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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    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
296    pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32;
297
298    /// The Euler-Mascheroni constant (γ)
299    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
300    pub const EULER_GAMMA: f32 = 0.577215664901532860606512090082402431_f32;
301
302    /// π/2
303    #[stable(feature = "rust1", since = "1.0.0")]
304    pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32;
305
306    /// π/3
307    #[stable(feature = "rust1", since = "1.0.0")]
308    pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32;
309
310    /// π/4
311    #[stable(feature = "rust1", since = "1.0.0")]
312    pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32;
313
314    /// π/6
315    #[stable(feature = "rust1", since = "1.0.0")]
316    pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32;
317
318    /// π/8
319    #[stable(feature = "rust1", since = "1.0.0")]
320    pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32;
321
322    /// 1/π
323    #[stable(feature = "rust1", since = "1.0.0")]
324    pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
325
326    /// 1/sqrt(π)
327    #[unstable(feature = "more_float_constants", issue = "146939")]
328    pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
329
330    /// 1/sqrt(2π)
331    #[doc(alias = "FRAC_1_SQRT_TAU")]
332    #[unstable(feature = "more_float_constants", issue = "146939")]
333    pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
334
335    /// 2/π
336    #[stable(feature = "rust1", since = "1.0.0")]
337    pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32;
338
339    /// 2/sqrt(π)
340    #[stable(feature = "rust1", since = "1.0.0")]
341    pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32;
342
343    /// sqrt(2)
344    #[stable(feature = "rust1", since = "1.0.0")]
345    pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32;
346
347    /// 1/sqrt(2)
348    #[stable(feature = "rust1", since = "1.0.0")]
349    pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
350
351    /// sqrt(3)
352    #[unstable(feature = "more_float_constants", issue = "146939")]
353    pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
354
355    /// 1/sqrt(3)
356    #[unstable(feature = "more_float_constants", issue = "146939")]
357    pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
358
359    /// sqrt(5)
360    #[unstable(feature = "more_float_constants", issue = "146939")]
361    pub const SQRT_5: f32 = 2.23606797749978969640917366873127623_f32;
362
363    /// 1/sqrt(5)
364    #[unstable(feature = "more_float_constants", issue = "146939")]
365    pub const FRAC_1_SQRT_5: f32 = 0.44721359549995793928183473374625524_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
396#[doc(test(attr(allow(unused_features))))]
397impl f32 {
398    /// The radix or base of the internal representation of `f32`.
399    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
400    pub const RADIX: u32 = 2;
401
402    /// The size of this float type in bits.
403    #[unstable(feature = "float_bits_const", issue = "151073")]
404    pub const BITS: u32 = 32;
405
406    /// Number of significant digits in base 2.
407    ///
408    /// Note that the size of the mantissa in the bitwise representation is one
409    /// smaller than this since the leading 1 is not stored explicitly.
410    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
411    pub const MANTISSA_DIGITS: u32 = 24;
412
413    /// Approximate number of significant digits in base 10.
414    ///
415    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
416    /// significant digits can be converted to `f32` and back without loss.
417    ///
418    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
419    ///
420    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
421    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
422    pub const DIGITS: u32 = 6;
423
424    /// [Machine epsilon] value for `f32`.
425    ///
426    /// This is the difference between `1.0` and the next larger representable number.
427    ///
428    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
429    ///
430    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
431    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
432    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
433    #[rustc_diagnostic_item = "f32_epsilon"]
434    pub const EPSILON: f32 = 1.19209290e-07_f32;
435
436    /// Smallest finite `f32` value.
437    ///
438    /// Equal to &minus;[`MAX`].
439    ///
440    /// [`MAX`]: f32::MAX
441    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
442    pub const MIN: f32 = -3.40282347e+38_f32;
443    /// Smallest positive normal `f32` value.
444    ///
445    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
446    ///
447    /// [`MIN_EXP`]: f32::MIN_EXP
448    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
449    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
450    /// Largest finite `f32` value.
451    ///
452    /// Equal to
453    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
454    ///
455    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
456    /// [`MAX_EXP`]: f32::MAX_EXP
457    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
458    pub const MAX: f32 = 3.40282347e+38_f32;
459
460    /// One greater than the minimum possible *normal* power of 2 exponent
461    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
462    ///
463    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
464    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
465    /// In other words, all normal numbers representable by this type are
466    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
467    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
468    pub const MIN_EXP: i32 = -125;
469    /// One greater than the maximum possible power of 2 exponent
470    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
471    ///
472    /// This corresponds to the exact maximum possible power of 2 exponent
473    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
474    /// In other words, all numbers representable by this type are
475    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
476    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
477    pub const MAX_EXP: i32 = 128;
478
479    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
480    ///
481    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
482    ///
483    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
484    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
485    pub const MIN_10_EXP: i32 = -37;
486    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
487    ///
488    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
489    ///
490    /// [`MAX`]: f32::MAX
491    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
492    pub const MAX_10_EXP: i32 = 38;
493
494    /// Not a Number (NaN).
495    ///
496    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
497    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
498    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
499    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
500    /// info.
501    ///
502    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
503    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
504    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
505    /// The concrete bit pattern may change across Rust versions and target platforms.
506    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
507    #[rustc_diagnostic_item = "f32_nan"]
508    #[allow(clippy::eq_op)]
509    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
510    /// Infinity (∞).
511    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
512    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
513    /// Negative infinity (−∞).
514    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
515    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
516
517    /// Maximum integer that can be represented exactly in an [`f32`] value,
518    /// with no other integer converting to the same floating point value.
519    ///
520    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
521    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
522    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
523    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
524    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
525    /// "one-to-one" mapping.
526    ///
527    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
528    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
529    /// ```
530    /// #![feature(float_exact_integer_constants)]
531    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
532    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
533    /// let max_exact_int = f32::MAX_EXACT_INTEGER;
534    /// assert_eq!(max_exact_int, max_exact_int as f32 as i32);
535    /// assert_eq!(max_exact_int + 1, (max_exact_int + 1) as f32 as i32);
536    /// assert_ne!(max_exact_int + 2, (max_exact_int + 2) as f32 as i32);
537    ///
538    /// // Beyond `f32::MAX_EXACT_INTEGER`, multiple integers can map to one float value
539    /// assert_eq!((max_exact_int + 1) as f32, (max_exact_int + 2) as f32);
540    /// # }
541    /// ```
542    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
543    pub const MAX_EXACT_INTEGER: i32 = (1 << Self::MANTISSA_DIGITS) - 1;
544
545    /// Minimum integer that can be represented exactly in an [`f32`] value,
546    /// with no other integer converting to the same floating point value.
547    ///
548    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
549    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
550    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
551    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
552    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
553    /// "one-to-one" mapping.
554    ///
555    /// This constant is equivalent to `-MAX_EXACT_INTEGER`.
556    ///
557    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
558    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
559    /// ```
560    /// #![feature(float_exact_integer_constants)]
561    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
562    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
563    /// let min_exact_int = f32::MIN_EXACT_INTEGER;
564    /// assert_eq!(min_exact_int, min_exact_int as f32 as i32);
565    /// assert_eq!(min_exact_int - 1, (min_exact_int - 1) as f32 as i32);
566    /// assert_ne!(min_exact_int - 2, (min_exact_int - 2) as f32 as i32);
567    ///
568    /// // Below `f32::MIN_EXACT_INTEGER`, multiple integers can map to one float value
569    /// assert_eq!((min_exact_int - 1) as f32, (min_exact_int - 2) as f32);
570    /// # }
571    /// ```
572    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
573    pub const MIN_EXACT_INTEGER: i32 = -Self::MAX_EXACT_INTEGER;
574
575    /// Sign bit
576    pub(crate) const SIGN_MASK: u32 = 0x8000_0000;
577
578    /// Exponent mask
579    pub(crate) const EXP_MASK: u32 = 0x7f80_0000;
580
581    /// Mantissa mask
582    pub(crate) const MAN_MASK: u32 = 0x007f_ffff;
583
584    /// Minimum representable positive value (min subnormal)
585    const TINY_BITS: u32 = 0x1;
586
587    /// Minimum representable negative value (min negative subnormal)
588    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
589
590    /// Returns `true` if this value is NaN.
591    ///
592    /// ```
593    /// let nan = f32::NAN;
594    /// let f = 7.0_f32;
595    ///
596    /// assert!(nan.is_nan());
597    /// assert!(!f.is_nan());
598    /// ```
599    #[must_use]
600    #[stable(feature = "rust1", since = "1.0.0")]
601    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
602    #[inline]
603    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
604    #[ferrocene::prevalidated]
605    pub const fn is_nan(self) -> bool {
606        self != self
607    }
608
609    /// Returns `true` if this value is positive infinity or negative infinity, and
610    /// `false` otherwise.
611    ///
612    /// ```
613    /// let f = 7.0f32;
614    /// let inf = f32::INFINITY;
615    /// let neg_inf = f32::NEG_INFINITY;
616    /// let nan = f32::NAN;
617    ///
618    /// assert!(!f.is_infinite());
619    /// assert!(!nan.is_infinite());
620    ///
621    /// assert!(inf.is_infinite());
622    /// assert!(neg_inf.is_infinite());
623    /// ```
624    #[must_use]
625    #[stable(feature = "rust1", since = "1.0.0")]
626    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
627    #[inline]
628    #[ferrocene::prevalidated]
629    pub const fn is_infinite(self) -> bool {
630        // Getting clever with transmutation can result in incorrect answers on some FPUs
631        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
632        // See https://github.com/rust-lang/rust/issues/72327
633        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
634    }
635
636    /// Returns `true` if this number is neither infinite nor NaN.
637    ///
638    /// ```
639    /// let f = 7.0f32;
640    /// let inf = f32::INFINITY;
641    /// let neg_inf = f32::NEG_INFINITY;
642    /// let nan = f32::NAN;
643    ///
644    /// assert!(f.is_finite());
645    ///
646    /// assert!(!nan.is_finite());
647    /// assert!(!inf.is_finite());
648    /// assert!(!neg_inf.is_finite());
649    /// ```
650    #[must_use]
651    #[stable(feature = "rust1", since = "1.0.0")]
652    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
653    #[inline]
654    pub const fn is_finite(self) -> bool {
655        // There's no need to handle NaN separately: if self is NaN,
656        // the comparison is not true, exactly as desired.
657        self.abs() < Self::INFINITY
658    }
659
660    /// Returns `true` if the number is [subnormal].
661    ///
662    /// ```
663    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
664    /// let max = f32::MAX;
665    /// let lower_than_min = 1.0e-40_f32;
666    /// let zero = 0.0_f32;
667    ///
668    /// assert!(!min.is_subnormal());
669    /// assert!(!max.is_subnormal());
670    ///
671    /// assert!(!zero.is_subnormal());
672    /// assert!(!f32::NAN.is_subnormal());
673    /// assert!(!f32::INFINITY.is_subnormal());
674    /// // Values between `0` and `min` are Subnormal.
675    /// assert!(lower_than_min.is_subnormal());
676    /// ```
677    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
678    #[must_use]
679    #[stable(feature = "is_subnormal", since = "1.53.0")]
680    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
681    #[inline]
682    pub const fn is_subnormal(self) -> bool {
683        matches!(self.classify(), FpCategory::Subnormal)
684    }
685
686    /// Returns `true` if the number is neither zero, infinite,
687    /// [subnormal], or NaN.
688    ///
689    /// ```
690    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
691    /// let max = f32::MAX;
692    /// let lower_than_min = 1.0e-40_f32;
693    /// let zero = 0.0_f32;
694    ///
695    /// assert!(min.is_normal());
696    /// assert!(max.is_normal());
697    ///
698    /// assert!(!zero.is_normal());
699    /// assert!(!f32::NAN.is_normal());
700    /// assert!(!f32::INFINITY.is_normal());
701    /// // Values between `0` and `min` are Subnormal.
702    /// assert!(!lower_than_min.is_normal());
703    /// ```
704    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
705    #[must_use]
706    #[stable(feature = "rust1", since = "1.0.0")]
707    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
708    #[inline]
709    pub const fn is_normal(self) -> bool {
710        matches!(self.classify(), FpCategory::Normal)
711    }
712
713    /// Returns the floating point category of the number. If only one property
714    /// is going to be tested, it is generally faster to use the specific
715    /// predicate instead.
716    ///
717    /// ```
718    /// use std::num::FpCategory;
719    ///
720    /// let num = 12.4_f32;
721    /// let inf = f32::INFINITY;
722    ///
723    /// assert_eq!(num.classify(), FpCategory::Normal);
724    /// assert_eq!(inf.classify(), FpCategory::Infinite);
725    /// ```
726    #[stable(feature = "rust1", since = "1.0.0")]
727    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
728    #[ferrocene::prevalidated]
729    pub const fn classify(self) -> FpCategory {
730        // We used to have complicated logic here that avoids the simple bit-based tests to work
731        // around buggy codegen for x87 targets (see
732        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
733        // of our tests is able to find any difference between the complicated and the naive
734        // version, so now we are back to the naive version.
735        let b = self.to_bits();
736        match (b & Self::MAN_MASK, b & Self::EXP_MASK) {
737            (0, Self::EXP_MASK) => FpCategory::Infinite,
738            (_, Self::EXP_MASK) => FpCategory::Nan,
739            (0, 0) => FpCategory::Zero,
740            (_, 0) => FpCategory::Subnormal,
741            _ => FpCategory::Normal,
742        }
743    }
744
745    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
746    /// positive sign bit and positive infinity.
747    ///
748    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
749    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
750    /// conserved over arithmetic operations, the result of `is_sign_positive` on
751    /// a NaN might produce an unexpected or non-portable result. See the [specification
752    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
753    /// if you need fully portable behavior (will return `false` for all NaNs).
754    ///
755    /// ```
756    /// let f = 7.0_f32;
757    /// let g = -7.0_f32;
758    ///
759    /// assert!(f.is_sign_positive());
760    /// assert!(!g.is_sign_positive());
761    /// ```
762    #[must_use]
763    #[stable(feature = "rust1", since = "1.0.0")]
764    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
765    #[inline]
766    pub const fn is_sign_positive(self) -> bool {
767        !self.is_sign_negative()
768    }
769
770    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
771    /// negative sign bit and negative infinity.
772    ///
773    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
774    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
775    /// conserved over arithmetic operations, the result of `is_sign_negative` on
776    /// a NaN might produce an unexpected or non-portable result. See the [specification
777    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
778    /// if you need fully portable behavior (will return `false` for all NaNs).
779    ///
780    /// ```
781    /// let f = 7.0f32;
782    /// let g = -7.0f32;
783    ///
784    /// assert!(!f.is_sign_negative());
785    /// assert!(g.is_sign_negative());
786    /// ```
787    #[must_use]
788    #[stable(feature = "rust1", since = "1.0.0")]
789    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
790    #[inline]
791    #[ferrocene::prevalidated]
792    pub const fn is_sign_negative(self) -> bool {
793        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
794        // applies to zeros and NaNs as well.
795        self.to_bits() & 0x8000_0000 != 0
796    }
797
798    /// Returns the least number greater than `self`.
799    ///
800    /// Let `TINY` be the smallest representable positive `f32`. Then,
801    ///  - if `self.is_nan()`, this returns `self`;
802    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
803    ///  - if `self` is `-TINY`, this returns -0.0;
804    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
805    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
806    ///  - otherwise the unique least value greater than `self` is returned.
807    ///
808    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
809    /// is finite `x == x.next_up().next_down()` also holds.
810    ///
811    /// ```rust
812    /// // f32::EPSILON is the difference between 1.0 and the next number up.
813    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
814    /// // But not for most numbers.
815    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
816    /// assert_eq!(16777216f32.next_up(), 16777218.0);
817    /// ```
818    ///
819    /// This operation corresponds to IEEE-754 `nextUp`.
820    ///
821    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
822    /// [`INFINITY`]: Self::INFINITY
823    /// [`MIN`]: Self::MIN
824    /// [`MAX`]: Self::MAX
825    #[inline]
826    #[doc(alias = "nextUp")]
827    #[stable(feature = "float_next_up_down", since = "1.86.0")]
828    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
829    pub const fn next_up(self) -> Self {
830        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
831        // denormals to zero. This is in general unsound and unsupported, but here
832        // we do our best to still produce the correct result on such targets.
833        let bits = self.to_bits();
834        if self.is_nan() || bits == Self::INFINITY.to_bits() {
835            return self;
836        }
837
838        let abs = bits & !Self::SIGN_MASK;
839        let next_bits = if abs == 0 {
840            Self::TINY_BITS
841        } else if bits == abs {
842            bits + 1
843        } else {
844            bits - 1
845        };
846        Self::from_bits(next_bits)
847    }
848
849    /// Returns the greatest number less than `self`.
850    ///
851    /// Let `TINY` be the smallest representable positive `f32`. Then,
852    ///  - if `self.is_nan()`, this returns `self`;
853    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
854    ///  - if `self` is `TINY`, this returns 0.0;
855    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
856    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
857    ///  - otherwise the unique greatest value less than `self` is returned.
858    ///
859    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
860    /// is finite `x == x.next_down().next_up()` also holds.
861    ///
862    /// ```rust
863    /// let x = 1.0f32;
864    /// // Clamp value into range [0, 1).
865    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
866    /// assert!(clamped < 1.0);
867    /// assert_eq!(clamped.next_up(), 1.0);
868    /// ```
869    ///
870    /// This operation corresponds to IEEE-754 `nextDown`.
871    ///
872    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
873    /// [`INFINITY`]: Self::INFINITY
874    /// [`MIN`]: Self::MIN
875    /// [`MAX`]: Self::MAX
876    #[inline]
877    #[doc(alias = "nextDown")]
878    #[stable(feature = "float_next_up_down", since = "1.86.0")]
879    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
880    pub const fn next_down(self) -> Self {
881        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
882        // denormals to zero. This is in general unsound and unsupported, but here
883        // we do our best to still produce the correct result on such targets.
884        let bits = self.to_bits();
885        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
886            return self;
887        }
888
889        let abs = bits & !Self::SIGN_MASK;
890        let next_bits = if abs == 0 {
891            Self::NEG_TINY_BITS
892        } else if bits == abs {
893            bits - 1
894        } else {
895            bits + 1
896        };
897        Self::from_bits(next_bits)
898    }
899
900    /// Takes the reciprocal (inverse) of a number, `1/x`.
901    ///
902    /// ```
903    /// let x = 2.0_f32;
904    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
905    ///
906    /// assert!(abs_difference <= f32::EPSILON);
907    /// ```
908    #[must_use = "this returns the result of the operation, without modifying the original"]
909    #[stable(feature = "rust1", since = "1.0.0")]
910    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
911    #[inline]
912    pub const fn recip(self) -> f32 {
913        1.0 / self
914    }
915
916    /// Converts radians to degrees.
917    ///
918    /// # Unspecified precision
919    ///
920    /// The precision of this function is non-deterministic. This means it varies by platform,
921    /// Rust version, and can even differ within the same execution from one invocation to the next.
922    ///
923    /// # Examples
924    ///
925    /// ```
926    /// let angle = std::f32::consts::PI;
927    ///
928    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
929    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
930    /// assert!(abs_difference <= f32::EPSILON);
931    /// ```
932    #[must_use = "this returns the result of the operation, \
933                  without modifying the original"]
934    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
935    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
936    #[inline]
937    pub const fn to_degrees(self) -> f32 {
938        // Use a literal to avoid double rounding, consts::PI is already rounded,
939        // and dividing would round again.
940        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
941        self * PIS_IN_180
942    }
943
944    /// Converts degrees to radians.
945    ///
946    /// # Unspecified precision
947    ///
948    /// The precision of this function is non-deterministic. This means it varies by platform,
949    /// Rust version, and can even differ within the same execution from one invocation to the next.
950    ///
951    /// # Examples
952    ///
953    /// ```
954    /// let angle = 180.0f32;
955    ///
956    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
957    ///
958    /// assert!(abs_difference <= f32::EPSILON);
959    /// ```
960    #[must_use = "this returns the result of the operation, \
961                  without modifying the original"]
962    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
963    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
964    #[inline]
965    pub const fn to_radians(self) -> f32 {
966        // The division here is correctly rounded with respect to the true value of π/180.
967        // Although π is irrational and already rounded, the double rounding happens
968        // to produce correct result for f32.
969        const RADS_PER_DEG: f32 = consts::PI / 180.0;
970        self * RADS_PER_DEG
971    }
972
973    /// Returns the maximum of the two numbers, ignoring NaN.
974    ///
975    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
976    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
977    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
978    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
979    /// non-deterministically.
980    ///
981    /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all
982    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
983    /// follows the IEEE 754-2008 semantics for `maxNum`.
984    ///
985    /// ```
986    /// let x = 1.0f32;
987    /// let y = 2.0f32;
988    ///
989    /// assert_eq!(x.max(y), y);
990    /// assert_eq!(x.max(f32::NAN), x);
991    /// ```
992    #[must_use = "this returns the result of the comparison, without modifying either input"]
993    #[stable(feature = "rust1", since = "1.0.0")]
994    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
995    #[inline]
996    #[ferrocene::prevalidated]
997    pub const fn max(self, other: f32) -> f32 {
998        intrinsics::maximum_number_nsz_f32(self, other)
999    }
1000
1001    /// Returns the minimum of the two numbers, ignoring NaN.
1002    ///
1003    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1004    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1005    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1006    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1007    /// non-deterministically.
1008    ///
1009    /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all
1010    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1011    /// follows the IEEE 754-2008 semantics for `minNum`.
1012    ///
1013    /// ```
1014    /// let x = 1.0f32;
1015    /// let y = 2.0f32;
1016    ///
1017    /// assert_eq!(x.min(y), x);
1018    /// assert_eq!(x.min(f32::NAN), x);
1019    /// ```
1020    #[must_use = "this returns the result of the comparison, without modifying either input"]
1021    #[stable(feature = "rust1", since = "1.0.0")]
1022    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1023    #[inline]
1024    #[ferrocene::prevalidated]
1025    pub const fn min(self, other: f32) -> f32 {
1026        intrinsics::minimum_number_nsz_f32(self, other)
1027    }
1028
1029    /// Returns the maximum of the two numbers, propagating NaN.
1030    ///
1031    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1032    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1033    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1034    /// non-NaN inputs.
1035    ///
1036    /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN,
1037    /// and which does not reliably order `-0.0` and `+0.0`.
1038    ///
1039    /// This follows the IEEE 754-2019 semantics for `maximum`.
1040    ///
1041    /// ```
1042    /// #![feature(float_minimum_maximum)]
1043    /// let x = 1.0f32;
1044    /// let y = 2.0f32;
1045    ///
1046    /// assert_eq!(x.maximum(y), y);
1047    /// assert!(x.maximum(f32::NAN).is_nan());
1048    /// ```
1049    #[must_use = "this returns the result of the comparison, without modifying either input"]
1050    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1051    #[inline]
1052    pub const fn maximum(self, other: f32) -> f32 {
1053        intrinsics::maximumf32(self, other)
1054    }
1055
1056    /// Returns the minimum of the two numbers, propagating NaN.
1057    ///
1058    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1059    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1060    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1061    /// non-NaN inputs.
1062    ///
1063    /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN,
1064    /// and which does not reliably order `-0.0` and `+0.0`.
1065    ///
1066    /// This follows the IEEE 754-2019 semantics for `minimum`.
1067    ///
1068    /// ```
1069    /// #![feature(float_minimum_maximum)]
1070    /// let x = 1.0f32;
1071    /// let y = 2.0f32;
1072    ///
1073    /// assert_eq!(x.minimum(y), x);
1074    /// assert!(x.minimum(f32::NAN).is_nan());
1075    /// ```
1076    #[must_use = "this returns the result of the comparison, without modifying either input"]
1077    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1078    #[inline]
1079    pub const fn minimum(self, other: f32) -> f32 {
1080        intrinsics::minimumf32(self, other)
1081    }
1082
1083    /// Calculates the midpoint (average) between `self` and `rhs`.
1084    ///
1085    /// This returns NaN when *either* argument is NaN or if a combination of
1086    /// +inf and -inf is provided as arguments.
1087    ///
1088    /// # Examples
1089    ///
1090    /// ```
1091    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1092    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1093    /// ```
1094    #[inline]
1095    #[doc(alias = "average")]
1096    #[stable(feature = "num_midpoint", since = "1.85.0")]
1097    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1098    pub const fn midpoint(self, other: f32) -> f32 {
1099        cfg_select! {
1100            // Allow faster implementation that have known good 64-bit float
1101            // implementations. Falling back to the branchy code on targets that don't
1102            // have 64-bit hardware floats or buggy implementations.
1103            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1104            any(
1105                target_arch = "x86_64",
1106                target_arch = "aarch64",
1107                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1108                all(target_arch = "loongarch64", target_feature = "d"),
1109                all(target_arch = "arm", target_feature = "vfp2"),
1110                target_arch = "wasm32",
1111                target_arch = "wasm64",
1112            ) => {
1113                ((self as f64 + other as f64) / 2.0) as f32
1114            }
1115            _ => {
1116                const HI: f32 = f32::MAX / 2.;
1117
1118                let (a, b) = (self, other);
1119                let abs_a = a.abs();
1120                let abs_b = b.abs();
1121
1122                if abs_a <= HI && abs_b <= HI {
1123                    // Overflow is impossible
1124                    (a + b) / 2.
1125                } else {
1126                    (a / 2.) + (b / 2.)
1127                }
1128            }
1129        }
1130    }
1131
1132    /// Rounds toward zero and converts to any primitive integer type,
1133    /// assuming that the value is finite and fits in that type.
1134    ///
1135    /// ```
1136    /// let value = 4.6_f32;
1137    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1138    /// assert_eq!(rounded, 4);
1139    ///
1140    /// let value = -128.9_f32;
1141    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1142    /// assert_eq!(rounded, i8::MIN);
1143    /// ```
1144    ///
1145    /// # Safety
1146    ///
1147    /// The value must:
1148    ///
1149    /// * Not be `NaN`
1150    /// * Not be infinite
1151    /// * Be representable in the return type `Int`, after truncating off its fractional part
1152    #[must_use = "this returns the result of the operation, \
1153                  without modifying the original"]
1154    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1155    #[inline]
1156    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1157    where
1158        Self: FloatToInt<Int>,
1159    {
1160        // SAFETY: the caller must uphold the safety contract for
1161        // `FloatToInt::to_int_unchecked`.
1162        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1163    }
1164
1165    /// Raw transmutation to `u32`.
1166    ///
1167    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1168    ///
1169    /// See [`from_bits`](Self::from_bits) for some discussion of the
1170    /// portability of this operation (there are almost no issues).
1171    ///
1172    /// Note that this function is distinct from `as` casting, which attempts to
1173    /// preserve the *numeric* value, and not the bitwise value.
1174    ///
1175    /// # Examples
1176    ///
1177    /// ```
1178    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1179    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1180    ///
1181    /// ```
1182    #[must_use = "this returns the result of the operation, \
1183                  without modifying the original"]
1184    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1185    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1186    #[inline]
1187    #[allow(unnecessary_transmutes)]
1188    #[ferrocene::prevalidated]
1189    pub const fn to_bits(self) -> u32 {
1190        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1191        unsafe { mem::transmute(self) }
1192    }
1193
1194    /// Raw transmutation from `u32`.
1195    ///
1196    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1197    /// It turns out this is incredibly portable, for two reasons:
1198    ///
1199    /// * Floats and Ints have the same endianness on all supported platforms.
1200    /// * IEEE 754 very precisely specifies the bit layout of floats.
1201    ///
1202    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1203    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1204    /// (notably x86 and ARM) picked the interpretation that was ultimately
1205    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1206    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1207    ///
1208    /// Rather than trying to preserve signaling-ness cross-platform, this
1209    /// implementation favors preserving the exact bits. This means that
1210    /// any payloads encoded in NaNs will be preserved even if the result of
1211    /// this method is sent over the network from an x86 machine to a MIPS one.
1212    ///
1213    /// If the results of this method are only manipulated by the same
1214    /// architecture that produced them, then there is no portability concern.
1215    ///
1216    /// If the input isn't NaN, then there is no portability concern.
1217    ///
1218    /// If you don't care about signalingness (very likely), then there is no
1219    /// portability concern.
1220    ///
1221    /// Note that this function is distinct from `as` casting, which attempts to
1222    /// preserve the *numeric* value, and not the bitwise value.
1223    ///
1224    /// # Examples
1225    ///
1226    /// ```
1227    /// let v = f32::from_bits(0x41480000);
1228    /// assert_eq!(v, 12.5);
1229    /// ```
1230    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1231    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1232    #[must_use]
1233    #[inline]
1234    #[allow(unnecessary_transmutes)]
1235    #[ferrocene::prevalidated]
1236    pub const fn from_bits(v: u32) -> Self {
1237        // It turns out the safety issues with sNaN were overblown! Hooray!
1238        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1239        unsafe { mem::transmute(v) }
1240    }
1241
1242    /// Returns the memory representation of this floating point number as a byte array in
1243    /// big-endian (network) byte order.
1244    ///
1245    /// See [`from_bits`](Self::from_bits) for some discussion of the
1246    /// portability of this operation (there are almost no issues).
1247    ///
1248    /// # Examples
1249    ///
1250    /// ```
1251    /// let bytes = 12.5f32.to_be_bytes();
1252    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1253    /// ```
1254    #[must_use = "this returns the result of the operation, \
1255                  without modifying the original"]
1256    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1257    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1258    #[inline]
1259    pub const fn to_be_bytes(self) -> [u8; 4] {
1260        self.to_bits().to_be_bytes()
1261    }
1262
1263    /// Returns the memory representation of this floating point number as a byte array in
1264    /// little-endian byte order.
1265    ///
1266    /// See [`from_bits`](Self::from_bits) for some discussion of the
1267    /// portability of this operation (there are almost no issues).
1268    ///
1269    /// # Examples
1270    ///
1271    /// ```
1272    /// let bytes = 12.5f32.to_le_bytes();
1273    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1274    /// ```
1275    #[must_use = "this returns the result of the operation, \
1276                  without modifying the original"]
1277    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1278    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1279    #[inline]
1280    #[ferrocene::prevalidated]
1281    pub const fn to_le_bytes(self) -> [u8; 4] {
1282        self.to_bits().to_le_bytes()
1283    }
1284
1285    /// Returns the memory representation of this floating point number as a byte array in
1286    /// native byte order.
1287    ///
1288    /// As the target platform's native endianness is used, portable code
1289    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1290    ///
1291    /// [`to_be_bytes`]: f32::to_be_bytes
1292    /// [`to_le_bytes`]: f32::to_le_bytes
1293    ///
1294    /// See [`from_bits`](Self::from_bits) for some discussion of the
1295    /// portability of this operation (there are almost no issues).
1296    ///
1297    /// # Examples
1298    ///
1299    /// ```
1300    /// let bytes = 12.5f32.to_ne_bytes();
1301    /// assert_eq!(
1302    ///     bytes,
1303    ///     if cfg!(target_endian = "big") {
1304    ///         [0x41, 0x48, 0x00, 0x00]
1305    ///     } else {
1306    ///         [0x00, 0x00, 0x48, 0x41]
1307    ///     }
1308    /// );
1309    /// ```
1310    #[must_use = "this returns the result of the operation, \
1311                  without modifying the original"]
1312    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1313    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1314    #[inline]
1315    pub const fn to_ne_bytes(self) -> [u8; 4] {
1316        self.to_bits().to_ne_bytes()
1317    }
1318
1319    /// Creates a floating point value from its representation as a byte array in big endian.
1320    ///
1321    /// See [`from_bits`](Self::from_bits) for some discussion of the
1322    /// portability of this operation (there are almost no issues).
1323    ///
1324    /// # Examples
1325    ///
1326    /// ```
1327    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1328    /// assert_eq!(value, 12.5);
1329    /// ```
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    #[must_use]
1333    #[inline]
1334    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1335        Self::from_bits(u32::from_be_bytes(bytes))
1336    }
1337
1338    /// Creates a floating point value from its representation as a byte array in little endian.
1339    ///
1340    /// See [`from_bits`](Self::from_bits) for some discussion of the
1341    /// portability of this operation (there are almost no issues).
1342    ///
1343    /// # Examples
1344    ///
1345    /// ```
1346    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1347    /// assert_eq!(value, 12.5);
1348    /// ```
1349    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1350    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1351    #[must_use]
1352    #[inline]
1353    #[ferrocene::prevalidated]
1354    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1355        Self::from_bits(u32::from_le_bytes(bytes))
1356    }
1357
1358    /// Creates a floating point value from its representation as a byte array in native endian.
1359    ///
1360    /// As the target platform's native endianness is used, portable code
1361    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1362    /// appropriate instead.
1363    ///
1364    /// [`from_be_bytes`]: f32::from_be_bytes
1365    /// [`from_le_bytes`]: f32::from_le_bytes
1366    ///
1367    /// See [`from_bits`](Self::from_bits) for some discussion of the
1368    /// portability of this operation (there are almost no issues).
1369    ///
1370    /// # Examples
1371    ///
1372    /// ```
1373    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1374    ///     [0x41, 0x48, 0x00, 0x00]
1375    /// } else {
1376    ///     [0x00, 0x00, 0x48, 0x41]
1377    /// });
1378    /// assert_eq!(value, 12.5);
1379    /// ```
1380    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1381    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1382    #[must_use]
1383    #[inline]
1384    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1385        Self::from_bits(u32::from_ne_bytes(bytes))
1386    }
1387
1388    /// Returns the ordering between `self` and `other`.
1389    ///
1390    /// Unlike the standard partial comparison between floating point numbers,
1391    /// this comparison always produces an ordering in accordance to
1392    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1393    /// floating point standard. The values are ordered in the following sequence:
1394    ///
1395    /// - negative quiet NaN
1396    /// - negative signaling NaN
1397    /// - negative infinity
1398    /// - negative numbers
1399    /// - negative subnormal numbers
1400    /// - negative zero
1401    /// - positive zero
1402    /// - positive subnormal numbers
1403    /// - positive numbers
1404    /// - positive infinity
1405    /// - positive signaling NaN
1406    /// - positive quiet NaN.
1407    ///
1408    /// The ordering established by this function does not always agree with the
1409    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1410    /// they consider negative and positive zero equal, while `total_cmp`
1411    /// doesn't.
1412    ///
1413    /// The interpretation of the signaling NaN bit follows the definition in
1414    /// the IEEE 754 standard, which may not match the interpretation by some of
1415    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1416    ///
1417    /// # Example
1418    ///
1419    /// ```
1420    /// struct GoodBoy {
1421    ///     name: String,
1422    ///     weight: f32,
1423    /// }
1424    ///
1425    /// let mut bois = vec![
1426    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1427    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1428    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1429    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1430    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1431    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1432    /// ];
1433    ///
1434    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1435    ///
1436    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1437    /// if f32::NAN.is_sign_negative() {
1438    ///     assert!(bois.into_iter().map(|b| b.weight)
1439    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1440    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1441    /// } else {
1442    ///     assert!(bois.into_iter().map(|b| b.weight)
1443    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1444    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1445    /// }
1446    /// ```
1447    #[stable(feature = "total_cmp", since = "1.62.0")]
1448    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1449    #[must_use]
1450    #[inline]
1451    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1452        let mut left = self.to_bits() as i32;
1453        let mut right = other.to_bits() as i32;
1454
1455        // In case of negatives, flip all the bits except the sign
1456        // to achieve a similar layout as two's complement integers
1457        //
1458        // Why does this work? IEEE 754 floats consist of three fields:
1459        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1460        // fields as a whole have the property that their bitwise order is
1461        // equal to the numeric magnitude where the magnitude is defined.
1462        // The magnitude is not normally defined on NaN values, but
1463        // IEEE 754 totalOrder defines the NaN values also to follow the
1464        // bitwise order. This leads to order explained in the doc comment.
1465        // However, the representation of magnitude is the same for negative
1466        // and positive numbers – only the sign bit is different.
1467        // To easily compare the floats as signed integers, we need to
1468        // flip the exponent and mantissa bits in case of negative numbers.
1469        // We effectively convert the numbers to "two's complement" form.
1470        //
1471        // To do the flipping, we construct a mask and XOR against it.
1472        // We branchlessly calculate an "all-ones except for the sign bit"
1473        // mask from negative-signed values: right shifting sign-extends
1474        // the integer, so we "fill" the mask with sign bits, and then
1475        // convert to unsigned to push one more zero bit.
1476        // On positive values, the mask is all zeros, so it's a no-op.
1477        left ^= (((left >> 31) as u32) >> 1) as i32;
1478        right ^= (((right >> 31) as u32) >> 1) as i32;
1479
1480        left.cmp(&right)
1481    }
1482
1483    /// Restrict a value to a certain interval unless it is NaN.
1484    ///
1485    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1486    /// less than `min`. Otherwise this returns `self`.
1487    ///
1488    /// Note that this function returns NaN if the initial value was NaN as
1489    /// well. If the result is zero and among the three inputs `self`, `min`, and `max` there are
1490    /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically.
1491    ///
1492    /// # Panics
1493    ///
1494    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1495    ///
1496    /// # Examples
1497    ///
1498    /// ```
1499    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1500    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1501    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1502    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1503    ///
1504    /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic.
1505    /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0);
1506    /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0);
1507    /// // This is definitely a negative zero.
1508    /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative());
1509    /// ```
1510    #[must_use = "method returns a new number and does not mutate the original value"]
1511    #[stable(feature = "clamp", since = "1.50.0")]
1512    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1513    #[inline]
1514    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1515        const_assert!(
1516            min <= max,
1517            "min > max, or either was NaN",
1518            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1519            min: f32,
1520            max: f32,
1521        );
1522
1523        if self < min {
1524            self = min;
1525        }
1526        if self > max {
1527            self = max;
1528        }
1529        self
1530    }
1531
1532    /// Clamps this number to a symmetric range centered around zero.
1533    ///
1534    /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
1535    ///
1536    /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
1537    /// explicit about the intent.
1538    ///
1539    /// # Panics
1540    ///
1541    /// Panics if `limit` is negative or NaN, as this indicates a logic error.
1542    ///
1543    /// # Examples
1544    ///
1545    /// ```
1546    /// #![feature(clamp_magnitude)]
1547    /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0);
1548    /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0);
1549    /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0);
1550    /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0);
1551    /// ```
1552    #[must_use = "this returns the clamped value and does not modify the original"]
1553    #[unstable(feature = "clamp_magnitude", issue = "148519")]
1554    #[inline]
1555    pub fn clamp_magnitude(self, limit: f32) -> f32 {
1556        assert!(limit >= 0.0, "limit must be non-negative");
1557        let limit = limit.abs(); // Canonicalises -0.0 to 0.0
1558        self.clamp(-limit, limit)
1559    }
1560
1561    /// Computes the absolute value of `self`.
1562    ///
1563    /// This function always returns the precise result.
1564    ///
1565    /// # Examples
1566    ///
1567    /// ```
1568    /// let x = 3.5_f32;
1569    /// let y = -3.5_f32;
1570    ///
1571    /// assert_eq!(x.abs(), x);
1572    /// assert_eq!(y.abs(), -y);
1573    ///
1574    /// assert!(f32::NAN.abs().is_nan());
1575    /// ```
1576    #[must_use = "method returns a new number and does not mutate the original value"]
1577    #[stable(feature = "rust1", since = "1.0.0")]
1578    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1579    #[inline]
1580    #[ferrocene::prevalidated]
1581    pub const fn abs(self) -> f32 {
1582        intrinsics::fabsf32(self)
1583    }
1584
1585    /// Returns a number that represents the sign of `self`.
1586    ///
1587    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1588    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1589    /// - NaN if the number is NaN
1590    ///
1591    /// # Examples
1592    ///
1593    /// ```
1594    /// let f = 3.5_f32;
1595    ///
1596    /// assert_eq!(f.signum(), 1.0);
1597    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1598    ///
1599    /// assert!(f32::NAN.signum().is_nan());
1600    /// ```
1601    #[must_use = "method returns a new number and does not mutate the original value"]
1602    #[stable(feature = "rust1", since = "1.0.0")]
1603    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1604    #[inline]
1605    #[ferrocene::prevalidated]
1606    pub const fn signum(self) -> f32 {
1607        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1608    }
1609
1610    /// Returns a number composed of the magnitude of `self` and the sign of
1611    /// `sign`.
1612    ///
1613    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1614    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1615    /// returned.
1616    ///
1617    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1618    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1619    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1620    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1621    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1622    /// info.
1623    ///
1624    /// # Examples
1625    ///
1626    /// ```
1627    /// let f = 3.5_f32;
1628    ///
1629    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1630    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1631    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1632    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1633    ///
1634    /// assert!(f32::NAN.copysign(1.0).is_nan());
1635    /// ```
1636    #[must_use = "method returns a new number and does not mutate the original value"]
1637    #[inline]
1638    #[stable(feature = "copysign", since = "1.35.0")]
1639    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1640    #[ferrocene::prevalidated]
1641    pub const fn copysign(self, sign: f32) -> f32 {
1642        intrinsics::copysignf32(self, sign)
1643    }
1644
1645    /// Float addition that allows optimizations based on algebraic rules.
1646    ///
1647    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1648    #[must_use = "method returns a new number and does not mutate the original value"]
1649    #[unstable(feature = "float_algebraic", issue = "136469")]
1650    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1651    #[inline]
1652    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1653        intrinsics::fadd_algebraic(self, rhs)
1654    }
1655
1656    /// Float subtraction that allows optimizations based on algebraic rules.
1657    ///
1658    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1659    #[must_use = "method returns a new number and does not mutate the original value"]
1660    #[unstable(feature = "float_algebraic", issue = "136469")]
1661    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1662    #[inline]
1663    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1664        intrinsics::fsub_algebraic(self, rhs)
1665    }
1666
1667    /// Float multiplication that allows optimizations based on algebraic rules.
1668    ///
1669    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1670    #[must_use = "method returns a new number and does not mutate the original value"]
1671    #[unstable(feature = "float_algebraic", issue = "136469")]
1672    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1673    #[inline]
1674    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1675        intrinsics::fmul_algebraic(self, rhs)
1676    }
1677
1678    /// Float division that allows optimizations based on algebraic rules.
1679    ///
1680    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1681    #[must_use = "method returns a new number and does not mutate the original value"]
1682    #[unstable(feature = "float_algebraic", issue = "136469")]
1683    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1684    #[inline]
1685    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1686        intrinsics::fdiv_algebraic(self, rhs)
1687    }
1688
1689    /// Float remainder that allows optimizations based on algebraic rules.
1690    ///
1691    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1692    #[must_use = "method returns a new number and does not mutate the original value"]
1693    #[unstable(feature = "float_algebraic", issue = "136469")]
1694    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1695    #[inline]
1696    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1697        intrinsics::frem_algebraic(self, rhs)
1698    }
1699}
1700
1701/// Experimental implementations of floating point functions in `core`.
1702///
1703/// _The standalone functions in this module are for testing only.
1704/// They will be stabilized as inherent methods._
1705#[unstable(feature = "core_float_math", issue = "137578")]
1706pub mod math {
1707    use crate::intrinsics;
1708    use crate::num::imp::libm;
1709
1710    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1711    ///
1712    /// # Examples
1713    ///
1714    /// ```
1715    /// #![feature(core_float_math)]
1716    ///
1717    /// use core::f32;
1718    ///
1719    /// let f = 3.7_f32;
1720    /// let g = 3.0_f32;
1721    /// let h = -3.7_f32;
1722    ///
1723    /// assert_eq!(f32::math::floor(f), 3.0);
1724    /// assert_eq!(f32::math::floor(g), 3.0);
1725    /// assert_eq!(f32::math::floor(h), -4.0);
1726    /// ```
1727    ///
1728    /// _This standalone function is for testing only.
1729    /// It will be stabilized as an inherent method._
1730    ///
1731    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
1732    #[inline]
1733    #[unstable(feature = "core_float_math", issue = "137578")]
1734    #[must_use = "method returns a new number and does not mutate the original value"]
1735    pub const fn floor(x: f32) -> f32 {
1736        intrinsics::floorf32(x)
1737    }
1738
1739    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1740    ///
1741    /// # Examples
1742    ///
1743    /// ```
1744    /// #![feature(core_float_math)]
1745    ///
1746    /// use core::f32;
1747    ///
1748    /// let f = 3.01_f32;
1749    /// let g = 4.0_f32;
1750    ///
1751    /// assert_eq!(f32::math::ceil(f), 4.0);
1752    /// assert_eq!(f32::math::ceil(g), 4.0);
1753    /// ```
1754    ///
1755    /// _This standalone function is for testing only.
1756    /// It will be stabilized as an inherent method._
1757    ///
1758    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1759    #[inline]
1760    #[doc(alias = "ceiling")]
1761    #[must_use = "method returns a new number and does not mutate the original value"]
1762    #[unstable(feature = "core_float_math", issue = "137578")]
1763    pub const fn ceil(x: f32) -> f32 {
1764        intrinsics::ceilf32(x)
1765    }
1766
1767    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1768    ///
1769    /// # Examples
1770    ///
1771    /// ```
1772    /// #![feature(core_float_math)]
1773    ///
1774    /// use core::f32;
1775    ///
1776    /// let f = 3.3_f32;
1777    /// let g = -3.3_f32;
1778    /// let h = -3.7_f32;
1779    /// let i = 3.5_f32;
1780    /// let j = 4.5_f32;
1781    ///
1782    /// assert_eq!(f32::math::round(f), 3.0);
1783    /// assert_eq!(f32::math::round(g), -3.0);
1784    /// assert_eq!(f32::math::round(h), -4.0);
1785    /// assert_eq!(f32::math::round(i), 4.0);
1786    /// assert_eq!(f32::math::round(j), 5.0);
1787    /// ```
1788    ///
1789    /// _This standalone function is for testing only.
1790    /// It will be stabilized as an inherent method._
1791    ///
1792    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1793    #[inline]
1794    #[unstable(feature = "core_float_math", issue = "137578")]
1795    #[must_use = "method returns a new number and does not mutate the original value"]
1796    pub const fn round(x: f32) -> f32 {
1797        intrinsics::roundf32(x)
1798    }
1799
1800    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1801    /// details.
1802    ///
1803    /// # Examples
1804    ///
1805    /// ```
1806    /// #![feature(core_float_math)]
1807    ///
1808    /// use core::f32;
1809    ///
1810    /// let f = 3.3_f32;
1811    /// let g = -3.3_f32;
1812    /// let h = 3.5_f32;
1813    /// let i = 4.5_f32;
1814    ///
1815    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1816    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1817    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1818    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1819    /// ```
1820    ///
1821    /// _This standalone function is for testing only.
1822    /// It will be stabilized as an inherent method._
1823    ///
1824    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1825    #[inline]
1826    #[unstable(feature = "core_float_math", issue = "137578")]
1827    #[must_use = "method returns a new number and does not mutate the original value"]
1828    pub const fn round_ties_even(x: f32) -> f32 {
1829        intrinsics::round_ties_even_f32(x)
1830    }
1831
1832    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1833    ///
1834    /// # Examples
1835    ///
1836    /// ```
1837    /// #![feature(core_float_math)]
1838    ///
1839    /// use core::f32;
1840    ///
1841    /// let f = 3.7_f32;
1842    /// let g = 3.0_f32;
1843    /// let h = -3.7_f32;
1844    ///
1845    /// assert_eq!(f32::math::trunc(f), 3.0);
1846    /// assert_eq!(f32::math::trunc(g), 3.0);
1847    /// assert_eq!(f32::math::trunc(h), -3.0);
1848    /// ```
1849    ///
1850    /// _This standalone function is for testing only.
1851    /// It will be stabilized as an inherent method._
1852    ///
1853    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1854    #[inline]
1855    #[doc(alias = "truncate")]
1856    #[must_use = "method returns a new number and does not mutate the original value"]
1857    #[unstable(feature = "core_float_math", issue = "137578")]
1858    pub const fn trunc(x: f32) -> f32 {
1859        intrinsics::truncf32(x)
1860    }
1861
1862    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1863    ///
1864    /// # Examples
1865    ///
1866    /// ```
1867    /// #![feature(core_float_math)]
1868    ///
1869    /// use core::f32;
1870    ///
1871    /// let x = 3.6_f32;
1872    /// let y = -3.6_f32;
1873    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1874    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1875    ///
1876    /// assert!(abs_difference_x <= f32::EPSILON);
1877    /// assert!(abs_difference_y <= f32::EPSILON);
1878    /// ```
1879    ///
1880    /// _This standalone function is for testing only.
1881    /// It will be stabilized as an inherent method._
1882    ///
1883    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1884    #[inline]
1885    #[unstable(feature = "core_float_math", issue = "137578")]
1886    #[must_use = "method returns a new number and does not mutate the original value"]
1887    pub const fn fract(x: f32) -> f32 {
1888        x - trunc(x)
1889    }
1890
1891    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1892    ///
1893    /// # Examples
1894    ///
1895    /// ```
1896    /// # #![allow(unused_features)]
1897    /// #![feature(core_float_math)]
1898    ///
1899    /// # // FIXME(#140515): mingw has an incorrect fma
1900    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1901    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1902    /// use core::f32;
1903    ///
1904    /// let m = 10.0_f32;
1905    /// let x = 4.0_f32;
1906    /// let b = 60.0_f32;
1907    ///
1908    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1909    /// assert_eq!(m * x + b, 100.0);
1910    ///
1911    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1912    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1913    /// let minus_one = -1.0_f32;
1914    ///
1915    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1916    /// assert_eq!(
1917    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1918    ///     -f32::EPSILON * f32::EPSILON
1919    /// );
1920    /// // Different rounding with the non-fused multiply and add.
1921    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1922    /// # }
1923    /// ```
1924    ///
1925    /// _This standalone function is for testing only.
1926    /// It will be stabilized as an inherent method._
1927    ///
1928    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1929    #[inline]
1930    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1931    #[must_use = "method returns a new number and does not mutate the original value"]
1932    #[unstable(feature = "core_float_math", issue = "137578")]
1933    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1934        intrinsics::fmaf32(x, y, z)
1935    }
1936
1937    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1938    ///
1939    /// # Examples
1940    ///
1941    /// ```
1942    /// #![feature(core_float_math)]
1943    ///
1944    /// use core::f32;
1945    ///
1946    /// let a: f32 = 7.0;
1947    /// let b = 4.0;
1948    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
1949    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
1950    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
1951    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
1952    /// ```
1953    ///
1954    /// _This standalone function is for testing only.
1955    /// It will be stabilized as an inherent method._
1956    ///
1957    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
1958    #[inline]
1959    #[unstable(feature = "core_float_math", issue = "137578")]
1960    #[must_use = "method returns a new number and does not mutate the original value"]
1961    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
1962        let q = trunc(x / rhs);
1963        if x % rhs < 0.0 {
1964            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
1965        }
1966        q
1967    }
1968
1969    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
1970    ///
1971    /// # Examples
1972    ///
1973    /// ```
1974    /// #![feature(core_float_math)]
1975    ///
1976    /// use core::f32;
1977    ///
1978    /// let a: f32 = 7.0;
1979    /// let b = 4.0;
1980    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
1981    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
1982    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
1983    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
1984    /// // limitation due to round-off error
1985    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
1986    /// ```
1987    ///
1988    /// _This standalone function is for testing only.
1989    /// It will be stabilized as an inherent method._
1990    ///
1991    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
1992    #[inline]
1993    #[doc(alias = "modulo", alias = "mod")]
1994    #[unstable(feature = "core_float_math", issue = "137578")]
1995    #[must_use = "method returns a new number and does not mutate the original value"]
1996    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
1997        let r = x % rhs;
1998        if r < 0.0 { r + rhs.abs() } else { r }
1999    }
2000
2001    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
2002    ///
2003    /// # Examples
2004    ///
2005    /// ```
2006    /// #![feature(core_float_math)]
2007    ///
2008    /// use core::f32;
2009    ///
2010    /// let x = 2.0_f32;
2011    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
2012    /// assert!(abs_difference <= 1e-5);
2013    ///
2014    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
2015    /// ```
2016    ///
2017    /// _This standalone function is for testing only.
2018    /// It will be stabilized as an inherent method._
2019    ///
2020    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
2021    #[inline]
2022    #[must_use = "method returns a new number and does not mutate the original value"]
2023    #[unstable(feature = "core_float_math", issue = "137578")]
2024    pub fn powi(x: f32, n: i32) -> f32 {
2025        intrinsics::powif32(x, n)
2026    }
2027
2028    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
2029    ///
2030    /// # Examples
2031    ///
2032    /// ```
2033    /// #![feature(core_float_math)]
2034    ///
2035    /// use core::f32;
2036    ///
2037    /// let positive = 4.0_f32;
2038    /// let negative = -4.0_f32;
2039    /// let negative_zero = -0.0_f32;
2040    ///
2041    /// assert_eq!(f32::math::sqrt(positive), 2.0);
2042    /// assert!(f32::math::sqrt(negative).is_nan());
2043    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
2044    /// ```
2045    ///
2046    /// _This standalone function is for testing only.
2047    /// It will be stabilized as an inherent method._
2048    ///
2049    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
2050    #[inline]
2051    #[doc(alias = "squareRoot")]
2052    #[unstable(feature = "core_float_math", issue = "137578")]
2053    #[must_use = "method returns a new number and does not mutate the original value"]
2054    pub fn sqrt(x: f32) -> f32 {
2055        intrinsics::sqrtf32(x)
2056    }
2057
2058    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
2059    ///
2060    /// # Examples
2061    ///
2062    /// ```
2063    /// #![feature(core_float_math)]
2064    ///
2065    /// use core::f32;
2066    ///
2067    /// let x = 3.0f32;
2068    /// let y = -3.0f32;
2069    ///
2070    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
2071    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
2072    ///
2073    /// assert!(abs_difference_x <= 1e-6);
2074    /// assert!(abs_difference_y <= 1e-6);
2075    /// ```
2076    ///
2077    /// _This standalone function is for testing only.
2078    /// It will be stabilized as an inherent method._
2079    ///
2080    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
2081    #[inline]
2082    #[stable(feature = "rust1", since = "1.0.0")]
2083    #[deprecated(
2084        since = "1.10.0",
2085        note = "you probably meant `(self - other).abs()`: \
2086            this operation is `(self - other).max(0.0)` \
2087            except that `abs_sub` also propagates NaNs (also \
2088            known as `fdimf` in C). If you truly need the positive \
2089            difference, consider using that expression or the C function \
2090            `fdimf`, depending on how you wish to handle NaN (please consider \
2091            filing an issue describing your use-case too)."
2092    )]
2093    #[must_use = "method returns a new number and does not mutate the original value"]
2094    pub fn abs_sub(x: f32, other: f32) -> f32 {
2095        libm::fdimf(x, other)
2096    }
2097
2098    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
2099    ///
2100    /// # Unspecified precision
2101    ///
2102    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
2103    /// can even differ within the same execution from one invocation to the next.
2104    /// This function currently corresponds to the `cbrtf` from libc on Unix
2105    /// and Windows. Note that this might change in the future.
2106    ///
2107    /// # Examples
2108    ///
2109    /// ```
2110    /// #![feature(core_float_math)]
2111    ///
2112    /// use core::f32;
2113    ///
2114    /// let x = 8.0f32;
2115    ///
2116    /// // x^(1/3) - 2 == 0
2117    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
2118    ///
2119    /// assert!(abs_difference <= 1e-6);
2120    /// ```
2121    ///
2122    /// _This standalone function is for testing only.
2123    /// It will be stabilized as an inherent method._
2124    ///
2125    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
2126    #[inline]
2127    #[must_use = "method returns a new number and does not mutate the original value"]
2128    #[unstable(feature = "core_float_math", issue = "137578")]
2129    pub fn cbrt(x: f32) -> f32 {
2130        libm::cbrtf(x)
2131    }
2132}