, but here
825        // we do our best to still produce the correct result on such targets.
826        let bits = self.to_bits();
827        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
828            return self;
829        }
830
831        let abs = bits & !Self::SIGN_MASK;
832        let next_bits = if abs == 0 {
833            Self::NEG_TINY_BITS
834        } else if bits == abs {
835            bits - 1
836        } else {
837            bits + 1
838        };
839        Self::from_bits(next_bits)
840    }
841
842    /// Takes the reciprocal (inverse) of a number, `1/x`.
843    ///
844    /// ```
845    /// let x = 2.0_f32;
846    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
847    ///
848    /// assert!(abs_difference <= f32::EPSILON);
849    /// ```
850    #[must_use = "this returns the result of the operation, without modifying the original"]
851    #[stable(feature = "rust1", since = "1.0.0")]
852    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
853    #[inline]
854    #[cfg(not(feature = "ferrocene_subset"))]
855    pub const fn recip(self) -> f32 {
856        1.0 / self
857    }
858
859    /// Converts radians to degrees.
860    ///
861    /// # Unspecified precision
862    ///
863    /// The precision of this function is non-deterministic. This means it varies by platform,
864    /// Rust version, and can even differ within the same execution from one invocation to the next.
865    ///
866    /// # Examples
867    ///
868    /// ```
869    /// let angle = std::f32::consts::PI;
870    ///
871    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
872    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
873    /// assert!(abs_difference <= f32::EPSILON);
874    /// ```
875    #[must_use = "this returns the result of the operation, \
876                  without modifying the original"]
877    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
878    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
879    #[inline]
880    #[cfg(not(feature = "ferrocene_subset"))]
881    pub const fn to_degrees(self) -> f32 {
882        // Use a literal to avoid double rounding, consts::PI is already rounded,
883        // and dividing would round again.
884        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
885        self * PIS_IN_180
886    }
887
888    /// Converts degrees to radians.
889    ///
890    /// # Unspecified precision
891    ///
892    /// The precision of this function is non-deterministic. This means it varies by platform,
893    /// Rust version, and can even differ within the same execution from one invocation to the next.
894    ///
895    /// # Examples
896    ///
897    /// ```
898    /// let angle = 180.0f32;
899    ///
900    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
901    ///
902    /// assert!(abs_difference <= f32::EPSILON);
903    /// ```
904    #[must_use = "this returns the result of the operation, \
905                  without modifying the original"]
906    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
907    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
908    #[inline]
909    #[cfg(not(feature = "ferrocene_subset"))]
910    pub const fn to_radians(self) -> f32 {
911        // The division here is correctly rounded with respect to the true value of π/180.
912        // Although π is irrational and already rounded, the double rounding happens
913        // to produce correct result for f32.
914        const RADS_PER_DEG: f32 = consts::PI / 180.0;
915        self * RADS_PER_DEG
916    }
917
918    /// Returns the maximum of the two numbers, ignoring NaN.
919    ///
920    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
921    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
922    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
923    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
924    /// non-deterministically.
925    ///
926    /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all
927    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
928    /// follows the IEEE 754-2008 semantics for `maxNum`.
929    ///
930    /// ```
931    /// let x = 1.0f32;
932    /// let y = 2.0f32;
933    ///
934    /// assert_eq!(x.max(y), y);
935    /// assert_eq!(x.max(f32::NAN), x);
936    /// ```
937    #[must_use = "this returns the result of the comparison, without modifying either input"]
938    #[stable(feature = "rust1", since = "1.0.0")]
939    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
940    #[inline]
941    pub const fn max(self, other: f32) -> f32 {
942        intrinsics::maxnumf32(self, other)
943    }
944
945    /// Returns the minimum of the two numbers, ignoring NaN.
946    ///
947    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
948    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
949    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
950    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
951    /// non-deterministically.
952    ///
953    /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all
954    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
955    /// follows the IEEE 754-2008 semantics for `minNum`.
956    ///
957    /// ```
958    /// let x = 1.0f32;
959    /// let y = 2.0f32;
960    ///
961    /// assert_eq!(x.min(y), x);
962    /// assert_eq!(x.min(f32::NAN), x);
963    /// ```
964    #[must_use = "this returns the result of the comparison, without modifying either input"]
965    #[stable(feature = "rust1", since = "1.0.0")]
966    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
967    #[inline]
968    pub const fn min(self, other: f32) -> f32 {
969        intrinsics::minnumf32(self, other)
970    }
971
972    /// Returns the maximum of the two numbers, propagating NaN.
973    ///
974    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
975    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
976    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
977    /// non-NaN inputs.
978    ///
979    /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN,
980    /// and which does not reliably order `-0.0` and `+0.0`.
981    ///
982    /// This follows the IEEE 754-2019 semantics for `maximum`.
983    ///
984    /// ```
985    /// #![feature(float_minimum_maximum)]
986    /// let x = 1.0f32;
987    /// let y = 2.0f32;
988    ///
989    /// assert_eq!(x.maximum(y), y);
990    /// assert!(x.maximum(f32::NAN).is_nan());
991    /// ```
992    #[must_use = "this returns the result of the comparison, without modifying either input"]
993    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
994    #[inline]
995    #[cfg(not(feature = "ferrocene_subset"))]
996    pub const fn maximum(self, other: f32) -> f32 {
997        intrinsics::maximumf32(self, other)
998    }
999
1000    /// Returns the minimum of the two numbers, propagating NaN.
1001    ///
1002    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1003    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1004    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1005    /// non-NaN inputs.
1006    ///
1007    /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN,
1008    /// and which does not reliably order `-0.0` and `+0.0`.
1009    ///
1010    /// This follows the IEEE 754-2019 semantics for `minimum`.
1011    ///
1012    /// ```
1013    /// #![feature(float_minimum_maximum)]
1014    /// let x = 1.0f32;
1015    /// let y = 2.0f32;
1016    ///
1017    /// assert_eq!(x.minimum(y), x);
1018    /// assert!(x.minimum(f32::NAN).is_nan());
1019    /// ```
1020    #[must_use = "this returns the result of the comparison, without modifying either input"]
1021    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1022    #[inline]
1023    #[cfg(not(feature = "ferrocene_subset"))]
1024    pub const fn minimum(self, other: f32) -> f32 {
1025        intrinsics::minimumf32(self, other)
1026    }
1027
1028    /// Calculates the midpoint (average) between `self` and `rhs`.
1029    ///
1030    /// This returns NaN when *either* argument is NaN or if a combination of
1031    /// +inf and -inf is provided as arguments.
1032    ///
1033    /// # Examples
1034    ///
1035    /// ```
1036    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1037    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1038    /// ```
1039    #[inline]
1040    #[doc(alias = "average")]
1041    #[stable(feature = "num_midpoint", since = "1.85.0")]
1042    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1043    #[cfg(not(feature = "ferrocene_subset"))]
1044    pub const fn midpoint(self, other: f32) -> f32 {
1045        cfg_select! {
1046            // Allow faster implementation that have known good 64-bit float
1047            // implementations. Falling back to the branchy code on targets that don't
1048            // have 64-bit hardware floats or buggy implementations.
1049            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1050            any(
1051                target_arch = "x86_64",
1052                target_arch = "aarch64",
1053                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1054                all(target_arch = "loongarch64", target_feature = "d"),
1055                all(target_arch = "arm", target_feature = "vfp2"),
1056                target_arch = "wasm32",
1057                target_arch = "wasm64",
1058            ) => {
1059                ((self as f64 + other as f64) / 2.0) as f32
1060            }
1061            _ => {
1062                const HI: f32 = f32::MAX / 2.;
1063
1064                let (a, b) = (self, other);
1065                let abs_a = a.abs();
1066                let abs_b = b.abs();
1067
1068                if abs_a <= HI && abs_b <= HI {
1069                    // Overflow is impossible
1070                    (a + b) / 2.
1071                } else {
1072                    (a / 2.) + (b / 2.)
1073                }
1074            }
1075        }
1076    }
1077
1078    /// Rounds toward zero and converts to any primitive integer type,
1079    /// assuming that the value is finite and fits in that type.
1080    ///
1081    /// ```
1082    /// let value = 4.6_f32;
1083    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1084    /// assert_eq!(rounded, 4);
1085    ///
1086    /// let value = -128.9_f32;
1087    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1088    /// assert_eq!(rounded, i8::MIN);
1089    /// ```
1090    ///
1091    /// # Safety
1092    ///
1093    /// The value must:
1094    ///
1095    /// * Not be `NaN`
1096    /// * Not be infinite
1097    /// * Be representable in the return type `Int`, after truncating off its fractional part
1098    #[must_use = "this returns the result of the operation, \
1099                  without modifying the original"]
1100    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1101    #[inline]
1102    #[cfg(not(feature = "ferrocene_subset"))]
1103    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1104    where
1105        Self: FloatToInt<Int>,
1106    {
1107        // SAFETY: the caller must uphold the safety contract for
1108        // `FloatToInt::to_int_unchecked`.
1109        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1110    }
1111
1112    /// Raw transmutation to `u32`.
1113    ///
1114    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1115    ///
1116    /// See [`from_bits`](Self::from_bits) for some discussion of the
1117    /// portability of this operation (there are almost no issues).
1118    ///
1119    /// Note that this function is distinct from `as` casting, which attempts to
1120    /// preserve the *numeric* value, and not the bitwise value.
1121    ///
1122    /// # Examples
1123    ///
1124    /// ```
1125    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1126    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1127    ///
1128    /// ```
1129    #[must_use = "this returns the result of the operation, \
1130                  without modifying the original"]
1131    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1132    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1133    #[inline]
1134    #[allow(unnecessary_transmutes)]
1135    pub const fn to_bits(self) -> u32 {
1136        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1137        unsafe { mem::transmute(self) }
1138    }
1139
1140    /// Raw transmutation from `u32`.
1141    ///
1142    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1143    /// It turns out this is incredibly portable, for two reasons:
1144    ///
1145    /// * Floats and Ints have the same endianness on all supported platforms.
1146    /// * IEEE 754 very precisely specifies the bit layout of floats.
1147    ///
1148    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1149    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1150    /// (notably x86 and ARM) picked the interpretation that was ultimately
1151    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1152    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1153    ///
1154    /// Rather than trying to preserve signaling-ness cross-platform, this
1155    /// implementation favors preserving the exact bits. This means that
1156    /// any payloads encoded in NaNs will be preserved even if the result of
1157    /// this method is sent over the network from an x86 machine to a MIPS one.
1158    ///
1159    /// If the results of this method are only manipulated by the same
1160    /// architecture that produced them, then there is no portability concern.
1161    ///
1162    /// If the input isn't NaN, then there is no portability concern.
1163    ///
1164    /// If you don't care about signalingness (very likely), then there is no
1165    /// portability concern.
1166    ///
1167    /// Note that this function is distinct from `as` casting, which attempts to
1168    /// preserve the *numeric* value, and not the bitwise value.
1169    ///
1170    /// # Examples
1171    ///
1172    /// ```
1173    /// let v = f32::from_bits(0x41480000);
1174    /// assert_eq!(v, 12.5);
1175    /// ```
1176    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1177    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1178    #[must_use]
1179    #[inline]
1180    #[allow(unnecessary_transmutes)]
1181    pub const fn from_bits(v: u32) -> Self {
1182        // It turns out the safety issues with sNaN were overblown! Hooray!
1183        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1184        unsafe { mem::transmute(v) }
1185    }
1186
1187    /// Returns the memory representation of this floating point number as a byte array in
1188    /// big-endian (network) byte order.
1189    ///
1190    /// See [`from_bits`](Self::from_bits) for some discussion of the
1191    /// portability of this operation (there are almost no issues).
1192    ///
1193    /// # Examples
1194    ///
1195    /// ```
1196    /// let bytes = 12.5f32.to_be_bytes();
1197    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1198    /// ```
1199    #[must_use = "this returns the result of the operation, \
1200                  without modifying the original"]
1201    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1202    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1203    #[inline]
1204    #[cfg(not(feature = "ferrocene_subset"))]
1205    pub const fn to_be_bytes(self) -> [u8; 4] {
1206        self.to_bits().to_be_bytes()
1207    }
1208
1209    /// Returns the memory representation of this floating point number as a byte array in
1210    /// little-endian byte order.
1211    ///
1212    /// See [`from_bits`](Self::from_bits) for some discussion of the
1213    /// portability of this operation (there are almost no issues).
1214    ///
1215    /// # Examples
1216    ///
1217    /// ```
1218    /// let bytes = 12.5f32.to_le_bytes();
1219    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1220    /// ```
1221    #[must_use = "this returns the result of the operation, \
1222                  without modifying the original"]
1223    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1224    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1225    #[inline]
1226    pub const fn to_le_bytes(self) -> [u8; 4] {
1227        self.to_bits().to_le_bytes()
1228    }
1229
1230    /// Returns the memory representation of this floating point number as a byte array in
1231    /// native byte order.
1232    ///
1233    /// As the target platform's native endianness is used, portable code
1234    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1235    ///
1236    /// [`to_be_bytes`]: f32::to_be_bytes
1237    /// [`to_le_bytes`]: f32::to_le_bytes
1238    ///
1239    /// See [`from_bits`](Self::from_bits) for some discussion of the
1240    /// portability of this operation (there are almost no issues).
1241    ///
1242    /// # Examples
1243    ///
1244    /// ```
1245    /// let bytes = 12.5f32.to_ne_bytes();
1246    /// assert_eq!(
1247    ///     bytes,
1248    ///     if cfg!(target_endian = "big") {
1249    ///         [0x41, 0x48, 0x00, 0x00]
1250    ///     } else {
1251    ///         [0x00, 0x00, 0x48, 0x41]
1252    ///     }
1253    /// );
1254    /// ```
1255    #[must_use = "this returns the result of the operation, \
1256                  without modifying the original"]
1257    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1258    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1259    #[inline]
1260    #[cfg(not(feature = "ferrocene_subset"))]
1261    pub const fn to_ne_bytes(self) -> [u8; 4] {
1262        self.to_bits().to_ne_bytes()
1263    }
1264
1265    /// Creates a floating point value from its representation as a byte array in big endian.
1266    ///
1267    /// See [`from_bits`](Self::from_bits) for some discussion of the
1268    /// portability of this operation (there are almost no issues).
1269    ///
1270    /// # Examples
1271    ///
1272    /// ```
1273    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1274    /// assert_eq!(value, 12.5);
1275    /// ```
1276    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1277    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1278    #[must_use]
1279    #[inline]
1280    #[cfg(not(feature = "ferrocene_subset"))]
1281    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1282        Self::from_bits(u32::from_be_bytes(bytes))
1283    }
1284
1285    /// Creates a floating point value from its representation as a byte array in little endian.
1286    ///
1287    /// See [`from_bits`](Self::from_bits) for some discussion of the
1288    /// portability of this operation (there are almost no issues).
1289    ///
1290    /// # Examples
1291    ///
1292    /// ```
1293    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1294    /// assert_eq!(value, 12.5);
1295    /// ```
1296    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1297    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1298    #[must_use]
1299    #[inline]
1300    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1301        Self::from_bits(u32::from_le_bytes(bytes))
1302    }
1303
1304    /// Creates a floating point value from its representation as a byte array in native endian.
1305    ///
1306    /// As the target platform's native endianness is used, portable code
1307    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1308    /// appropriate instead.
1309    ///
1310    /// [`from_be_bytes`]: f32::from_be_bytes
1311    /// [`from_le_bytes`]: f32::from_le_bytes
1312    ///
1313    /// See [`from_bits`](Self::from_bits) for some discussion of the
1314    /// portability of this operation (there are almost no issues).
1315    ///
1316    /// # Examples
1317    ///
1318    /// ```
1319    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1320    ///     [0x41, 0x48, 0x00, 0x00]
1321    /// } else {
1322    ///     [0x00, 0x00, 0x48, 0x41]
1323    /// });
1324    /// assert_eq!(value, 12.5);
1325    /// ```
1326    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1327    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1328    #[must_use]
1329    #[inline]
1330    #[cfg(not(feature = "ferrocene_subset"))]
1331    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1332        Self::from_bits(u32::from_ne_bytes(bytes))
1333    }
1334
1335    /// Returns the ordering between `self` and `other`.
1336    ///
1337    /// Unlike the standard partial comparison between floating point numbers,
1338    /// this comparison always produces an ordering in accordance to
1339    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1340    /// floating point standard. The values are ordered in the following sequence:
1341    ///
1342    /// - negative quiet NaN
1343    /// - negative signaling NaN
1344    /// - negative infinity
1345    /// - negative numbers
1346    /// - negative subnormal numbers
1347    /// - negative zero
1348    /// - positive zero
1349    /// - positive subnormal numbers
1350    /// - positive numbers
1351    /// - positive infinity
1352    /// - positive signaling NaN
1353    /// - positive quiet NaN.
1354    ///
1355    /// The ordering established by this function does not always agree with the
1356    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1357    /// they consider negative and positive zero equal, while `total_cmp`
1358    /// doesn't.
1359    ///
1360    /// The interpretation of the signaling NaN bit follows the definition in
1361    /// the IEEE 754 standard, which may not match the interpretation by some of
1362    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1363    ///
1364    /// # Example
1365    ///
1366    /// ```
1367    /// struct GoodBoy {
1368    ///     name: String,
1369    ///     weight: f32,
1370    /// }
1371    ///
1372    /// let mut bois = vec![
1373    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1374    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1375    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1376    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1377    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1378    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1379    /// ];
1380    ///
1381    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1382    ///
1383    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1384    /// if f32::NAN.is_sign_negative() {
1385    ///     assert!(bois.into_iter().map(|b| b.weight)
1386    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1387    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1388    /// } else {
1389    ///     assert!(bois.into_iter().map(|b| b.weight)
1390    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1391    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1392    /// }
1393    /// ```
1394    #[stable(feature = "total_cmp", since = "1.62.0")]
1395    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1396    #[must_use]
1397    #[inline]
1398    #[cfg(not(feature = "ferrocene_subset"))]
1399    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1400        let mut left = self.to_bits() as i32;
1401        let mut right = other.to_bits() as i32;
1402
1403        // In case of negatives, flip all the bits except the sign
1404        // to achieve a similar layout as two's complement integers
1405        //
1406        // Why does this work? IEEE 754 floats consist of three fields:
1407        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1408        // fields as a whole have the property that their bitwise order is
1409        // equal to the numeric magnitude where the magnitude is defined.
1410        // The magnitude is not normally defined on NaN values, but
1411        // IEEE 754 totalOrder defines the NaN values also to follow the
1412        // bitwise order. This leads to order explained in the doc comment.
1413        // However, the representation of magnitude is the same for negative
1414        // and positive numbers – only the sign bit is different.
1415        // To easily compare the floats as signed integers, we need to
1416        // flip the exponent and mantissa bits in case of negative numbers.
1417        // We effectively convert the numbers to "two's complement" form.
1418        //
1419        // To do the flipping, we construct a mask and XOR against it.
1420        // We branchlessly calculate an "all-ones except for the sign bit"
1421        // mask from negative-signed values: right shifting sign-extends
1422        // the integer, so we "fill" the mask with sign bits, and then
1423        // convert to unsigned to push one more zero bit.
1424        // On positive values, the mask is all zeros, so it's a no-op.
1425        left ^= (((left >> 31) as u32) >> 1) as i32;
1426        right ^= (((right >> 31) as u32) >> 1) as i32;
1427
1428        left.cmp(&right)
1429    }
1430
1431    /// Restrict a value to a certain interval unless it is NaN.
1432    ///
1433    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1434    /// less than `min`. Otherwise this returns `self`.
1435    ///
1436    /// Note that this function returns NaN if the initial value was NaN as
1437    /// well. If the result is zero and among the three inputs `self`, `min`, and `max` there are
1438    /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically.
1439    ///
1440    /// # Panics
1441    ///
1442    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1443    ///
1444    /// # Examples
1445    ///
1446    /// ```
1447    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1448    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1449    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1450    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1451    ///
1452    /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic.
1453    /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0);
1454    /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0);
1455    /// // This is definitely a negative zero.
1456    /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative());
1457    /// ```
1458    #[must_use = "method returns a new number and does not mutate the original value"]
1459    #[stable(feature = "clamp", since = "1.50.0")]
1460    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1461    #[inline]
1462    #[cfg(not(feature = "ferrocene_subset"))]
1463    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1464        const_assert!(
1465            min <= max,
1466            "min > max, or either was NaN",
1467            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1468            min: f32,
1469            max: f32,
1470        );
1471
1472        if self < min {
1473            self = min;
1474        }
1475        if self > max {
1476            self = max;
1477        }
1478        self
1479    }
1480
1481    /// Clamps this number to a symmetric range centered around zero.
1482    ///
1483    /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
1484    ///
1485    /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
1486    /// explicit about the intent.
1487    ///
1488    /// # Panics
1489    ///
1490    /// Panics if `limit` is negative or NaN, as this indicates a logic error.
1491    ///
1492    /// # Examples
1493    ///
1494    /// ```
1495    /// #![feature(clamp_magnitude)]
1496    /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0);
1497    /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0);
1498    /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0);
1499    /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0);
1500    /// ```
1501    #[cfg(not(feature = "ferrocene_subset"))]
1502    #[must_use = "this returns the clamped value and does not modify the original"]
1503    #[unstable(feature = "clamp_magnitude", issue = "148519")]
1504    #[inline]
1505    pub fn clamp_magnitude(self, limit: f32) -> f32 {
1506        assert!(limit >= 0.0, "limit must be non-negative");
1507        let limit = limit.abs(); // Canonicalises -0.0 to 0.0
1508        self.clamp(-limit, limit)
1509    }
1510
1511    /// Computes the absolute value of `self`.
1512    ///
1513    /// This function always returns the precise result.
1514    ///
1515    /// # Examples
1516    ///
1517    /// ```
1518    /// let x = 3.5_f32;
1519    /// let y = -3.5_f32;
1520    ///
1521    /// assert_eq!(x.abs(), x);
1522    /// assert_eq!(y.abs(), -y);
1523    ///
1524    /// assert!(f32::NAN.abs().is_nan());
1525    /// ```
1526    #[must_use = "method returns a new number and does not mutate the original value"]
1527    #[stable(feature = "rust1", since = "1.0.0")]
1528    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1529    #[inline]
1530    pub const fn abs(self) -> f32 {
1531        intrinsics::fabsf32(self)
1532    }
1533
1534    /// Returns a number that represents the sign of `self`.
1535    ///
1536    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1537    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1538    /// - NaN if the number is NaN
1539    ///
1540    /// # Examples
1541    ///
1542    /// ```
1543    /// let f = 3.5_f32;
1544    ///
1545    /// assert_eq!(f.signum(), 1.0);
1546    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1547    ///
1548    /// assert!(f32::NAN.signum().is_nan());
1549    /// ```
1550    #[must_use = "method returns a new number and does not mutate the original value"]
1551    #[stable(feature = "rust1", since = "1.0.0")]
1552    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1553    #[inline]
1554    pub const fn signum(self) -> f32 {
1555        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1556    }
1557
1558    /// Returns a number composed of the magnitude of `self` and the sign of
1559    /// `sign`.
1560    ///
1561    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1562    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1563    /// returned.
1564    ///
1565    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1566    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1567    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1568    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1569    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1570    /// info.
1571    ///
1572    /// # Examples
1573    ///
1574    /// ```
1575    /// let f = 3.5_f32;
1576    ///
1577    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1578    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1579    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1580    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1581    ///
1582    /// assert!(f32::NAN.copysign(1.0).is_nan());
1583    /// ```
1584    #[must_use = "method returns a new number and does not mutate the original value"]
1585    #[inline]
1586    #[stable(feature = "copysign", since = "1.35.0")]
1587    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1588    pub const fn copysign(self, sign: f32) -> f32 {
1589        intrinsics::copysignf32(self, sign)
1590    }
1591
1592    /// Float addition that allows optimizations based on algebraic rules.
1593    ///
1594    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1595    #[must_use = "method returns a new number and does not mutate the original value"]
1596    #[unstable(feature = "float_algebraic", issue = "136469")]
1597    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1598    #[inline]
1599    #[cfg(not(feature = "ferrocene_subset"))]
1600    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1601        intrinsics::fadd_algebraic(self, rhs)
1602    }
1603
1604    /// Float subtraction that allows optimizations based on algebraic rules.
1605    ///
1606    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1607    #[must_use = "method returns a new number and does not mutate the original value"]
1608    #[unstable(feature = "float_algebraic", issue = "136469")]
1609    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1610    #[inline]
1611    #[cfg(not(feature = "ferrocene_subset"))]
1612    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1613        intrinsics::fsub_algebraic(self, rhs)
1614    }
1615
1616    /// Float multiplication that allows optimizations based on algebraic rules.
1617    ///
1618    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1619    #[must_use = "method returns a new number and does not mutate the original value"]
1620    #[unstable(feature = "float_algebraic", issue = "136469")]
1621    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1622    #[inline]
1623    #[cfg(not(feature = "ferrocene_subset"))]
1624    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1625        intrinsics::fmul_algebraic(self, rhs)
1626    }
1627
1628    /// Float division that allows optimizations based on algebraic rules.
1629    ///
1630    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1631    #[must_use = "method returns a new number and does not mutate the original value"]
1632    #[unstable(feature = "float_algebraic", issue = "136469")]
1633    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1634    #[inline]
1635    #[cfg(not(feature = "ferrocene_subset"))]
1636    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1637        intrinsics::fdiv_algebraic(self, rhs)
1638    }
1639
1640    /// Float remainder that allows optimizations based on algebraic rules.
1641    ///
1642    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1643    #[must_use = "method returns a new number and does not mutate the original value"]
1644    #[unstable(feature = "float_algebraic", issue = "136469")]
1645    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1646    #[inline]
1647    #[cfg(not(feature = "ferrocene_subset"))]
1648    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1649        intrinsics::frem_algebraic(self, rhs)
1650    }
1651}
1652
1653/// Experimental implementations of floating point functions in `core`.
1654///
1655/// _The standalone functions in this module are for testing only.
1656/// They will be stabilized as inherent methods._
1657#[unstable(feature = "core_float_math", issue = "137578")]
1658#[cfg(not(feature = "ferrocene_subset"))]
1659pub mod math {
1660    use crate::intrinsics;
1661    use crate::num::libm;
1662
1663    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1664    ///
1665    /// # Examples
1666    ///
1667    /// ```
1668    /// #![feature(core_float_math)]
1669    ///
1670    /// use core::f32;
1671    ///
1672    /// let f = 3.7_f32;
1673    /// let g = 3.0_f32;
1674    /// let h = -3.7_f32;
1675    ///
1676    /// assert_eq!(f32::math::floor(f), 3.0);
1677    /// assert_eq!(f32::math::floor(g), 3.0);
1678    /// assert_eq!(f32::math::floor(h), -4.0);
1679    /// ```
1680    ///
1681    /// _This standalone function is for testing only.
1682    /// It will be stabilized as an inherent method._
1683    ///
1684    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
1685    #[inline]
1686    #[unstable(feature = "core_float_math", issue = "137578")]
1687    #[must_use = "method returns a new number and does not mutate the original value"]
1688    pub const fn floor(x: f32) -> f32 {
1689        intrinsics::floorf32(x)
1690    }
1691
1692    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1693    ///
1694    /// # Examples
1695    ///
1696    /// ```
1697    /// #![feature(core_float_math)]
1698    ///
1699    /// use core::f32;
1700    ///
1701    /// let f = 3.01_f32;
1702    /// let g = 4.0_f32;
1703    ///
1704    /// assert_eq!(f32::math::ceil(f), 4.0);
1705    /// assert_eq!(f32::math::ceil(g), 4.0);
1706    /// ```
1707    ///
1708    /// _This standalone function is for testing only.
1709    /// It will be stabilized as an inherent method._
1710    ///
1711    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1712    #[inline]
1713    #[doc(alias = "ceiling")]
1714    #[must_use = "method returns a new number and does not mutate the original value"]
1715    #[unstable(feature = "core_float_math", issue = "137578")]
1716    pub const fn ceil(x: f32) -> f32 {
1717        intrinsics::ceilf32(x)
1718    }
1719
1720    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1721    ///
1722    /// # Examples
1723    ///
1724    /// ```
1725    /// #![feature(core_float_math)]
1726    ///
1727    /// use core::f32;
1728    ///
1729    /// let f = 3.3_f32;
1730    /// let g = -3.3_f32;
1731    /// let h = -3.7_f32;
1732    /// let i = 3.5_f32;
1733    /// let j = 4.5_f32;
1734    ///
1735    /// assert_eq!(f32::math::round(f), 3.0);
1736    /// assert_eq!(f32::math::round(g), -3.0);
1737    /// assert_eq!(f32::math::round(h), -4.0);
1738    /// assert_eq!(f32::math::round(i), 4.0);
1739    /// assert_eq!(f32::math::round(j), 5.0);
1740    /// ```
1741    ///
1742    /// _This standalone function is for testing only.
1743    /// It will be stabilized as an inherent method._
1744    ///
1745    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1746    #[inline]
1747    #[unstable(feature = "core_float_math", issue = "137578")]
1748    #[must_use = "method returns a new number and does not mutate the original value"]
1749    pub const fn round(x: f32) -> f32 {
1750        intrinsics::roundf32(x)
1751    }
1752
1753    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1754    /// details.
1755    ///
1756    /// # Examples
1757    ///
1758    /// ```
1759    /// #![feature(core_float_math)]
1760    ///
1761    /// use core::f32;
1762    ///
1763    /// let f = 3.3_f32;
1764    /// let g = -3.3_f32;
1765    /// let h = 3.5_f32;
1766    /// let i = 4.5_f32;
1767    ///
1768    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1769    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1770    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1771    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1772    /// ```
1773    ///
1774    /// _This standalone function is for testing only.
1775    /// It will be stabilized as an inherent method._
1776    ///
1777    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1778    #[inline]
1779    #[unstable(feature = "core_float_math", issue = "137578")]
1780    #[must_use = "method returns a new number and does not mutate the original value"]
1781    pub const fn round_ties_even(x: f32) -> f32 {
1782        intrinsics::round_ties_even_f32(x)
1783    }
1784
1785    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1786    ///
1787    /// # Examples
1788    ///
1789    /// ```
1790    /// #![feature(core_float_math)]
1791    ///
1792    /// use core::f32;
1793    ///
1794    /// let f = 3.7_f32;
1795    /// let g = 3.0_f32;
1796    /// let h = -3.7_f32;
1797    ///
1798    /// assert_eq!(f32::math::trunc(f), 3.0);
1799    /// assert_eq!(f32::math::trunc(g), 3.0);
1800    /// assert_eq!(f32::math::trunc(h), -3.0);
1801    /// ```
1802    ///
1803    /// _This standalone function is for testing only.
1804    /// It will be stabilized as an inherent method._
1805    ///
1806    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1807    #[inline]
1808    #[doc(alias = "truncate")]
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 trunc(x: f32) -> f32 {
1812        intrinsics::truncf32(x)
1813    }
1814
1815    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1816    ///
1817    /// # Examples
1818    ///
1819    /// ```
1820    /// #![feature(core_float_math)]
1821    ///
1822    /// use core::f32;
1823    ///
1824    /// let x = 3.6_f32;
1825    /// let y = -3.6_f32;
1826    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1827    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1828    ///
1829    /// assert!(abs_difference_x <= f32::EPSILON);
1830    /// assert!(abs_difference_y <= f32::EPSILON);
1831    /// ```
1832    ///
1833    /// _This standalone function is for testing only.
1834    /// It will be stabilized as an inherent method._
1835    ///
1836    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1837    #[inline]
1838    #[unstable(feature = "core_float_math", issue = "137578")]
1839    #[must_use = "method returns a new number and does not mutate the original value"]
1840    pub const fn fract(x: f32) -> f32 {
1841        x - trunc(x)
1842    }
1843
1844    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1845    ///
1846    /// # Examples
1847    ///
1848    /// ```
1849    /// #![feature(core_float_math)]
1850    ///
1851    /// # // FIXME(#140515): mingw has an incorrect fma
1852    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1853    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1854    /// use core::f32;
1855    ///
1856    /// let m = 10.0_f32;
1857    /// let x = 4.0_f32;
1858    /// let b = 60.0_f32;
1859    ///
1860    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1861    /// assert_eq!(m * x + b, 100.0);
1862    ///
1863    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1864    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1865    /// let minus_one = -1.0_f32;
1866    ///
1867    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1868    /// assert_eq!(
1869    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1870    ///     -f32::EPSILON * f32::EPSILON
1871    /// );
1872    /// // Different rounding with the non-fused multiply and add.
1873    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1874    /// # }
1875    /// ```
1876    ///
1877    /// _This standalone function is for testing only.
1878    /// It will be stabilized as an inherent method._
1879    ///
1880    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1881    #[inline]
1882    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1883    #[must_use = "method returns a new number and does not mutate the original value"]
1884    #[unstable(feature = "core_float_math", issue = "137578")]
1885    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1886        intrinsics::fmaf32(x, y, z)
1887    }
1888
1889    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1890    ///
1891    /// # Examples
1892    ///
1893    /// ```
1894    /// #![feature(core_float_math)]
1895    ///
1896    /// use core::f32;
1897    ///
1898    /// let a: f32 = 7.0;
1899    /// let b = 4.0;
1900    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
1901    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
1902    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
1903    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
1904    /// ```
1905    ///
1906    /// _This standalone function is for testing only.
1907    /// It will be stabilized as an inherent method._
1908    ///
1909    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
1910    #[inline]
1911    #[unstable(feature = "core_float_math", issue = "137578")]
1912    #[must_use = "method returns a new number and does not mutate the original value"]
1913    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
1914        let q = trunc(x / rhs);
1915        if x % rhs < 0.0 {
1916            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
1917        }
1918        q
1919    }
1920
1921    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
1922    ///
1923    /// # Examples
1924    ///
1925    /// ```
1926    /// #![feature(core_float_math)]
1927    ///
1928    /// use core::f32;
1929    ///
1930    /// let a: f32 = 7.0;
1931    /// let b = 4.0;
1932    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
1933    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
1934    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
1935    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
1936    /// // limitation due to round-off error
1937    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
1938    /// ```
1939    ///
1940    /// _This standalone function is for testing only.
1941    /// It will be stabilized as an inherent method._
1942    ///
1943    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
1944    #[inline]
1945    #[doc(alias = "modulo", alias = "mod")]
1946    #[unstable(feature = "core_float_math", issue = "137578")]
1947    #[must_use = "method returns a new number and does not mutate the original value"]
1948    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
1949        let r = x % rhs;
1950        if r < 0.0 { r + rhs.abs() } else { r }
1951    }
1952
1953    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
1954    ///
1955    /// # Examples
1956    ///
1957    /// ```
1958    /// #![feature(core_float_math)]
1959    ///
1960    /// use core::f32;
1961    ///
1962    /// let x = 2.0_f32;
1963    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
1964    /// assert!(abs_difference <= 1e-5);
1965    ///
1966    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
1967    /// ```
1968    ///
1969    /// _This standalone function is for testing only.
1970    /// It will be stabilized as an inherent method._
1971    ///
1972    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
1973    #[inline]
1974    #[must_use = "method returns a new number and does not mutate the original value"]
1975    #[unstable(feature = "core_float_math", issue = "137578")]
1976    pub fn powi(x: f32, n: i32) -> f32 {
1977        intrinsics::powif32(x, n)
1978    }
1979
1980    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
1981    ///
1982    /// # Examples
1983    ///
1984    /// ```
1985    /// #![feature(core_float_math)]
1986    ///
1987    /// use core::f32;
1988    ///
1989    /// let positive = 4.0_f32;
1990    /// let negative = -4.0_f32;
1991    /// let negative_zero = -0.0_f32;
1992    ///
1993    /// assert_eq!(f32::math::sqrt(positive), 2.0);
1994    /// assert!(f32::math::sqrt(negative).is_nan());
1995    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
1996    /// ```
1997    ///
1998    /// _This standalone function is for testing only.
1999    /// It will be stabilized as an inherent method._
2000    ///
2001    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
2002    #[inline]
2003    #[doc(alias = "squareRoot")]
2004    #[unstable(feature = "core_float_math", issue = "137578")]
2005    #[must_use = "method returns a new number and does not mutate the original value"]
2006    pub fn sqrt(x: f32) -> f32 {
2007        intrinsics::sqrtf32(x)
2008    }
2009
2010    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
2011    ///
2012    /// # Examples
2013    ///
2014    /// ```
2015    /// #![feature(core_float_math)]
2016    ///
2017    /// use core::f32;
2018    ///
2019    /// let x = 3.0f32;
2020    /// let y = -3.0f32;
2021    ///
2022    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
2023    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
2024    ///
2025    /// assert!(abs_difference_x <= 1e-6);
2026    /// assert!(abs_difference_y <= 1e-6);
2027    /// ```
2028    ///
2029    /// _This standalone function is for testing only.
2030    /// It will be stabilized as an inherent method._
2031    ///
2032    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
2033    #[inline]
2034    #[stable(feature = "rust1", since = "1.0.0")]
2035    #[deprecated(
2036        since = "1.10.0",
2037        note = "you probably meant `(self - other).abs()`: \
2038            this operation is `(self - other).max(0.0)` \
2039            except that `abs_sub` also propagates NaNs (also \
2040            known as `fdimf` in C). If you truly need the positive \
2041            difference, consider using that expression or the C function \
2042            `fdimf`, depending on how you wish to handle NaN (please consider \
2043            filing an issue describing your use-case too)."
2044    )]
2045    #[must_use = "method returns a new number and does not mutate the original value"]
2046    pub fn abs_sub(x: f32, other: f32) -> f32 {
2047        libm::fdimf(x, other)
2048    }
2049
2050    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
2051    ///
2052    /// # Unspecified precision
2053    ///
2054    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
2055    /// can even differ within the same execution from one invocation to the next.
2056    /// This function currently corresponds to the `cbrtf` from libc on Unix
2057    /// and Windows. Note that this might change in the future.
2058    ///
2059    /// # Examples
2060    ///
2061    /// ```
2062    /// #![feature(core_float_math)]
2063    ///
2064    /// use core::f32;
2065    ///
2066    /// let x = 8.0f32;
2067    ///
2068    /// // x^(1/3) - 2 == 0
2069    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
2070    ///
2071    /// assert!(abs_difference <= 1e-6);
2072    /// ```
2073    ///
2074    /// _This standalone function is for testing only.
2075    /// It will be stabilized as an inherent method._
2076    ///
2077    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
2078    #[inline]
2079    #[must_use = "method returns a new number and does not mutate the original value"]
2080    #[unstable(feature = "core_float_math", issue = "137578")]
2081    pub fn cbrt(x: f32) -> f32 {
2082        libm::cbrtf(x)
2083    }
2084}