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core/num/
f32.rs

1//! Constants for the `f32` single-precision floating point type.
2//!
3//! *[See also the `f32` primitive type][f32].*
4//!
5//! Mathematically significant numbers are provided in the `consts` sub-module.
6//!
7//! For the constants defined directly in this module
8//! (as distinct from those defined in the `consts` sub-module),
9//! new code should instead use the associated constants
10//! defined directly on the `f32` type.
11
12#![stable(feature = "rust1", since = "1.0.0")]
13
14use crate::convert::FloatToInt;
15use crate::num::FpCategory;
16use crate::panic::const_assert;
17use crate::{cfg_select, intrinsics, mem};
18
19/// The radix or base of the internal representation of `f32`.
20/// Use [`f32::RADIX`] instead.
21///
22/// # Examples
23///
24/// ```rust
25/// // deprecated way
26/// # #[allow(deprecated, deprecated_in_future)]
27/// let r = std::f32::RADIX;
28///
29/// // intended way
30/// let r = f32::RADIX;
31/// ```
32#[stable(feature = "rust1", since = "1.0.0")]
33#[deprecated(since = "TBD", note = "replaced by the `RADIX` associated constant on `f32`")]
34#[rustc_diagnostic_item = "f32_legacy_const_radix"]
35pub const RADIX: u32 = f32::RADIX;
36
37/// Number of significant digits in base 2.
38/// Use [`f32::MANTISSA_DIGITS`] instead.
39///
40/// # Examples
41///
42/// ```rust
43/// // deprecated way
44/// # #[allow(deprecated, deprecated_in_future)]
45/// let d = std::f32::MANTISSA_DIGITS;
46///
47/// // intended way
48/// let d = f32::MANTISSA_DIGITS;
49/// ```
50#[stable(feature = "rust1", since = "1.0.0")]
51#[deprecated(
52    since = "TBD",
53    note = "replaced by the `MANTISSA_DIGITS` associated constant on `f32`"
54)]
55#[rustc_diagnostic_item = "f32_legacy_const_mantissa_dig"]
56pub const MANTISSA_DIGITS: u32 = f32::MANTISSA_DIGITS;
57
58/// Approximate number of significant digits in base 10.
59/// Use [`f32::DIGITS`] instead.
60///
61/// # Examples
62///
63/// ```rust
64/// // deprecated way
65/// # #[allow(deprecated, deprecated_in_future)]
66/// let d = std::f32::DIGITS;
67///
68/// // intended way
69/// let d = f32::DIGITS;
70/// ```
71#[stable(feature = "rust1", since = "1.0.0")]
72#[deprecated(since = "TBD", note = "replaced by the `DIGITS` associated constant on `f32`")]
73#[rustc_diagnostic_item = "f32_legacy_const_digits"]
74pub const DIGITS: u32 = f32::DIGITS;
75
76/// [Machine epsilon] value for `f32`.
77/// Use [`f32::EPSILON`] instead.
78///
79/// This is the difference between `1.0` and the next larger representable number.
80///
81/// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
82///
83/// # Examples
84///
85/// ```rust
86/// // deprecated way
87/// # #[allow(deprecated, deprecated_in_future)]
88/// let e = std::f32::EPSILON;
89///
90/// // intended way
91/// let e = f32::EPSILON;
92/// ```
93#[stable(feature = "rust1", since = "1.0.0")]
94#[deprecated(since = "TBD", note = "replaced by the `EPSILON` associated constant on `f32`")]
95#[rustc_diagnostic_item = "f32_legacy_const_epsilon"]
96pub const EPSILON: f32 = f32::EPSILON;
97
98/// Smallest finite `f32` value.
99/// Use [`f32::MIN`] instead.
100///
101/// # Examples
102///
103/// ```rust
104/// // deprecated way
105/// # #[allow(deprecated, deprecated_in_future)]
106/// let min = std::f32::MIN;
107///
108/// // intended way
109/// let min = f32::MIN;
110/// ```
111#[stable(feature = "rust1", since = "1.0.0")]
112#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on `f32`")]
113#[rustc_diagnostic_item = "f32_legacy_const_min"]
114pub const MIN: f32 = f32::MIN;
115
116/// Smallest positive normal `f32` value.
117/// Use [`f32::MIN_POSITIVE`] instead.
118///
119/// # Examples
120///
121/// ```rust
122/// // deprecated way
123/// # #[allow(deprecated, deprecated_in_future)]
124/// let min = std::f32::MIN_POSITIVE;
125///
126/// // intended way
127/// let min = f32::MIN_POSITIVE;
128/// ```
129#[stable(feature = "rust1", since = "1.0.0")]
130#[deprecated(since = "TBD", note = "replaced by the `MIN_POSITIVE` associated constant on `f32`")]
131#[rustc_diagnostic_item = "f32_legacy_const_min_positive"]
132pub const MIN_POSITIVE: f32 = f32::MIN_POSITIVE;
133
134/// Largest finite `f32` value.
135/// Use [`f32::MAX`] instead.
136///
137/// # Examples
138///
139/// ```rust
140/// // deprecated way
141/// # #[allow(deprecated, deprecated_in_future)]
142/// let max = std::f32::MAX;
143///
144/// // intended way
145/// let max = f32::MAX;
146/// ```
147#[stable(feature = "rust1", since = "1.0.0")]
148#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on `f32`")]
149#[rustc_diagnostic_item = "f32_legacy_const_max"]
150pub const MAX: f32 = f32::MAX;
151
152/// One greater than the minimum possible normal power of 2 exponent.
153/// Use [`f32::MIN_EXP`] instead.
154///
155/// # Examples
156///
157/// ```rust
158/// // deprecated way
159/// # #[allow(deprecated, deprecated_in_future)]
160/// let min = std::f32::MIN_EXP;
161///
162/// // intended way
163/// let min = f32::MIN_EXP;
164/// ```
165#[stable(feature = "rust1", since = "1.0.0")]
166#[deprecated(since = "TBD", note = "replaced by the `MIN_EXP` associated constant on `f32`")]
167#[rustc_diagnostic_item = "f32_legacy_const_min_exp"]
168pub const MIN_EXP: i32 = f32::MIN_EXP;
169
170/// Maximum possible power of 2 exponent.
171/// Use [`f32::MAX_EXP`] instead.
172///
173/// # Examples
174///
175/// ```rust
176/// // deprecated way
177/// # #[allow(deprecated, deprecated_in_future)]
178/// let max = std::f32::MAX_EXP;
179///
180/// // intended way
181/// let max = f32::MAX_EXP;
182/// ```
183#[stable(feature = "rust1", since = "1.0.0")]
184#[deprecated(since = "TBD", note = "replaced by the `MAX_EXP` associated constant on `f32`")]
185#[rustc_diagnostic_item = "f32_legacy_const_max_exp"]
186pub const MAX_EXP: i32 = f32::MAX_EXP;
187
188/// Minimum possible normal power of 10 exponent.
189/// Use [`f32::MIN_10_EXP`] instead.
190///
191/// # Examples
192///
193/// ```rust
194/// // deprecated way
195/// # #[allow(deprecated, deprecated_in_future)]
196/// let min = std::f32::MIN_10_EXP;
197///
198/// // intended way
199/// let min = f32::MIN_10_EXP;
200/// ```
201#[stable(feature = "rust1", since = "1.0.0")]
202#[deprecated(since = "TBD", note = "replaced by the `MIN_10_EXP` associated constant on `f32`")]
203#[rustc_diagnostic_item = "f32_legacy_const_min_10_exp"]
204pub const MIN_10_EXP: i32 = f32::MIN_10_EXP;
205
206/// Maximum possible power of 10 exponent.
207/// Use [`f32::MAX_10_EXP`] instead.
208///
209/// # Examples
210///
211/// ```rust
212/// // deprecated way
213/// # #[allow(deprecated, deprecated_in_future)]
214/// let max = std::f32::MAX_10_EXP;
215///
216/// // intended way
217/// let max = f32::MAX_10_EXP;
218/// ```
219#[stable(feature = "rust1", since = "1.0.0")]
220#[deprecated(since = "TBD", note = "replaced by the `MAX_10_EXP` associated constant on `f32`")]
221#[rustc_diagnostic_item = "f32_legacy_const_max_10_exp"]
222pub const MAX_10_EXP: i32 = f32::MAX_10_EXP;
223
224/// Not a Number (NaN).
225/// Use [`f32::NAN`] instead.
226///
227/// # Examples
228///
229/// ```rust
230/// // deprecated way
231/// # #[allow(deprecated, deprecated_in_future)]
232/// let nan = std::f32::NAN;
233///
234/// // intended way
235/// let nan = f32::NAN;
236/// ```
237#[stable(feature = "rust1", since = "1.0.0")]
238#[deprecated(since = "TBD", note = "replaced by the `NAN` associated constant on `f32`")]
239#[rustc_diagnostic_item = "f32_legacy_const_nan"]
240pub const NAN: f32 = f32::NAN;
241
242/// Infinity (∞).
243/// Use [`f32::INFINITY`] instead.
244///
245/// # Examples
246///
247/// ```rust
248/// // deprecated way
249/// # #[allow(deprecated, deprecated_in_future)]
250/// let inf = std::f32::INFINITY;
251///
252/// // intended way
253/// let inf = f32::INFINITY;
254/// ```
255#[stable(feature = "rust1", since = "1.0.0")]
256#[deprecated(since = "TBD", note = "replaced by the `INFINITY` associated constant on `f32`")]
257#[rustc_diagnostic_item = "f32_legacy_const_infinity"]
258pub const INFINITY: f32 = f32::INFINITY;
259
260/// Negative infinity (−∞).
261/// Use [`f32::NEG_INFINITY`] instead.
262///
263/// # Examples
264///
265/// ```rust
266/// // deprecated way
267/// # #[allow(deprecated, deprecated_in_future)]
268/// let ninf = std::f32::NEG_INFINITY;
269///
270/// // intended way
271/// let ninf = f32::NEG_INFINITY;
272/// ```
273#[stable(feature = "rust1", since = "1.0.0")]
274#[deprecated(since = "TBD", note = "replaced by the `NEG_INFINITY` associated constant on `f32`")]
275#[rustc_diagnostic_item = "f32_legacy_const_neg_infinity"]
276pub const NEG_INFINITY: f32 = f32::NEG_INFINITY;
277
278/// Basic mathematical constants.
279#[stable(feature = "rust1", since = "1.0.0")]
280#[rustc_diagnostic_item = "f32_consts_mod"]
281pub mod consts {
282    // FIXME: replace with mathematical constants from cmath.
283
284    /// Archimedes' constant (π)
285    #[stable(feature = "rust1", since = "1.0.0")]
286    pub const PI: f32 = 3.14159265358979323846264338327950288_f32;
287
288    /// The full circle constant (τ)
289    ///
290    /// Equal to 2π.
291    #[stable(feature = "tau_constant", since = "1.47.0")]
292    pub const TAU: f32 = 6.28318530717958647692528676655900577_f32;
293
294    /// The golden ratio (φ)
295    #[doc(alias = "phi")]
296    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
297    pub const GOLDEN_RATIO: f32 = 1.618033988749894848204586834365638118_f32;
298
299    /// The Euler-Mascheroni constant (γ)
300    #[stable(feature = "euler_gamma_golden_ratio", since = "1.94.0")]
301    pub const EULER_GAMMA: f32 = 0.577215664901532860606512090082402431_f32;
302
303    /// π/2
304    #[stable(feature = "rust1", since = "1.0.0")]
305    pub const FRAC_PI_2: f32 = 1.57079632679489661923132169163975144_f32;
306
307    /// π/3
308    #[stable(feature = "rust1", since = "1.0.0")]
309    pub const FRAC_PI_3: f32 = 1.04719755119659774615421446109316763_f32;
310
311    /// π/4
312    #[stable(feature = "rust1", since = "1.0.0")]
313    pub const FRAC_PI_4: f32 = 0.785398163397448309615660845819875721_f32;
314
315    /// π/6
316    #[stable(feature = "rust1", since = "1.0.0")]
317    pub const FRAC_PI_6: f32 = 0.52359877559829887307710723054658381_f32;
318
319    /// π/8
320    #[stable(feature = "rust1", since = "1.0.0")]
321    pub const FRAC_PI_8: f32 = 0.39269908169872415480783042290993786_f32;
322
323    /// 1/π
324    #[stable(feature = "rust1", since = "1.0.0")]
325    pub const FRAC_1_PI: f32 = 0.318309886183790671537767526745028724_f32;
326
327    /// 1/sqrt(π)
328    #[unstable(feature = "more_float_constants", issue = "146939")]
329    pub const FRAC_1_SQRT_PI: f32 = 0.564189583547756286948079451560772586_f32;
330
331    /// 1/sqrt(2π)
332    #[doc(alias = "FRAC_1_SQRT_TAU")]
333    #[unstable(feature = "more_float_constants", issue = "146939")]
334    pub const FRAC_1_SQRT_2PI: f32 = 0.398942280401432677939946059934381868_f32;
335
336    /// 2/π
337    #[stable(feature = "rust1", since = "1.0.0")]
338    pub const FRAC_2_PI: f32 = 0.636619772367581343075535053490057448_f32;
339
340    /// 2/sqrt(π)
341    #[stable(feature = "rust1", since = "1.0.0")]
342    pub const FRAC_2_SQRT_PI: f32 = 1.12837916709551257389615890312154517_f32;
343
344    /// sqrt(2)
345    #[stable(feature = "rust1", since = "1.0.0")]
346    pub const SQRT_2: f32 = 1.41421356237309504880168872420969808_f32;
347
348    /// 1/sqrt(2)
349    #[stable(feature = "rust1", since = "1.0.0")]
350    pub const FRAC_1_SQRT_2: f32 = 0.707106781186547524400844362104849039_f32;
351
352    /// sqrt(3)
353    #[unstable(feature = "more_float_constants", issue = "146939")]
354    pub const SQRT_3: f32 = 1.732050807568877293527446341505872367_f32;
355
356    /// 1/sqrt(3)
357    #[unstable(feature = "more_float_constants", issue = "146939")]
358    pub const FRAC_1_SQRT_3: f32 = 0.577350269189625764509148780501957456_f32;
359
360    /// sqrt(5)
361    #[unstable(feature = "more_float_constants", issue = "146939")]
362    pub const SQRT_5: f32 = 2.23606797749978969640917366873127623_f32;
363
364    /// 1/sqrt(5)
365    #[unstable(feature = "more_float_constants", issue = "146939")]
366    pub const FRAC_1_SQRT_5: f32 = 0.44721359549995793928183473374625524_f32;
367
368    /// Euler's number (e)
369    #[stable(feature = "rust1", since = "1.0.0")]
370    pub const E: f32 = 2.71828182845904523536028747135266250_f32;
371
372    /// log<sub>2</sub>(e)
373    #[stable(feature = "rust1", since = "1.0.0")]
374    pub const LOG2_E: f32 = 1.44269504088896340735992468100189214_f32;
375
376    /// log<sub>2</sub>(10)
377    #[stable(feature = "extra_log_consts", since = "1.43.0")]
378    pub const LOG2_10: f32 = 3.32192809488736234787031942948939018_f32;
379
380    /// log<sub>10</sub>(e)
381    #[stable(feature = "rust1", since = "1.0.0")]
382    pub const LOG10_E: f32 = 0.434294481903251827651128918916605082_f32;
383
384    /// log<sub>10</sub>(2)
385    #[stable(feature = "extra_log_consts", since = "1.43.0")]
386    pub const LOG10_2: f32 = 0.301029995663981195213738894724493027_f32;
387
388    /// ln(2)
389    #[stable(feature = "rust1", since = "1.0.0")]
390    pub const LN_2: f32 = 0.693147180559945309417232121458176568_f32;
391
392    /// ln(10)
393    #[stable(feature = "rust1", since = "1.0.0")]
394    pub const LN_10: f32 = 2.30258509299404568401799145468436421_f32;
395}
396
397#[doc(test(attr(allow(unused_features))))]
398impl f32 {
399    /// The radix or base of the internal representation of `f32`.
400    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
401    pub const RADIX: u32 = 2;
402
403    /// The size of this float type in bits.
404    #[unstable(feature = "float_bits_const", issue = "151073")]
405    pub const BITS: u32 = 32;
406
407    /// Number of significant digits in base 2.
408    ///
409    /// Note that the size of the mantissa in the bitwise representation is one
410    /// smaller than this since the leading 1 is not stored explicitly.
411    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
412    pub const MANTISSA_DIGITS: u32 = 24;
413
414    /// Approximate number of significant digits in base 10.
415    ///
416    /// This is the maximum <i>x</i> such that any decimal number with <i>x</i>
417    /// significant digits can be converted to `f32` and back without loss.
418    ///
419    /// Equal to floor(log<sub>10</sub>&nbsp;2<sup>[`MANTISSA_DIGITS`]&nbsp;&minus;&nbsp;1</sup>).
420    ///
421    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
422    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
423    pub const DIGITS: u32 = 6;
424
425    /// [Machine epsilon] value for `f32`.
426    ///
427    /// This is the difference between `1.0` and the next larger representable number.
428    ///
429    /// Equal to 2<sup>1&nbsp;&minus;&nbsp;[`MANTISSA_DIGITS`]</sup>.
430    ///
431    /// [Machine epsilon]: https://en.wikipedia.org/wiki/Machine_epsilon
432    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
433    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
434    #[rustc_diagnostic_item = "f32_epsilon"]
435    pub const EPSILON: f32 = 1.19209290e-07_f32;
436
437    /// Smallest finite `f32` value.
438    ///
439    /// Equal to &minus;[`MAX`].
440    ///
441    /// [`MAX`]: f32::MAX
442    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
443    pub const MIN: f32 = -3.40282347e+38_f32;
444    /// Smallest positive normal `f32` value.
445    ///
446    /// Equal to 2<sup>[`MIN_EXP`]&nbsp;&minus;&nbsp;1</sup>.
447    ///
448    /// [`MIN_EXP`]: f32::MIN_EXP
449    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
450    pub const MIN_POSITIVE: f32 = 1.17549435e-38_f32;
451    /// Largest finite `f32` value.
452    ///
453    /// Equal to
454    /// (1&nbsp;&minus;&nbsp;2<sup>&minus;[`MANTISSA_DIGITS`]</sup>)&nbsp;2<sup>[`MAX_EXP`]</sup>.
455    ///
456    /// [`MANTISSA_DIGITS`]: f32::MANTISSA_DIGITS
457    /// [`MAX_EXP`]: f32::MAX_EXP
458    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
459    pub const MAX: f32 = 3.40282347e+38_f32;
460
461    /// One greater than the minimum possible *normal* power of 2 exponent
462    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
463    ///
464    /// This corresponds to the exact minimum possible *normal* power of 2 exponent
465    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
466    /// In other words, all normal numbers representable by this type are
467    /// greater than or equal to 0.5&nbsp;×&nbsp;2<sup><i>MIN_EXP</i></sup>.
468    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
469    pub const MIN_EXP: i32 = -125;
470    /// One greater than the maximum possible power of 2 exponent
471    /// for a significand bounded by 1 ≤ x < 2 (i.e. the IEEE definition).
472    ///
473    /// This corresponds to the exact maximum possible power of 2 exponent
474    /// for a significand bounded by 0.5 ≤ x < 1 (i.e. the C definition).
475    /// In other words, all numbers representable by this type are
476    /// strictly less than 2<sup><i>MAX_EXP</i></sup>.
477    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
478    pub const MAX_EXP: i32 = 128;
479
480    /// Minimum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
481    ///
482    /// Equal to ceil(log<sub>10</sub>&nbsp;[`MIN_POSITIVE`]).
483    ///
484    /// [`MIN_POSITIVE`]: f32::MIN_POSITIVE
485    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
486    pub const MIN_10_EXP: i32 = -37;
487    /// Maximum <i>x</i> for which 10<sup><i>x</i></sup> is normal.
488    ///
489    /// Equal to floor(log<sub>10</sub>&nbsp;[`MAX`]).
490    ///
491    /// [`MAX`]: f32::MAX
492    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
493    pub const MAX_10_EXP: i32 = 38;
494
495    /// Not a Number (NaN).
496    ///
497    /// Note that IEEE 754 doesn't define just a single NaN value; a plethora of bit patterns are
498    /// considered to be NaN. Furthermore, the standard makes a difference between a "signaling" and
499    /// a "quiet" NaN, and allows inspecting its "payload" (the unspecified bits in the bit pattern)
500    /// and its sign. See the [specification of NaN bit patterns](f32#nan-bit-patterns) for more
501    /// info.
502    ///
503    /// This constant is guaranteed to be a quiet NaN (on targets that follow the Rust assumptions
504    /// that the quiet/signaling bit being set to 1 indicates a quiet NaN). Beyond that, nothing is
505    /// guaranteed about the specific bit pattern chosen here: both payload and sign are arbitrary.
506    /// The concrete bit pattern may change across Rust versions and target platforms.
507    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
508    #[rustc_diagnostic_item = "f32_nan"]
509    #[allow(clippy::eq_op)]
510    pub const NAN: f32 = 0.0_f32 / 0.0_f32;
511    /// Infinity (∞).
512    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
513    pub const INFINITY: f32 = 1.0_f32 / 0.0_f32;
514    /// Negative infinity (−∞).
515    #[stable(feature = "assoc_int_consts", since = "1.43.0")]
516    pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32;
517
518    /// Maximum integer that can be represented exactly in an [`f32`] value,
519    /// with no other integer converting to the same floating point value.
520    ///
521    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
522    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
523    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
524    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
525    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
526    /// "one-to-one" mapping.
527    ///
528    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
529    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
530    /// ```
531    /// #![feature(float_exact_integer_constants)]
532    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
533    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
534    /// let max_exact_int = f32::MAX_EXACT_INTEGER;
535    /// assert_eq!(max_exact_int, max_exact_int as f32 as i32);
536    /// assert_eq!(max_exact_int + 1, (max_exact_int + 1) as f32 as i32);
537    /// assert_ne!(max_exact_int + 2, (max_exact_int + 2) as f32 as i32);
538    ///
539    /// // Beyond `f32::MAX_EXACT_INTEGER`, multiple integers can map to one float value
540    /// assert_eq!((max_exact_int + 1) as f32, (max_exact_int + 2) as f32);
541    /// # }
542    /// ```
543    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
544    pub const MAX_EXACT_INTEGER: i32 = (1 << Self::MANTISSA_DIGITS) - 1;
545
546    /// Minimum integer that can be represented exactly in an [`f32`] value,
547    /// with no other integer converting to the same floating point value.
548    ///
549    /// For an integer `x` which satisfies `MIN_EXACT_INTEGER <= x <= MAX_EXACT_INTEGER`,
550    /// there is a "one-to-one" mapping between [`i32`] and [`f32`] values.
551    /// `MAX_EXACT_INTEGER + 1` also converts losslessly to [`f32`] and back to
552    /// [`i32`], but `MAX_EXACT_INTEGER + 2` converts to the same [`f32`] value
553    /// (and back to `MAX_EXACT_INTEGER + 1` as an integer) so there is not a
554    /// "one-to-one" mapping.
555    ///
556    /// This constant is equivalent to `-MAX_EXACT_INTEGER`.
557    ///
558    /// [`MAX_EXACT_INTEGER`]: f32::MAX_EXACT_INTEGER
559    /// [`MIN_EXACT_INTEGER`]: f32::MIN_EXACT_INTEGER
560    /// ```
561    /// #![feature(float_exact_integer_constants)]
562    /// # // FIXME(#152635): Float rounding on `i586` does not adhere to IEEE 754
563    /// # #[cfg(not(all(target_arch = "x86", not(target_feature = "sse"))))] {
564    /// let min_exact_int = f32::MIN_EXACT_INTEGER;
565    /// assert_eq!(min_exact_int, min_exact_int as f32 as i32);
566    /// assert_eq!(min_exact_int - 1, (min_exact_int - 1) as f32 as i32);
567    /// assert_ne!(min_exact_int - 2, (min_exact_int - 2) as f32 as i32);
568    ///
569    /// // Below `f32::MIN_EXACT_INTEGER`, multiple integers can map to one float value
570    /// assert_eq!((min_exact_int - 1) as f32, (min_exact_int - 2) as f32);
571    /// # }
572    /// ```
573    #[unstable(feature = "float_exact_integer_constants", issue = "152466")]
574    pub const MIN_EXACT_INTEGER: i32 = -Self::MAX_EXACT_INTEGER;
575
576    /// The mask of the bit used to encode the sign of an [`f32`].
577    ///
578    /// This bit is set when the sign is negative and unset when the sign is
579    /// positive.
580    /// If you only need to check whether a value is positive or negative,
581    /// [`is_sign_positive`] or [`is_sign_negative`] can be used.
582    ///
583    /// [`is_sign_positive`]: f32::is_sign_positive
584    /// [`is_sign_negative`]: f32::is_sign_negative
585    /// ```rust
586    /// #![feature(float_masks)]
587    /// let sign_mask = f32::SIGN_MASK;
588    /// let a = 1.6552f32;
589    /// let a_bits = a.to_bits();
590    ///
591    /// assert_eq!(a_bits & sign_mask, 0x0);
592    /// assert_eq!(f32::from_bits(a_bits ^ sign_mask), -a);
593    /// assert_eq!(sign_mask, (-0.0f32).to_bits());
594    /// ```
595    #[unstable(feature = "float_masks", issue = "154064")]
596    pub const SIGN_MASK: u32 = 0x8000_0000;
597
598    /// The mask of the bits used to encode the exponent of an [`f32`].
599    ///
600    /// Note that the exponent is stored as a biased value, with a bias of 127 for `f32`.
601    ///
602    /// ```rust
603    /// #![feature(float_masks)]
604    /// fn get_exp(a: f32) -> i32 {
605    ///     let bias = 127;
606    ///     let biased = a.to_bits() & f32::EXPONENT_MASK;
607    ///     (biased >> (f32::MANTISSA_DIGITS - 1)).cast_signed() - bias
608    /// }
609    ///
610    /// assert_eq!(get_exp(0.5), -1);
611    /// assert_eq!(get_exp(1.0), 0);
612    /// assert_eq!(get_exp(2.0), 1);
613    /// assert_eq!(get_exp(4.0), 2);
614    /// ```
615    #[unstable(feature = "float_masks", issue = "154064")]
616    pub const EXPONENT_MASK: u32 = 0x7f80_0000;
617
618    /// The mask of the bits used to encode the mantissa of an [`f32`].
619    ///
620    /// ```rust
621    /// #![feature(float_masks)]
622    /// let mantissa_mask = f32::MANTISSA_MASK;
623    ///
624    /// assert_eq!(0f32.to_bits() & mantissa_mask, 0x0);
625    /// assert_eq!(1f32.to_bits() & mantissa_mask, 0x0);
626    ///
627    /// // multiplying a finite value by a power of 2 doesn't change its mantissa
628    /// // unless the result or initial value is not normal.
629    /// let a = 1.6552f32;
630    /// let b = 4.0 * a;
631    /// assert_eq!(a.to_bits() & mantissa_mask, b.to_bits() & mantissa_mask);
632    ///
633    /// // The maximum and minimum values have a saturated significand
634    /// assert_eq!(f32::MAX.to_bits() & f32::MANTISSA_MASK, f32::MANTISSA_MASK);
635    /// assert_eq!(f32::MIN.to_bits() & f32::MANTISSA_MASK, f32::MANTISSA_MASK);
636    /// ```
637    #[unstable(feature = "float_masks", issue = "154064")]
638    pub const MANTISSA_MASK: u32 = 0x007f_ffff;
639
640    /// Minimum representable positive value (min subnormal)
641    const TINY_BITS: u32 = 0x1;
642
643    /// Minimum representable negative value (min negative subnormal)
644    const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK;
645
646    /// Returns `true` if this value is NaN.
647    ///
648    /// ```
649    /// let nan = f32::NAN;
650    /// let f = 7.0_f32;
651    ///
652    /// assert!(nan.is_nan());
653    /// assert!(!f.is_nan());
654    /// ```
655    #[must_use]
656    #[stable(feature = "rust1", since = "1.0.0")]
657    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
658    #[inline]
659    #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :)
660    #[ferrocene::prevalidated]
661    pub const fn is_nan(self) -> bool {
662        self != self
663    }
664
665    /// Returns `true` if this value is positive infinity or negative infinity, and
666    /// `false` otherwise.
667    ///
668    /// ```
669    /// let f = 7.0f32;
670    /// let inf = f32::INFINITY;
671    /// let neg_inf = f32::NEG_INFINITY;
672    /// let nan = f32::NAN;
673    ///
674    /// assert!(!f.is_infinite());
675    /// assert!(!nan.is_infinite());
676    ///
677    /// assert!(inf.is_infinite());
678    /// assert!(neg_inf.is_infinite());
679    /// ```
680    #[must_use]
681    #[stable(feature = "rust1", since = "1.0.0")]
682    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
683    #[inline]
684    #[ferrocene::prevalidated]
685    pub const fn is_infinite(self) -> bool {
686        // Getting clever with transmutation can result in incorrect answers on some FPUs
687        // FIXME: alter the Rust <-> Rust calling convention to prevent this problem.
688        // See https://github.com/rust-lang/rust/issues/72327
689        (self == f32::INFINITY) | (self == f32::NEG_INFINITY)
690    }
691
692    /// Returns `true` if this number is neither infinite nor NaN.
693    ///
694    /// ```
695    /// let f = 7.0f32;
696    /// let inf = f32::INFINITY;
697    /// let neg_inf = f32::NEG_INFINITY;
698    /// let nan = f32::NAN;
699    ///
700    /// assert!(f.is_finite());
701    ///
702    /// assert!(!nan.is_finite());
703    /// assert!(!inf.is_finite());
704    /// assert!(!neg_inf.is_finite());
705    /// ```
706    #[must_use]
707    #[stable(feature = "rust1", since = "1.0.0")]
708    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
709    #[inline]
710    pub const fn is_finite(self) -> bool {
711        // There's no need to handle NaN separately: if self is NaN,
712        // the comparison is not true, exactly as desired.
713        self.abs() < Self::INFINITY
714    }
715
716    /// Returns `true` if the number is [subnormal].
717    ///
718    /// ```
719    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
720    /// let max = f32::MAX;
721    /// let lower_than_min = 1.0e-40_f32;
722    /// let zero = 0.0_f32;
723    ///
724    /// assert!(!min.is_subnormal());
725    /// assert!(!max.is_subnormal());
726    ///
727    /// assert!(!zero.is_subnormal());
728    /// assert!(!f32::NAN.is_subnormal());
729    /// assert!(!f32::INFINITY.is_subnormal());
730    /// // Values between `0` and `min` are Subnormal.
731    /// assert!(lower_than_min.is_subnormal());
732    /// ```
733    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
734    #[must_use]
735    #[stable(feature = "is_subnormal", since = "1.53.0")]
736    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
737    #[inline]
738    pub const fn is_subnormal(self) -> bool {
739        matches!(self.classify(), FpCategory::Subnormal)
740    }
741
742    /// Returns `true` if the number is neither zero, infinite,
743    /// [subnormal], or NaN.
744    ///
745    /// ```
746    /// let min = f32::MIN_POSITIVE; // 1.17549435e-38f32
747    /// let max = f32::MAX;
748    /// let lower_than_min = 1.0e-40_f32;
749    /// let zero = 0.0_f32;
750    ///
751    /// assert!(min.is_normal());
752    /// assert!(max.is_normal());
753    ///
754    /// assert!(!zero.is_normal());
755    /// assert!(!f32::NAN.is_normal());
756    /// assert!(!f32::INFINITY.is_normal());
757    /// // Values between `0` and `min` are Subnormal.
758    /// assert!(!lower_than_min.is_normal());
759    /// ```
760    /// [subnormal]: https://en.wikipedia.org/wiki/Denormal_number
761    #[must_use]
762    #[stable(feature = "rust1", since = "1.0.0")]
763    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
764    #[inline]
765    pub const fn is_normal(self) -> bool {
766        matches!(self.classify(), FpCategory::Normal)
767    }
768
769    /// Returns the floating point category of the number. If only one property
770    /// is going to be tested, it is generally faster to use the specific
771    /// predicate instead.
772    ///
773    /// ```
774    /// use std::num::FpCategory;
775    ///
776    /// let num = 12.4_f32;
777    /// let inf = f32::INFINITY;
778    ///
779    /// assert_eq!(num.classify(), FpCategory::Normal);
780    /// assert_eq!(inf.classify(), FpCategory::Infinite);
781    /// ```
782    #[ferrocene::prevalidated]
783    #[stable(feature = "rust1", since = "1.0.0")]
784    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
785    #[must_use]
786    pub const fn classify(self) -> FpCategory {
787        // We used to have complicated logic here that avoids the simple bit-based tests to work
788        // around buggy codegen for x87 targets (see
789        // https://github.com/rust-lang/rust/issues/114479). However, some LLVM versions later, none
790        // of our tests is able to find any difference between the complicated and the naive
791        // version, so now we are back to the naive version.
792        let b = self.to_bits();
793        match (b & Self::MANTISSA_MASK, b & Self::EXPONENT_MASK) {
794            (0, Self::EXPONENT_MASK) => FpCategory::Infinite,
795            (_, Self::EXPONENT_MASK) => FpCategory::Nan,
796            (0, 0) => FpCategory::Zero,
797            (_, 0) => FpCategory::Subnormal,
798            _ => FpCategory::Normal,
799        }
800    }
801
802    /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with
803    /// positive sign bit and positive infinity.
804    ///
805    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
806    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
807    /// conserved over arithmetic operations, the result of `is_sign_positive` on
808    /// a NaN might produce an unexpected or non-portable result. See the [specification
809    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == 1.0`
810    /// if you need fully portable behavior (will return `false` for all NaNs).
811    ///
812    /// ```
813    /// let f = 7.0_f32;
814    /// let g = -7.0_f32;
815    ///
816    /// assert!(f.is_sign_positive());
817    /// assert!(!g.is_sign_positive());
818    /// ```
819    #[must_use]
820    #[stable(feature = "rust1", since = "1.0.0")]
821    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
822    #[inline]
823    pub const fn is_sign_positive(self) -> bool {
824        !self.is_sign_negative()
825    }
826
827    /// Returns `true` if `self` has a negative sign, including `-0.0`, NaNs with
828    /// negative sign bit and negative infinity.
829    ///
830    /// Note that IEEE 754 doesn't assign any meaning to the sign bit in case of
831    /// a NaN, and as Rust doesn't guarantee that the bit pattern of NaNs are
832    /// conserved over arithmetic operations, the result of `is_sign_negative` on
833    /// a NaN might produce an unexpected or non-portable result. See the [specification
834    /// of NaN bit patterns](f32#nan-bit-patterns) for more info. Use `self.signum() == -1.0`
835    /// if you need fully portable behavior (will return `false` for all NaNs).
836    ///
837    /// ```
838    /// let f = 7.0f32;
839    /// let g = -7.0f32;
840    ///
841    /// assert!(!f.is_sign_negative());
842    /// assert!(g.is_sign_negative());
843    /// ```
844    #[must_use]
845    #[stable(feature = "rust1", since = "1.0.0")]
846    #[rustc_const_stable(feature = "const_float_classify", since = "1.83.0")]
847    #[inline]
848    #[ferrocene::prevalidated]
849    pub const fn is_sign_negative(self) -> bool {
850        // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus
851        // applies to zeros and NaNs as well.
852        self.to_bits() & 0x8000_0000 != 0
853    }
854
855    /// Returns the least number greater than `self`.
856    ///
857    /// Let `TINY` be the smallest representable positive `f32`. Then,
858    ///  - if `self.is_nan()`, this returns `self`;
859    ///  - if `self` is [`NEG_INFINITY`], this returns [`MIN`];
860    ///  - if `self` is `-TINY`, this returns -0.0;
861    ///  - if `self` is -0.0 or +0.0, this returns `TINY`;
862    ///  - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`];
863    ///  - otherwise the unique least value greater than `self` is returned.
864    ///
865    /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x`
866    /// is finite `x == x.next_up().next_down()` also holds.
867    ///
868    /// ```rust
869    /// // f32::EPSILON is the difference between 1.0 and the next number up.
870    /// assert_eq!(1.0f32.next_up(), 1.0 + f32::EPSILON);
871    /// // But not for most numbers.
872    /// assert!(0.1f32.next_up() < 0.1 + f32::EPSILON);
873    /// assert_eq!(16777216f32.next_up(), 16777218.0);
874    /// ```
875    ///
876    /// This operation corresponds to IEEE-754 `nextUp`.
877    ///
878    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
879    /// [`INFINITY`]: Self::INFINITY
880    /// [`MIN`]: Self::MIN
881    /// [`MAX`]: Self::MAX
882    #[inline]
883    #[doc(alias = "nextUp")]
884    #[stable(feature = "float_next_up_down", since = "1.86.0")]
885    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
886    #[must_use = "method returns a new number and does not mutate the original value"]
887    pub const fn next_up(self) -> Self {
888        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
889        // denormals to zero. This is in general unsound and unsupported, but here
890        // we do our best to still produce the correct result on such targets.
891        let bits = self.to_bits();
892        if self.is_nan() || bits == Self::INFINITY.to_bits() {
893            return self;
894        }
895
896        let abs = bits & !Self::SIGN_MASK;
897        let next_bits = if abs == 0 {
898            Self::TINY_BITS
899        } else if bits == abs {
900            bits + 1
901        } else {
902            bits - 1
903        };
904        Self::from_bits(next_bits)
905    }
906
907    /// Returns the greatest number less than `self`.
908    ///
909    /// Let `TINY` be the smallest representable positive `f32`. Then,
910    ///  - if `self.is_nan()`, this returns `self`;
911    ///  - if `self` is [`INFINITY`], this returns [`MAX`];
912    ///  - if `self` is `TINY`, this returns 0.0;
913    ///  - if `self` is -0.0 or +0.0, this returns `-TINY`;
914    ///  - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`];
915    ///  - otherwise the unique greatest value less than `self` is returned.
916    ///
917    /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x`
918    /// is finite `x == x.next_down().next_up()` also holds.
919    ///
920    /// ```rust
921    /// let x = 1.0f32;
922    /// // Clamp value into range [0, 1).
923    /// let clamped = x.clamp(0.0, 1.0f32.next_down());
924    /// assert!(clamped < 1.0);
925    /// assert_eq!(clamped.next_up(), 1.0);
926    /// ```
927    ///
928    /// This operation corresponds to IEEE-754 `nextDown`.
929    ///
930    /// [`NEG_INFINITY`]: Self::NEG_INFINITY
931    /// [`INFINITY`]: Self::INFINITY
932    /// [`MIN`]: Self::MIN
933    /// [`MAX`]: Self::MAX
934    #[inline]
935    #[doc(alias = "nextDown")]
936    #[stable(feature = "float_next_up_down", since = "1.86.0")]
937    #[rustc_const_stable(feature = "float_next_up_down", since = "1.86.0")]
938    #[must_use = "method returns a new number and does not mutate the original value"]
939    pub const fn next_down(self) -> Self {
940        // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing
941        // denormals to zero. This is in general unsound and unsupported, but here
942        // we do our best to still produce the correct result on such targets.
943        let bits = self.to_bits();
944        if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() {
945            return self;
946        }
947
948        let abs = bits & !Self::SIGN_MASK;
949        let next_bits = if abs == 0 {
950            Self::NEG_TINY_BITS
951        } else if bits == abs {
952            bits - 1
953        } else {
954            bits + 1
955        };
956        Self::from_bits(next_bits)
957    }
958
959    /// Takes the reciprocal (inverse) of a number, `1/x`.
960    ///
961    /// ```
962    /// let x = 2.0_f32;
963    /// let abs_difference = (x.recip() - (1.0 / x)).abs();
964    ///
965    /// assert!(abs_difference <= f32::EPSILON);
966    /// ```
967    #[must_use = "this returns the result of the operation, without modifying the original"]
968    #[stable(feature = "rust1", since = "1.0.0")]
969    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
970    #[inline]
971    pub const fn recip(self) -> f32 {
972        1.0 / self
973    }
974
975    /// Converts radians to degrees.
976    ///
977    /// # Unspecified precision
978    ///
979    /// The precision of this function is non-deterministic. This means it varies by platform,
980    /// Rust version, and can even differ within the same execution from one invocation to the next.
981    ///
982    /// # Examples
983    ///
984    /// ```
985    /// let angle = std::f32::consts::PI;
986    ///
987    /// let abs_difference = (angle.to_degrees() - 180.0).abs();
988    /// # #[cfg(any(not(target_arch = "x86"), target_feature = "sse2"))]
989    /// assert!(abs_difference <= f32::EPSILON);
990    /// ```
991    #[must_use = "this returns the result of the operation, \
992                  without modifying the original"]
993    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
994    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
995    #[inline]
996    pub const fn to_degrees(self) -> f32 {
997        // Use a literal to avoid double rounding, consts::PI is already rounded,
998        // and dividing would round again.
999        const PIS_IN_180: f32 = 57.2957795130823208767981548141051703_f32;
1000        self * PIS_IN_180
1001    }
1002
1003    /// Converts degrees to radians.
1004    ///
1005    /// # Unspecified precision
1006    ///
1007    /// The precision of this function is non-deterministic. This means it varies by platform,
1008    /// Rust version, and can even differ within the same execution from one invocation to the next.
1009    ///
1010    /// # Examples
1011    ///
1012    /// ```
1013    /// let angle = 180.0f32;
1014    ///
1015    /// let abs_difference = (angle.to_radians() - std::f32::consts::PI).abs();
1016    ///
1017    /// assert!(abs_difference <= f32::EPSILON);
1018    /// ```
1019    #[must_use = "this returns the result of the operation, \
1020                  without modifying the original"]
1021    #[stable(feature = "f32_deg_rad_conversions", since = "1.7.0")]
1022    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1023    #[inline]
1024    pub const fn to_radians(self) -> f32 {
1025        // The division here is correctly rounded with respect to the true value of π/180.
1026        // Although π is irrational and already rounded, the double rounding happens
1027        // to produce correct result for f32.
1028        const RADS_PER_DEG: f32 = consts::PI / 180.0;
1029        self * RADS_PER_DEG
1030    }
1031
1032    /// Returns the maximum of the two numbers, ignoring NaN.
1033    ///
1034    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1035    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1036    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1037    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1038    /// non-deterministically.
1039    ///
1040    /// The handling of NaNs follows the IEEE 754-2019 semantics for `maximumNumber`, treating all
1041    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1042    /// follows the IEEE 754-2008 semantics for `maxNum`.
1043    ///
1044    /// ```
1045    /// let x = 1.0f32;
1046    /// let y = 2.0f32;
1047    ///
1048    /// assert_eq!(x.max(y), y);
1049    /// assert_eq!(x.max(f32::NAN), x);
1050    /// ```
1051    #[must_use = "this returns the result of the comparison, without modifying either input"]
1052    #[stable(feature = "rust1", since = "1.0.0")]
1053    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1054    #[inline]
1055    #[ferrocene::prevalidated]
1056    pub const fn max(self, other: f32) -> f32 {
1057        intrinsics::maximum_number_nsz_f32(self, other)
1058    }
1059
1060    /// Returns the minimum of the two numbers, ignoring NaN.
1061    ///
1062    /// If exactly one of the arguments is NaN (quiet or signaling), then the other argument is
1063    /// returned. If both arguments are NaN, the return value is NaN, with the bit pattern picked
1064    /// using the usual [rules for arithmetic operations](f32#nan-bit-patterns). If the inputs
1065    /// compare equal (such as for the case of `+0.0` and `-0.0`), either input may be returned
1066    /// non-deterministically.
1067    ///
1068    /// The handling of NaNs follows the IEEE 754-2019 semantics for `minimumNumber`, treating all
1069    /// NaNs the same way to ensure the operation is associative. The handling of signed zeros
1070    /// follows the IEEE 754-2008 semantics for `minNum`.
1071    ///
1072    /// ```
1073    /// let x = 1.0f32;
1074    /// let y = 2.0f32;
1075    ///
1076    /// assert_eq!(x.min(y), x);
1077    /// assert_eq!(x.min(f32::NAN), x);
1078    /// ```
1079    #[must_use = "this returns the result of the comparison, without modifying either input"]
1080    #[stable(feature = "rust1", since = "1.0.0")]
1081    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1082    #[inline]
1083    #[ferrocene::prevalidated]
1084    pub const fn min(self, other: f32) -> f32 {
1085        intrinsics::minimum_number_nsz_f32(self, other)
1086    }
1087
1088    /// Returns the maximum of the two numbers, propagating NaN.
1089    ///
1090    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1091    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1092    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1093    /// non-NaN inputs.
1094    ///
1095    /// This is in contrast to [`f32::max`] which only returns NaN when *both* arguments are NaN,
1096    /// and which does not reliably order `-0.0` and `+0.0`.
1097    ///
1098    /// This follows the IEEE 754-2019 semantics for `maximum`.
1099    ///
1100    /// ```
1101    /// #![feature(float_minimum_maximum)]
1102    /// let x = 1.0f32;
1103    /// let y = 2.0f32;
1104    ///
1105    /// assert_eq!(x.maximum(y), y);
1106    /// assert!(x.maximum(f32::NAN).is_nan());
1107    /// ```
1108    #[must_use = "this returns the result of the comparison, without modifying either input"]
1109    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1110    #[inline]
1111    pub const fn maximum(self, other: f32) -> f32 {
1112        intrinsics::maximumf32(self, other)
1113    }
1114
1115    /// Returns the minimum of the two numbers, propagating NaN.
1116    ///
1117    /// If at least one of the arguments is NaN, the return value is NaN, with the bit pattern
1118    /// picked using the usual [rules for arithmetic operations](f32#nan-bit-patterns). Furthermore,
1119    /// `-0.0` is considered to be less than `+0.0`, making this function fully deterministic for
1120    /// non-NaN inputs.
1121    ///
1122    /// This is in contrast to [`f32::min`] which only returns NaN when *both* arguments are NaN,
1123    /// and which does not reliably order `-0.0` and `+0.0`.
1124    ///
1125    /// This follows the IEEE 754-2019 semantics for `minimum`.
1126    ///
1127    /// ```
1128    /// #![feature(float_minimum_maximum)]
1129    /// let x = 1.0f32;
1130    /// let y = 2.0f32;
1131    ///
1132    /// assert_eq!(x.minimum(y), x);
1133    /// assert!(x.minimum(f32::NAN).is_nan());
1134    /// ```
1135    #[must_use = "this returns the result of the comparison, without modifying either input"]
1136    #[unstable(feature = "float_minimum_maximum", issue = "91079")]
1137    #[inline]
1138    pub const fn minimum(self, other: f32) -> f32 {
1139        intrinsics::minimumf32(self, other)
1140    }
1141
1142    /// Calculates the midpoint (average) between `self` and `rhs`.
1143    ///
1144    /// This returns NaN when *either* argument is NaN or if a combination of
1145    /// +inf and -inf is provided as arguments.
1146    ///
1147    /// # Examples
1148    ///
1149    /// ```
1150    /// assert_eq!(1f32.midpoint(4.0), 2.5);
1151    /// assert_eq!((-5.5f32).midpoint(8.0), 1.25);
1152    /// ```
1153    #[inline]
1154    #[doc(alias = "average")]
1155    #[stable(feature = "num_midpoint", since = "1.85.0")]
1156    #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1157    #[must_use = "this returns the result of the operation, \
1158                  without modifying the original"]
1159    pub const fn midpoint(self, other: f32) -> f32 {
1160        cfg_select! {
1161            // Allow faster implementation that have known good 64-bit float
1162            // implementations. Falling back to the branchy code on targets that don't
1163            // have 64-bit hardware floats or buggy implementations.
1164            // https://github.com/rust-lang/rust/pull/121062#issuecomment-2123408114
1165            any(
1166                target_arch = "x86_64",
1167                target_arch = "aarch64",
1168                all(any(target_arch = "riscv32", target_arch = "riscv64"), target_feature = "d"),
1169                all(target_arch = "loongarch64", target_feature = "d"),
1170                all(target_arch = "arm", target_feature = "vfp2"),
1171                target_arch = "wasm32",
1172                target_arch = "wasm64",
1173            ) => {
1174                ((self as f64 + other as f64) * 0.5) as f32
1175            }
1176            _ => {
1177                const HI: f32 = f32::MAX * 0.5;
1178
1179                let (a, b) = (self, other);
1180                let abs_a = a.abs();
1181                let abs_b = b.abs();
1182
1183                if abs_a <= HI && abs_b <= HI {
1184                    // Overflow is impossible
1185                    (a + b) * 0.5
1186                } else {
1187                    (a * 0.5) + (b * 0.5)
1188                }
1189            }
1190        }
1191    }
1192
1193    /// Rounds toward zero and converts to any primitive integer type,
1194    /// assuming that the value is finite and fits in that type.
1195    ///
1196    /// ```
1197    /// let value = 4.6_f32;
1198    /// let rounded = unsafe { value.to_int_unchecked::<u16>() };
1199    /// assert_eq!(rounded, 4);
1200    ///
1201    /// let value = -128.9_f32;
1202    /// let rounded = unsafe { value.to_int_unchecked::<i8>() };
1203    /// assert_eq!(rounded, i8::MIN);
1204    /// ```
1205    ///
1206    /// # Safety
1207    ///
1208    /// The value must:
1209    ///
1210    /// * Not be `NaN`
1211    /// * Not be infinite
1212    /// * Be representable in the return type `Int`, after truncating off its fractional part
1213    #[must_use = "this returns the result of the operation, \
1214                  without modifying the original"]
1215    #[stable(feature = "float_approx_unchecked_to", since = "1.44.0")]
1216    #[inline]
1217    pub unsafe fn to_int_unchecked<Int>(self) -> Int
1218    where
1219        Self: FloatToInt<Int>,
1220    {
1221        // SAFETY: the caller must uphold the safety contract for
1222        // `FloatToInt::to_int_unchecked`.
1223        unsafe { FloatToInt::<Int>::to_int_unchecked(self) }
1224    }
1225
1226    /// Raw transmutation to `u32`.
1227    ///
1228    /// This is currently identical to `transmute::<f32, u32>(self)` on all platforms.
1229    ///
1230    /// See [`from_bits`](Self::from_bits) for some discussion of the
1231    /// portability of this operation (there are almost no issues).
1232    ///
1233    /// Note that this function is distinct from `as` casting, which attempts to
1234    /// preserve the *numeric* value, and not the bitwise value.
1235    ///
1236    /// # Examples
1237    ///
1238    /// ```
1239    /// assert_ne!((1f32).to_bits(), 1f32 as u32); // to_bits() is not casting!
1240    /// assert_eq!((12.5f32).to_bits(), 0x41480000);
1241    ///
1242    /// ```
1243    #[must_use = "this returns the result of the operation, \
1244                  without modifying the original"]
1245    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1246    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1247    #[inline]
1248    #[allow(unnecessary_transmutes)]
1249    #[ferrocene::prevalidated]
1250    pub const fn to_bits(self) -> u32 {
1251        // SAFETY: `u32` is a plain old datatype so we can always transmute to it.
1252        unsafe { mem::transmute(self) }
1253    }
1254
1255    /// Raw transmutation from `u32`.
1256    ///
1257    /// This is currently identical to `transmute::<u32, f32>(v)` on all platforms.
1258    /// It turns out this is incredibly portable, for two reasons:
1259    ///
1260    /// * Floats and Ints have the same endianness on all supported platforms.
1261    /// * IEEE 754 very precisely specifies the bit layout of floats.
1262    ///
1263    /// However there is one caveat: prior to the 2008 version of IEEE 754, how
1264    /// to interpret the NaN signaling bit wasn't actually specified. Most platforms
1265    /// (notably x86 and ARM) picked the interpretation that was ultimately
1266    /// standardized in 2008, but some didn't (notably MIPS). As a result, all
1267    /// signaling NaNs on MIPS are quiet NaNs on x86, and vice-versa.
1268    ///
1269    /// Rather than trying to preserve signaling-ness cross-platform, this
1270    /// implementation favors preserving the exact bits. This means that
1271    /// any payloads encoded in NaNs will be preserved even if the result of
1272    /// this method is sent over the network from an x86 machine to a MIPS one.
1273    ///
1274    /// If the results of this method are only manipulated by the same
1275    /// architecture that produced them, then there is no portability concern.
1276    ///
1277    /// If the input isn't NaN, then there is no portability concern.
1278    ///
1279    /// If you don't care about signalingness (very likely), then there is no
1280    /// portability concern.
1281    ///
1282    /// Note that this function is distinct from `as` casting, which attempts to
1283    /// preserve the *numeric* value, and not the bitwise value.
1284    ///
1285    /// # Examples
1286    ///
1287    /// ```
1288    /// let v = f32::from_bits(0x41480000);
1289    /// assert_eq!(v, 12.5);
1290    /// ```
1291    #[stable(feature = "float_bits_conv", since = "1.20.0")]
1292    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1293    #[must_use]
1294    #[inline]
1295    #[allow(unnecessary_transmutes)]
1296    #[ferrocene::prevalidated]
1297    pub const fn from_bits(v: u32) -> Self {
1298        // It turns out the safety issues with sNaN were overblown! Hooray!
1299        // SAFETY: `u32` is a plain old datatype so we can always transmute from it.
1300        unsafe { mem::transmute(v) }
1301    }
1302
1303    /// Returns the memory representation of this floating point number as a byte array in
1304    /// big-endian (network) byte order.
1305    ///
1306    /// See [`from_bits`](Self::from_bits) for some discussion of the
1307    /// portability of this operation (there are almost no issues).
1308    ///
1309    /// # Examples
1310    ///
1311    /// ```
1312    /// let bytes = 12.5f32.to_be_bytes();
1313    /// assert_eq!(bytes, [0x41, 0x48, 0x00, 0x00]);
1314    /// ```
1315    #[must_use = "this returns the result of the operation, \
1316                  without modifying the original"]
1317    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1318    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1319    #[inline]
1320    pub const fn to_be_bytes(self) -> [u8; 4] {
1321        self.to_bits().to_be_bytes()
1322    }
1323
1324    /// Returns the memory representation of this floating point number as a byte array in
1325    /// little-endian byte order.
1326    ///
1327    /// See [`from_bits`](Self::from_bits) for some discussion of the
1328    /// portability of this operation (there are almost no issues).
1329    ///
1330    /// # Examples
1331    ///
1332    /// ```
1333    /// let bytes = 12.5f32.to_le_bytes();
1334    /// assert_eq!(bytes, [0x00, 0x00, 0x48, 0x41]);
1335    /// ```
1336    #[must_use = "this returns the result of the operation, \
1337                  without modifying the original"]
1338    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1339    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1340    #[inline]
1341    #[ferrocene::prevalidated]
1342    pub const fn to_le_bytes(self) -> [u8; 4] {
1343        self.to_bits().to_le_bytes()
1344    }
1345
1346    /// Returns the memory representation of this floating point number as a byte array in
1347    /// native byte order.
1348    ///
1349    /// As the target platform's native endianness is used, portable code
1350    /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead.
1351    ///
1352    /// [`to_be_bytes`]: f32::to_be_bytes
1353    /// [`to_le_bytes`]: f32::to_le_bytes
1354    ///
1355    /// See [`from_bits`](Self::from_bits) for some discussion of the
1356    /// portability of this operation (there are almost no issues).
1357    ///
1358    /// # Examples
1359    ///
1360    /// ```
1361    /// let bytes = 12.5f32.to_ne_bytes();
1362    /// assert_eq!(
1363    ///     bytes,
1364    ///     if cfg!(target_endian = "big") {
1365    ///         [0x41, 0x48, 0x00, 0x00]
1366    ///     } else {
1367    ///         [0x00, 0x00, 0x48, 0x41]
1368    ///     }
1369    /// );
1370    /// ```
1371    #[must_use = "this returns the result of the operation, \
1372                  without modifying the original"]
1373    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1374    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1375    #[inline]
1376    pub const fn to_ne_bytes(self) -> [u8; 4] {
1377        self.to_bits().to_ne_bytes()
1378    }
1379
1380    /// Creates a floating point value from its representation as a byte array in big endian.
1381    ///
1382    /// See [`from_bits`](Self::from_bits) for some discussion of the
1383    /// portability of this operation (there are almost no issues).
1384    ///
1385    /// # Examples
1386    ///
1387    /// ```
1388    /// let value = f32::from_be_bytes([0x41, 0x48, 0x00, 0x00]);
1389    /// assert_eq!(value, 12.5);
1390    /// ```
1391    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1392    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1393    #[must_use]
1394    #[inline]
1395    pub const fn from_be_bytes(bytes: [u8; 4]) -> Self {
1396        Self::from_bits(u32::from_be_bytes(bytes))
1397    }
1398
1399    /// Creates a floating point value from its representation as a byte array in little endian.
1400    ///
1401    /// See [`from_bits`](Self::from_bits) for some discussion of the
1402    /// portability of this operation (there are almost no issues).
1403    ///
1404    /// # Examples
1405    ///
1406    /// ```
1407    /// let value = f32::from_le_bytes([0x00, 0x00, 0x48, 0x41]);
1408    /// assert_eq!(value, 12.5);
1409    /// ```
1410    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1411    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1412    #[must_use]
1413    #[inline]
1414    #[ferrocene::prevalidated]
1415    pub const fn from_le_bytes(bytes: [u8; 4]) -> Self {
1416        Self::from_bits(u32::from_le_bytes(bytes))
1417    }
1418
1419    /// Creates a floating point value from its representation as a byte array in native endian.
1420    ///
1421    /// As the target platform's native endianness is used, portable code
1422    /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
1423    /// appropriate instead.
1424    ///
1425    /// [`from_be_bytes`]: f32::from_be_bytes
1426    /// [`from_le_bytes`]: f32::from_le_bytes
1427    ///
1428    /// See [`from_bits`](Self::from_bits) for some discussion of the
1429    /// portability of this operation (there are almost no issues).
1430    ///
1431    /// # Examples
1432    ///
1433    /// ```
1434    /// let value = f32::from_ne_bytes(if cfg!(target_endian = "big") {
1435    ///     [0x41, 0x48, 0x00, 0x00]
1436    /// } else {
1437    ///     [0x00, 0x00, 0x48, 0x41]
1438    /// });
1439    /// assert_eq!(value, 12.5);
1440    /// ```
1441    #[stable(feature = "float_to_from_bytes", since = "1.40.0")]
1442    #[rustc_const_stable(feature = "const_float_bits_conv", since = "1.83.0")]
1443    #[must_use]
1444    #[inline]
1445    pub const fn from_ne_bytes(bytes: [u8; 4]) -> Self {
1446        Self::from_bits(u32::from_ne_bytes(bytes))
1447    }
1448
1449    /// Returns the ordering between `self` and `other`.
1450    ///
1451    /// Unlike the standard partial comparison between floating point numbers,
1452    /// this comparison always produces an ordering in accordance to
1453    /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision)
1454    /// floating point standard. The values are ordered in the following sequence:
1455    ///
1456    /// - negative quiet NaN
1457    /// - negative signaling NaN
1458    /// - negative infinity
1459    /// - negative numbers
1460    /// - negative subnormal numbers
1461    /// - negative zero
1462    /// - positive zero
1463    /// - positive subnormal numbers
1464    /// - positive numbers
1465    /// - positive infinity
1466    /// - positive signaling NaN
1467    /// - positive quiet NaN.
1468    ///
1469    /// The ordering established by this function does not always agree with the
1470    /// [`PartialOrd`] and [`PartialEq`] implementations of `f32`. For example,
1471    /// they consider negative and positive zero equal, while `total_cmp`
1472    /// doesn't.
1473    ///
1474    /// The interpretation of the signaling NaN bit follows the definition in
1475    /// the IEEE 754 standard, which may not match the interpretation by some of
1476    /// the older, non-conformant (e.g. MIPS) hardware implementations.
1477    ///
1478    /// # Example
1479    ///
1480    /// ```
1481    /// struct GoodBoy {
1482    ///     name: String,
1483    ///     weight: f32,
1484    /// }
1485    ///
1486    /// let mut bois = vec![
1487    ///     GoodBoy { name: "Pucci".to_owned(), weight: 0.1 },
1488    ///     GoodBoy { name: "Woofer".to_owned(), weight: 99.0 },
1489    ///     GoodBoy { name: "Yapper".to_owned(), weight: 10.0 },
1490    ///     GoodBoy { name: "Chonk".to_owned(), weight: f32::INFINITY },
1491    ///     GoodBoy { name: "Abs. Unit".to_owned(), weight: f32::NAN },
1492    ///     GoodBoy { name: "Floaty".to_owned(), weight: -5.0 },
1493    /// ];
1494    ///
1495    /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight));
1496    ///
1497    /// // `f32::NAN` could be positive or negative, which will affect the sort order.
1498    /// if f32::NAN.is_sign_negative() {
1499    ///     assert!(bois.into_iter().map(|b| b.weight)
1500    ///         .zip([f32::NAN, -5.0, 0.1, 10.0, 99.0, f32::INFINITY].iter())
1501    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1502    /// } else {
1503    ///     assert!(bois.into_iter().map(|b| b.weight)
1504    ///         .zip([-5.0, 0.1, 10.0, 99.0, f32::INFINITY, f32::NAN].iter())
1505    ///         .all(|(a, b)| a.to_bits() == b.to_bits()))
1506    /// }
1507    /// ```
1508    #[stable(feature = "total_cmp", since = "1.62.0")]
1509    #[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
1510    #[must_use]
1511    #[inline]
1512    pub const fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering {
1513        let mut left = self.to_bits() as i32;
1514        let mut right = other.to_bits() as i32;
1515
1516        // In case of negatives, flip all the bits except the sign
1517        // to achieve a similar layout as two's complement integers
1518        //
1519        // Why does this work? IEEE 754 floats consist of three fields:
1520        // Sign bit, exponent and mantissa. The set of exponent and mantissa
1521        // fields as a whole have the property that their bitwise order is
1522        // equal to the numeric magnitude where the magnitude is defined.
1523        // The magnitude is not normally defined on NaN values, but
1524        // IEEE 754 totalOrder defines the NaN values also to follow the
1525        // bitwise order. This leads to order explained in the doc comment.
1526        // However, the representation of magnitude is the same for negative
1527        // and positive numbers – only the sign bit is different.
1528        // To easily compare the floats as signed integers, we need to
1529        // flip the exponent and mantissa bits in case of negative numbers.
1530        // We effectively convert the numbers to "two's complement" form.
1531        //
1532        // To do the flipping, we construct a mask and XOR against it.
1533        // We branchlessly calculate an "all-ones except for the sign bit"
1534        // mask from negative-signed values: right shifting sign-extends
1535        // the integer, so we "fill" the mask with sign bits, and then
1536        // convert to unsigned to push one more zero bit.
1537        // On positive values, the mask is all zeros, so it's a no-op.
1538        left ^= (((left >> 31) as u32) >> 1) as i32;
1539        right ^= (((right >> 31) as u32) >> 1) as i32;
1540
1541        left.cmp(&right)
1542    }
1543
1544    /// Restrict a value to a certain interval unless it is NaN.
1545    ///
1546    /// Returns `max` if `self` is greater than `max`, and `min` if `self` is
1547    /// less than `min`. Otherwise this returns `self`.
1548    ///
1549    /// Note that this function returns NaN if the initial value was NaN as
1550    /// well. If the result is zero and among the three inputs `self`, `min`, and `max` there are
1551    /// zeros with different sign, either `0.0` or `-0.0` is returned non-deterministically.
1552    ///
1553    /// # Panics
1554    ///
1555    /// Panics if `min > max`, `min` is NaN, or `max` is NaN.
1556    ///
1557    /// # Examples
1558    ///
1559    /// ```
1560    /// assert!((-3.0f32).clamp(-2.0, 1.0) == -2.0);
1561    /// assert!((0.0f32).clamp(-2.0, 1.0) == 0.0);
1562    /// assert!((2.0f32).clamp(-2.0, 1.0) == 1.0);
1563    /// assert!((f32::NAN).clamp(-2.0, 1.0).is_nan());
1564    ///
1565    /// // These always returns zero, but the sign (which is ignored by `==`) is non-deterministic.
1566    /// assert!((0.0f32).clamp(-0.0, -0.0) == 0.0);
1567    /// assert!((1.0f32).clamp(-0.0, 0.0) == 0.0);
1568    /// // This is definitely a negative zero.
1569    /// assert!((-1.0f32).clamp(-0.0, 1.0).is_sign_negative());
1570    /// ```
1571    #[must_use = "method returns a new number and does not mutate the original value"]
1572    #[stable(feature = "clamp", since = "1.50.0")]
1573    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1574    #[inline]
1575    pub const fn clamp(mut self, min: f32, max: f32) -> f32 {
1576        const_assert!(
1577            min <= max,
1578            "min > max, or either was NaN",
1579            "min > max, or either was NaN. min = {min:?}, max = {max:?}",
1580            min: f32,
1581            max: f32,
1582        );
1583
1584        if self < min {
1585            self = min;
1586        }
1587        if self > max {
1588            self = max;
1589        }
1590        self
1591    }
1592
1593    /// Clamps this number to a symmetric range centered around zero.
1594    ///
1595    /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
1596    ///
1597    /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
1598    /// explicit about the intent.
1599    ///
1600    /// # Panics
1601    ///
1602    /// Panics if `limit` is negative or NaN, as this indicates a logic error.
1603    ///
1604    /// # Examples
1605    ///
1606    /// ```
1607    /// #![feature(clamp_magnitude)]
1608    /// assert_eq!(5.0f32.clamp_magnitude(3.0), 3.0);
1609    /// assert_eq!((-5.0f32).clamp_magnitude(3.0), -3.0);
1610    /// assert_eq!(2.0f32.clamp_magnitude(3.0), 2.0);
1611    /// assert_eq!((-2.0f32).clamp_magnitude(3.0), -2.0);
1612    /// ```
1613    #[must_use = "this returns the clamped value and does not modify the original"]
1614    #[unstable(feature = "clamp_magnitude", issue = "148519")]
1615    #[inline]
1616    pub fn clamp_magnitude(self, limit: f32) -> f32 {
1617        assert!(limit >= 0.0, "limit must be non-negative");
1618        let limit = limit.abs(); // Canonicalises -0.0 to 0.0
1619        self.clamp(-limit, limit)
1620    }
1621
1622    /// Computes the absolute value of `self`.
1623    ///
1624    /// This function always returns the precise result.
1625    ///
1626    /// # Examples
1627    ///
1628    /// ```
1629    /// let x = 3.5_f32;
1630    /// let y = -3.5_f32;
1631    ///
1632    /// assert_eq!(x.abs(), x);
1633    /// assert_eq!(y.abs(), -y);
1634    ///
1635    /// assert!(f32::NAN.abs().is_nan());
1636    /// ```
1637    #[must_use = "method returns a new number and does not mutate the original value"]
1638    #[stable(feature = "rust1", since = "1.0.0")]
1639    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1640    #[inline]
1641    #[ferrocene::prevalidated]
1642    pub const fn abs(self) -> f32 {
1643        intrinsics::fabs(self)
1644    }
1645
1646    /// Returns a number that represents the sign of `self`.
1647    ///
1648    /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
1649    /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
1650    /// - NaN if the number is NaN
1651    ///
1652    /// # Examples
1653    ///
1654    /// ```
1655    /// let f = 3.5_f32;
1656    ///
1657    /// assert_eq!(f.signum(), 1.0);
1658    /// assert_eq!(f32::NEG_INFINITY.signum(), -1.0);
1659    ///
1660    /// assert!(f32::NAN.signum().is_nan());
1661    /// ```
1662    #[must_use = "method returns a new number and does not mutate the original value"]
1663    #[stable(feature = "rust1", since = "1.0.0")]
1664    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1665    #[inline]
1666    #[ferrocene::prevalidated]
1667    pub const fn signum(self) -> f32 {
1668        if self.is_nan() { Self::NAN } else { 1.0_f32.copysign(self) }
1669    }
1670
1671    /// Returns a number composed of the magnitude of `self` and the sign of
1672    /// `sign`.
1673    ///
1674    /// Equal to `self` if the sign of `self` and `sign` are the same, otherwise equal to `-self`.
1675    /// If `self` is a NaN, then a NaN with the same payload as `self` and the sign bit of `sign` is
1676    /// returned.
1677    ///
1678    /// If `sign` is a NaN, then this operation will still carry over its sign into the result. Note
1679    /// that IEEE 754 doesn't assign any meaning to the sign bit in case of a NaN, and as Rust
1680    /// doesn't guarantee that the bit pattern of NaNs are conserved over arithmetic operations, the
1681    /// result of `copysign` with `sign` being a NaN might produce an unexpected or non-portable
1682    /// result. See the [specification of NaN bit patterns](primitive@f32#nan-bit-patterns) for more
1683    /// info.
1684    ///
1685    /// # Examples
1686    ///
1687    /// ```
1688    /// let f = 3.5_f32;
1689    ///
1690    /// assert_eq!(f.copysign(0.42), 3.5_f32);
1691    /// assert_eq!(f.copysign(-0.42), -3.5_f32);
1692    /// assert_eq!((-f).copysign(0.42), 3.5_f32);
1693    /// assert_eq!((-f).copysign(-0.42), -3.5_f32);
1694    ///
1695    /// assert!(f32::NAN.copysign(1.0).is_nan());
1696    /// ```
1697    #[must_use = "method returns a new number and does not mutate the original value"]
1698    #[inline]
1699    #[stable(feature = "copysign", since = "1.35.0")]
1700    #[rustc_const_stable(feature = "const_float_methods", since = "1.85.0")]
1701    #[ferrocene::prevalidated]
1702    pub const fn copysign(self, sign: f32) -> f32 {
1703        intrinsics::copysignf32(self, sign)
1704    }
1705
1706    /// Float addition that allows optimizations based on algebraic rules.
1707    ///
1708    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1709    #[must_use = "method returns a new number and does not mutate the original value"]
1710    #[unstable(feature = "float_algebraic", issue = "136469")]
1711    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1712    #[inline]
1713    pub const fn algebraic_add(self, rhs: f32) -> f32 {
1714        intrinsics::fadd_algebraic(self, rhs)
1715    }
1716
1717    /// Float subtraction that allows optimizations based on algebraic rules.
1718    ///
1719    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1720    #[must_use = "method returns a new number and does not mutate the original value"]
1721    #[unstable(feature = "float_algebraic", issue = "136469")]
1722    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1723    #[inline]
1724    pub const fn algebraic_sub(self, rhs: f32) -> f32 {
1725        intrinsics::fsub_algebraic(self, rhs)
1726    }
1727
1728    /// Float multiplication that allows optimizations based on algebraic rules.
1729    ///
1730    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1731    #[must_use = "method returns a new number and does not mutate the original value"]
1732    #[unstable(feature = "float_algebraic", issue = "136469")]
1733    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1734    #[inline]
1735    pub const fn algebraic_mul(self, rhs: f32) -> f32 {
1736        intrinsics::fmul_algebraic(self, rhs)
1737    }
1738
1739    /// Float division that allows optimizations based on algebraic rules.
1740    ///
1741    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1742    #[must_use = "method returns a new number and does not mutate the original value"]
1743    #[unstable(feature = "float_algebraic", issue = "136469")]
1744    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1745    #[inline]
1746    pub const fn algebraic_div(self, rhs: f32) -> f32 {
1747        intrinsics::fdiv_algebraic(self, rhs)
1748    }
1749
1750    /// Float remainder that allows optimizations based on algebraic rules.
1751    ///
1752    /// See [algebraic operators](primitive@f32#algebraic-operators) for more info.
1753    #[must_use = "method returns a new number and does not mutate the original value"]
1754    #[unstable(feature = "float_algebraic", issue = "136469")]
1755    #[rustc_const_unstable(feature = "float_algebraic", issue = "136469")]
1756    #[inline]
1757    pub const fn algebraic_rem(self, rhs: f32) -> f32 {
1758        intrinsics::frem_algebraic(self, rhs)
1759    }
1760}
1761
1762/// Experimental implementations of floating point functions in `core`.
1763///
1764/// _The standalone functions in this module are for testing only.
1765/// They will be stabilized as inherent methods._
1766#[unstable(feature = "core_float_math", issue = "137578")]
1767pub mod math {
1768    use crate::intrinsics;
1769    use crate::num::imp::libm;
1770
1771    /// Experimental version of `floor` in `core`. See [`f32::floor`] for details.
1772    ///
1773    /// # Examples
1774    ///
1775    /// ```
1776    /// #![feature(core_float_math)]
1777    ///
1778    /// use core::f32;
1779    ///
1780    /// let f = 3.7_f32;
1781    /// let g = 3.0_f32;
1782    /// let h = -3.7_f32;
1783    ///
1784    /// assert_eq!(f32::math::floor(f), 3.0);
1785    /// assert_eq!(f32::math::floor(g), 3.0);
1786    /// assert_eq!(f32::math::floor(h), -4.0);
1787    /// ```
1788    ///
1789    /// _This standalone function is for testing only.
1790    /// It will be stabilized as an inherent method._
1791    ///
1792    /// [`f32::floor`]: ../../../std/primitive.f32.html#method.floor
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 floor(x: f32) -> f32 {
1797        intrinsics::floorf32(x)
1798    }
1799
1800    /// Experimental version of `ceil` in `core`. See [`f32::ceil`] for details.
1801    ///
1802    /// # Examples
1803    ///
1804    /// ```
1805    /// #![feature(core_float_math)]
1806    ///
1807    /// use core::f32;
1808    ///
1809    /// let f = 3.01_f32;
1810    /// let g = 4.0_f32;
1811    ///
1812    /// assert_eq!(f32::math::ceil(f), 4.0);
1813    /// assert_eq!(f32::math::ceil(g), 4.0);
1814    /// ```
1815    ///
1816    /// _This standalone function is for testing only.
1817    /// It will be stabilized as an inherent method._
1818    ///
1819    /// [`f32::ceil`]: ../../../std/primitive.f32.html#method.ceil
1820    #[inline]
1821    #[doc(alias = "ceiling")]
1822    #[must_use = "method returns a new number and does not mutate the original value"]
1823    #[unstable(feature = "core_float_math", issue = "137578")]
1824    pub const fn ceil(x: f32) -> f32 {
1825        intrinsics::ceilf32(x)
1826    }
1827
1828    /// Experimental version of `round` in `core`. See [`f32::round`] for details.
1829    ///
1830    /// # Examples
1831    ///
1832    /// ```
1833    /// #![feature(core_float_math)]
1834    ///
1835    /// use core::f32;
1836    ///
1837    /// let f = 3.3_f32;
1838    /// let g = -3.3_f32;
1839    /// let h = -3.7_f32;
1840    /// let i = 3.5_f32;
1841    /// let j = 4.5_f32;
1842    ///
1843    /// assert_eq!(f32::math::round(f), 3.0);
1844    /// assert_eq!(f32::math::round(g), -3.0);
1845    /// assert_eq!(f32::math::round(h), -4.0);
1846    /// assert_eq!(f32::math::round(i), 4.0);
1847    /// assert_eq!(f32::math::round(j), 5.0);
1848    /// ```
1849    ///
1850    /// _This standalone function is for testing only.
1851    /// It will be stabilized as an inherent method._
1852    ///
1853    /// [`f32::round`]: ../../../std/primitive.f32.html#method.round
1854    #[inline]
1855    #[unstable(feature = "core_float_math", issue = "137578")]
1856    #[must_use = "method returns a new number and does not mutate the original value"]
1857    pub const fn round(x: f32) -> f32 {
1858        intrinsics::roundf32(x)
1859    }
1860
1861    /// Experimental version of `round_ties_even` in `core`. See [`f32::round_ties_even`] for
1862    /// details.
1863    ///
1864    /// # Examples
1865    ///
1866    /// ```
1867    /// #![feature(core_float_math)]
1868    ///
1869    /// use core::f32;
1870    ///
1871    /// let f = 3.3_f32;
1872    /// let g = -3.3_f32;
1873    /// let h = 3.5_f32;
1874    /// let i = 4.5_f32;
1875    ///
1876    /// assert_eq!(f32::math::round_ties_even(f), 3.0);
1877    /// assert_eq!(f32::math::round_ties_even(g), -3.0);
1878    /// assert_eq!(f32::math::round_ties_even(h), 4.0);
1879    /// assert_eq!(f32::math::round_ties_even(i), 4.0);
1880    /// ```
1881    ///
1882    /// _This standalone function is for testing only.
1883    /// It will be stabilized as an inherent method._
1884    ///
1885    /// [`f32::round_ties_even`]: ../../../std/primitive.f32.html#method.round_ties_even
1886    #[inline]
1887    #[unstable(feature = "core_float_math", issue = "137578")]
1888    #[must_use = "method returns a new number and does not mutate the original value"]
1889    pub const fn round_ties_even(x: f32) -> f32 {
1890        intrinsics::round_ties_even_f32(x)
1891    }
1892
1893    /// Experimental version of `trunc` in `core`. See [`f32::trunc`] for details.
1894    ///
1895    /// # Examples
1896    ///
1897    /// ```
1898    /// #![feature(core_float_math)]
1899    ///
1900    /// use core::f32;
1901    ///
1902    /// let f = 3.7_f32;
1903    /// let g = 3.0_f32;
1904    /// let h = -3.7_f32;
1905    ///
1906    /// assert_eq!(f32::math::trunc(f), 3.0);
1907    /// assert_eq!(f32::math::trunc(g), 3.0);
1908    /// assert_eq!(f32::math::trunc(h), -3.0);
1909    /// ```
1910    ///
1911    /// _This standalone function is for testing only.
1912    /// It will be stabilized as an inherent method._
1913    ///
1914    /// [`f32::trunc`]: ../../../std/primitive.f32.html#method.trunc
1915    #[inline]
1916    #[doc(alias = "truncate")]
1917    #[must_use = "method returns a new number and does not mutate the original value"]
1918    #[unstable(feature = "core_float_math", issue = "137578")]
1919    pub const fn trunc(x: f32) -> f32 {
1920        intrinsics::truncf32(x)
1921    }
1922
1923    /// Experimental version of `fract` in `core`. See [`f32::fract`] for details.
1924    ///
1925    /// # Examples
1926    ///
1927    /// ```
1928    /// #![feature(core_float_math)]
1929    ///
1930    /// use core::f32;
1931    ///
1932    /// let x = 3.6_f32;
1933    /// let y = -3.6_f32;
1934    /// let abs_difference_x = (f32::math::fract(x) - 0.6).abs();
1935    /// let abs_difference_y = (f32::math::fract(y) - (-0.6)).abs();
1936    ///
1937    /// assert!(abs_difference_x <= f32::EPSILON);
1938    /// assert!(abs_difference_y <= f32::EPSILON);
1939    /// ```
1940    ///
1941    /// _This standalone function is for testing only.
1942    /// It will be stabilized as an inherent method._
1943    ///
1944    /// [`f32::fract`]: ../../../std/primitive.f32.html#method.fract
1945    #[inline]
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 const fn fract(x: f32) -> f32 {
1949        x - trunc(x)
1950    }
1951
1952    /// Experimental version of `mul_add` in `core`. See [`f32::mul_add`] for details.
1953    ///
1954    /// # Examples
1955    ///
1956    /// ```
1957    /// # #![allow(unused_features)]
1958    /// #![feature(core_float_math)]
1959    ///
1960    /// # // FIXME(#140515): mingw has an incorrect fma
1961    /// # // https://sourceforge.net/p/mingw-w64/bugs/848/
1962    /// # #[cfg(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")))] {
1963    /// use core::f32;
1964    ///
1965    /// let m = 10.0_f32;
1966    /// let x = 4.0_f32;
1967    /// let b = 60.0_f32;
1968    ///
1969    /// assert_eq!(f32::math::mul_add(m, x, b), 100.0);
1970    /// assert_eq!(m * x + b, 100.0);
1971    ///
1972    /// let one_plus_eps = 1.0_f32 + f32::EPSILON;
1973    /// let one_minus_eps = 1.0_f32 - f32::EPSILON;
1974    /// let minus_one = -1.0_f32;
1975    ///
1976    /// // The exact result (1 + eps) * (1 - eps) = 1 - eps * eps.
1977    /// assert_eq!(
1978    ///     f32::math::mul_add(one_plus_eps, one_minus_eps, minus_one),
1979    ///     -f32::EPSILON * f32::EPSILON
1980    /// );
1981    /// // Different rounding with the non-fused multiply and add.
1982    /// assert_eq!(one_plus_eps * one_minus_eps + minus_one, 0.0);
1983    /// # }
1984    /// ```
1985    ///
1986    /// _This standalone function is for testing only.
1987    /// It will be stabilized as an inherent method._
1988    ///
1989    /// [`f32::mul_add`]: ../../../std/primitive.f32.html#method.mul_add
1990    #[inline]
1991    #[doc(alias = "fmaf", alias = "fusedMultiplyAdd")]
1992    #[must_use = "method returns a new number and does not mutate the original value"]
1993    #[unstable(feature = "core_float_math", issue = "137578")]
1994    pub const fn mul_add(x: f32, y: f32, z: f32) -> f32 {
1995        intrinsics::fmaf32(x, y, z)
1996    }
1997
1998    /// Experimental version of `div_euclid` in `core`. See [`f32::div_euclid`] for details.
1999    ///
2000    /// # Examples
2001    ///
2002    /// ```
2003    /// #![feature(core_float_math)]
2004    ///
2005    /// use core::f32;
2006    ///
2007    /// let a: f32 = 7.0;
2008    /// let b = 4.0;
2009    /// assert_eq!(f32::math::div_euclid(a, b), 1.0); // 7.0 > 4.0 * 1.0
2010    /// assert_eq!(f32::math::div_euclid(-a, b), -2.0); // -7.0 >= 4.0 * -2.0
2011    /// assert_eq!(f32::math::div_euclid(a, -b), -1.0); // 7.0 >= -4.0 * -1.0
2012    /// assert_eq!(f32::math::div_euclid(-a, -b), 2.0); // -7.0 >= -4.0 * 2.0
2013    /// ```
2014    ///
2015    /// _This standalone function is for testing only.
2016    /// It will be stabilized as an inherent method._
2017    ///
2018    /// [`f32::div_euclid`]: ../../../std/primitive.f32.html#method.div_euclid
2019    #[inline]
2020    #[unstable(feature = "core_float_math", issue = "137578")]
2021    #[must_use = "method returns a new number and does not mutate the original value"]
2022    pub fn div_euclid(x: f32, rhs: f32) -> f32 {
2023        let q = trunc(x / rhs);
2024        if x % rhs < 0.0 {
2025            return if rhs > 0.0 { q - 1.0 } else { q + 1.0 };
2026        }
2027        q
2028    }
2029
2030    /// Experimental version of `rem_euclid` in `core`. See [`f32::rem_euclid`] for details.
2031    ///
2032    /// # Examples
2033    ///
2034    /// ```
2035    /// #![feature(core_float_math)]
2036    ///
2037    /// use core::f32;
2038    ///
2039    /// let a: f32 = 7.0;
2040    /// let b = 4.0;
2041    /// assert_eq!(f32::math::rem_euclid(a, b), 3.0);
2042    /// assert_eq!(f32::math::rem_euclid(-a, b), 1.0);
2043    /// assert_eq!(f32::math::rem_euclid(a, -b), 3.0);
2044    /// assert_eq!(f32::math::rem_euclid(-a, -b), 1.0);
2045    /// // limitation due to round-off error
2046    /// assert!(f32::math::rem_euclid(-f32::EPSILON, 3.0) != 0.0);
2047    /// ```
2048    ///
2049    /// _This standalone function is for testing only.
2050    /// It will be stabilized as an inherent method._
2051    ///
2052    /// [`f32::rem_euclid`]: ../../../std/primitive.f32.html#method.rem_euclid
2053    #[inline]
2054    #[doc(alias = "modulo", alias = "mod")]
2055    #[unstable(feature = "core_float_math", issue = "137578")]
2056    #[must_use = "method returns a new number and does not mutate the original value"]
2057    pub fn rem_euclid(x: f32, rhs: f32) -> f32 {
2058        let r = x % rhs;
2059        if r < 0.0 { r + rhs.abs() } else { r }
2060    }
2061
2062    /// Experimental version of `powi` in `core`. See [`f32::powi`] for details.
2063    ///
2064    /// # Examples
2065    ///
2066    /// ```
2067    /// #![feature(core_float_math)]
2068    ///
2069    /// use core::f32;
2070    ///
2071    /// let x = 2.0_f32;
2072    /// let abs_difference = (f32::math::powi(x, 2) - (x * x)).abs();
2073    /// assert!(abs_difference <= 1e-5);
2074    ///
2075    /// assert_eq!(f32::math::powi(f32::NAN, 0), 1.0);
2076    /// ```
2077    ///
2078    /// _This standalone function is for testing only.
2079    /// It will be stabilized as an inherent method._
2080    ///
2081    /// [`f32::powi`]: ../../../std/primitive.f32.html#method.powi
2082    #[inline]
2083    #[must_use = "method returns a new number and does not mutate the original value"]
2084    #[unstable(feature = "core_float_math", issue = "137578")]
2085    pub fn powi(x: f32, n: i32) -> f32 {
2086        intrinsics::powif32(x, n)
2087    }
2088
2089    /// Experimental version of `sqrt` in `core`. See [`f32::sqrt`] for details.
2090    ///
2091    /// # Examples
2092    ///
2093    /// ```
2094    /// #![feature(core_float_math)]
2095    ///
2096    /// use core::f32;
2097    ///
2098    /// let positive = 4.0_f32;
2099    /// let negative = -4.0_f32;
2100    /// let negative_zero = -0.0_f32;
2101    ///
2102    /// assert_eq!(f32::math::sqrt(positive), 2.0);
2103    /// assert!(f32::math::sqrt(negative).is_nan());
2104    /// assert_eq!(f32::math::sqrt(negative_zero), negative_zero);
2105    /// ```
2106    ///
2107    /// _This standalone function is for testing only.
2108    /// It will be stabilized as an inherent method._
2109    ///
2110    /// [`f32::sqrt`]: ../../../std/primitive.f32.html#method.sqrt
2111    #[inline]
2112    #[doc(alias = "squareRoot")]
2113    #[unstable(feature = "core_float_math", issue = "137578")]
2114    #[must_use = "method returns a new number and does not mutate the original value"]
2115    pub fn sqrt(x: f32) -> f32 {
2116        intrinsics::sqrtf32(x)
2117    }
2118
2119    /// Experimental version of `abs_sub` in `core`. See [`f32::abs_sub`] for details.
2120    ///
2121    /// # Examples
2122    ///
2123    /// ```
2124    /// #![feature(core_float_math)]
2125    ///
2126    /// use core::f32;
2127    ///
2128    /// let x = 3.0f32;
2129    /// let y = -3.0f32;
2130    ///
2131    /// let abs_difference_x = (f32::math::abs_sub(x, 1.0) - 2.0).abs();
2132    /// let abs_difference_y = (f32::math::abs_sub(y, 1.0) - 0.0).abs();
2133    ///
2134    /// assert!(abs_difference_x <= 1e-6);
2135    /// assert!(abs_difference_y <= 1e-6);
2136    /// ```
2137    ///
2138    /// _This standalone function is for testing only.
2139    /// It will be stabilized as an inherent method._
2140    ///
2141    /// [`f32::abs_sub`]: ../../../std/primitive.f32.html#method.abs_sub
2142    #[inline]
2143    #[stable(feature = "rust1", since = "1.0.0")]
2144    #[deprecated(
2145        since = "1.10.0",
2146        note = "you probably meant `(self - other).abs()`: \
2147            this operation is `(self - other).max(0.0)` \
2148            except that `abs_sub` also propagates NaNs (also \
2149            known as `fdimf` in C). If you truly need the positive \
2150            difference, consider using that expression or the C function \
2151            `fdimf`, depending on how you wish to handle NaN (please consider \
2152            filing an issue describing your use-case too)."
2153    )]
2154    #[must_use = "method returns a new number and does not mutate the original value"]
2155    pub fn abs_sub(x: f32, other: f32) -> f32 {
2156        libm::fdimf(x, other)
2157    }
2158
2159    /// Experimental version of `cbrt` in `core`. See [`f32::cbrt`] for details.
2160    ///
2161    /// # Unspecified precision
2162    ///
2163    /// The precision of this function is non-deterministic. This means it varies by platform, Rust version, and
2164    /// can even differ within the same execution from one invocation to the next.
2165    /// This function currently corresponds to the `cbrtf` from libc on Unix
2166    /// and Windows. Note that this might change in the future.
2167    ///
2168    /// # Examples
2169    ///
2170    /// ```
2171    /// #![feature(core_float_math)]
2172    ///
2173    /// use core::f32;
2174    ///
2175    /// let x = 8.0f32;
2176    ///
2177    /// // x^(1/3) - 2 == 0
2178    /// let abs_difference = (f32::math::cbrt(x) - 2.0).abs();
2179    ///
2180    /// assert!(abs_difference <= 1e-6);
2181    /// ```
2182    ///
2183    /// _This standalone function is for testing only.
2184    /// It will be stabilized as an inherent method._
2185    ///
2186    /// [`f32::cbrt`]: ../../../std/primitive.f32.html#method.cbrt
2187    #[inline]
2188    #[must_use = "method returns a new number and does not mutate the original value"]
2189    #[unstable(feature = "core_float_math", issue = "137578")]
2190    pub fn cbrt(x: f32) -> f32 {
2191        libm::cbrtf(x)
2192    }
2193}