diff --git a/library/core/src/num/f128.rs b/library/core/src/num/f128.rs index 129f62fb43d1a..58ed98c888cc6 100644 --- a/library/core/src/num/f128.rs +++ b/library/core/src/num/f128.rs @@ -11,6 +11,7 @@ #![unstable(feature = "f128", issue = "116909")] +use crate::convert::FloatToInt; use crate::mem; /// Basic mathematical constants. @@ -220,21 +221,145 @@ impl f128 { #[unstable(feature = "f128", issue = "116909")] pub const MAX_10_EXP: i32 = 4_932; + /// Not a Number (NaN). + /// + /// Note that IEEE 754 doesn't define just a single NaN value; + /// a plethora of bit patterns are considered to be NaN. + /// Furthermore, the standard makes a difference + /// between a "signaling" and a "quiet" NaN, + /// and allows inspecting its "payload" (the unspecified bits in the bit pattern). + /// This constant isn't guaranteed to equal to any specific NaN bitpattern, + /// and the stability of its representation over Rust versions + /// and target platforms isn't guaranteed. + #[cfg(not(bootstrap))] + #[allow(clippy::eq_op)] + #[rustc_diagnostic_item = "f128_nan"] + #[unstable(feature = "f128", issue = "116909")] + pub const NAN: f128 = 0.0_f128 / 0.0_f128; + + /// Infinity (∞). + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + pub const INFINITY: f128 = 1.0_f128 / 0.0_f128; + + /// Negative infinity (−∞). + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + pub const NEG_INFINITY: f128 = -1.0_f128 / 0.0_f128; + + /// Sign bit + #[cfg(not(bootstrap))] + pub(crate) const SIGN_MASK: u128 = 0x8000_0000_0000_0000_0000_0000_0000_0000; + + /// Minimum representable positive value (min subnormal) + #[cfg(not(bootstrap))] + const TINY_BITS: u128 = 0x1; + + /// Minimum representable negative value (min negative subnormal) + #[cfg(not(bootstrap))] + const NEG_TINY_BITS: u128 = Self::TINY_BITS | Self::SIGN_MASK; + /// Returns `true` if this value is NaN. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `unordtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let nan = f128::NAN; + /// let f = 7.0_f128; + /// + /// assert!(nan.is_nan()); + /// assert!(!f.is_nan()); + /// # } + /// ``` #[inline] #[must_use] + #[cfg(not(bootstrap))] #[unstable(feature = "f128", issue = "116909")] #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :) pub const fn is_nan(self) -> bool { self != self } + // FIXME(#50145): `abs` is publicly unavailable in core due to + // concerns about portability, so this implementation is for + // private use internally. + #[inline] + #[cfg(not(bootstrap))] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub(crate) const fn abs_private(self) -> f128 { + // SAFETY: This transmutation is fine. Probably. For the reasons std is using it. + unsafe { + mem::transmute::(mem::transmute::(self) & !Self::SIGN_MASK) + } + } + + /// Returns `true` if this value is positive infinity or negative infinity, and + /// `false` otherwise. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let f = 7.0f128; + /// let inf = f128::INFINITY; + /// let neg_inf = f128::NEG_INFINITY; + /// let nan = f128::NAN; + /// + /// assert!(!f.is_infinite()); + /// assert!(!nan.is_infinite()); + /// + /// assert!(inf.is_infinite()); + /// assert!(neg_inf.is_infinite()); + /// # } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub const fn is_infinite(self) -> bool { + (self == f128::INFINITY) | (self == f128::NEG_INFINITY) + } + + /// Returns `true` if this number is neither infinite nor NaN. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `lttf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let f = 7.0f128; + /// let inf: f128 = f128::INFINITY; + /// let neg_inf: f128 = f128::NEG_INFINITY; + /// let nan: f128 = f128::NAN; + /// + /// assert!(f.is_finite()); + /// + /// assert!(!nan.is_finite()); + /// assert!(!inf.is_finite()); + /// assert!(!neg_inf.is_finite()); + /// # } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub const fn is_finite(self) -> bool { + // There's no need to handle NaN separately: if self is NaN, + // the comparison is not true, exactly as desired. + self.abs_private() < Self::INFINITY + } + /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with /// positive sign bit and positive infinity. Note that IEEE 754 doesn't assign any /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that /// the bit pattern of NaNs are conserved over arithmetic operations, the result of /// `is_sign_positive` on a NaN might produce an unexpected result in some cases. - /// See [explanation of NaN as a special value](f32) for more info. + /// See [explanation of NaN as a special value](f128) for more info. /// /// ``` /// #![feature(f128)] @@ -257,7 +382,7 @@ impl f128 { /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that /// the bit pattern of NaNs are conserved over arithmetic operations, the result of /// `is_sign_negative` on a NaN might produce an unexpected result in some cases. - /// See [explanation of NaN as a special value](f32) for more info. + /// See [explanation of NaN as a special value](f128) for more info. /// /// ``` /// #![feature(f128)] @@ -278,6 +403,222 @@ impl f128 { (self.to_bits() & (1 << 127)) != 0 } + /// Returns the least number greater than `self`. + /// + /// Let `TINY` be the smallest representable positive `f128`. Then, + /// - if `self.is_nan()`, this returns `self`; + /// - if `self` is [`NEG_INFINITY`], this returns [`MIN`]; + /// - if `self` is `-TINY`, this returns -0.0; + /// - if `self` is -0.0 or +0.0, this returns `TINY`; + /// - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`]; + /// - otherwise the unique least value greater than `self` is returned. + /// + /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x` + /// is finite `x == x.next_up().next_down()` also holds. + /// + /// ```rust + /// #![feature(f128)] + /// #![feature(float_next_up_down)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// // f128::EPSILON is the difference between 1.0 and the next number up. + /// assert_eq!(1.0f128.next_up(), 1.0 + f128::EPSILON); + /// // But not for most numbers. + /// assert!(0.1f128.next_up() < 0.1 + f128::EPSILON); + /// assert_eq!(4611686018427387904f128.next_up(), 4611686018427387904.000000000000001); + /// # } + /// ``` + /// + /// [`NEG_INFINITY`]: Self::NEG_INFINITY + /// [`INFINITY`]: Self::INFINITY + /// [`MIN`]: Self::MIN + /// [`MAX`]: Self::MAX + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + // #[unstable(feature = "float_next_up_down", issue = "91399")] + pub fn next_up(self) -> Self { + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. + let bits = self.to_bits(); + if self.is_nan() || bits == Self::INFINITY.to_bits() { + return self; + } + + let abs = bits & !Self::SIGN_MASK; + let next_bits = if abs == 0 { + Self::TINY_BITS + } else if bits == abs { + bits + 1 + } else { + bits - 1 + }; + Self::from_bits(next_bits) + } + + /// Returns the greatest number less than `self`. + /// + /// Let `TINY` be the smallest representable positive `f128`. Then, + /// - if `self.is_nan()`, this returns `self`; + /// - if `self` is [`INFINITY`], this returns [`MAX`]; + /// - if `self` is `TINY`, this returns 0.0; + /// - if `self` is -0.0 or +0.0, this returns `-TINY`; + /// - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`]; + /// - otherwise the unique greatest value less than `self` is returned. + /// + /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x` + /// is finite `x == x.next_down().next_up()` also holds. + /// + /// ```rust + /// #![feature(f128)] + /// #![feature(float_next_up_down)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let x = 1.0f128; + /// // Clamp value into range [0, 1). + /// let clamped = x.clamp(0.0, 1.0f128.next_down()); + /// assert!(clamped < 1.0); + /// assert_eq!(clamped.next_up(), 1.0); + /// # } + /// ``` + /// + /// [`NEG_INFINITY`]: Self::NEG_INFINITY + /// [`INFINITY`]: Self::INFINITY + /// [`MIN`]: Self::MIN + /// [`MAX`]: Self::MAX + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + // #[unstable(feature = "float_next_up_down", issue = "91399")] + pub fn next_down(self) -> Self { + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. + let bits = self.to_bits(); + if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() { + return self; + } + + let abs = bits & !Self::SIGN_MASK; + let next_bits = if abs == 0 { + Self::NEG_TINY_BITS + } else if bits == abs { + bits - 1 + } else { + bits + 1 + }; + Self::from_bits(next_bits) + } + + /// Takes the reciprocal (inverse) of a number, `1/x`. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let x = 2.0_f128; + /// let abs_difference = (x.recip() - (1.0 / x)).abs(); + /// + /// assert!(abs_difference <= f128::EPSILON); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn recip(self) -> Self { + 1.0 / self + } + + /// Converts radians to degrees. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let angle = std::f128::consts::PI; + /// + /// let abs_difference = (angle.to_degrees() - 180.0).abs(); + /// assert!(abs_difference <= f128::EPSILON); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_degrees(self) -> Self { + // Use a literal for better precision. + const PIS_IN_180: f128 = 57.2957795130823208767981548141051703324054724665643215491602_f128; + self * PIS_IN_180 + } + + /// Converts degrees to radians. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let angle = 180.0f128; + /// + /// let abs_difference = (angle.to_radians() - std::f128::consts::PI).abs(); + /// + /// assert!(abs_difference <= 1e-30); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_radians(self) -> f128 { + // Use a literal for better precision. + const RADS_PER_DEG: f128 = + 0.0174532925199432957692369076848861271344287188854172545609719_f128; + self * RADS_PER_DEG + } + + /// Rounds toward zero and converts to any primitive integer type, + /// assuming that the value is finite and fits in that type. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `float*itf` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let value = 4.6_f128; + /// let rounded = unsafe { value.to_int_unchecked::() }; + /// assert_eq!(rounded, 4); + /// + /// let value = -128.9_f128; + /// let rounded = unsafe { value.to_int_unchecked::() }; + /// assert_eq!(rounded, i8::MIN); + /// # } + /// ``` + /// + /// # Safety + /// + /// The value must: + /// + /// * Not be `NaN` + /// * Not be infinite + /// * Be representable in the return type `Int`, after truncating off its fractional part + #[inline] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub unsafe fn to_int_unchecked(self) -> Int + where + Self: FloatToInt, + { + // SAFETY: the caller must uphold the safety contract for + // `FloatToInt::to_int_unchecked`. + unsafe { FloatToInt::::to_int_unchecked(self) } + } + /// Raw transmutation to `u128`. /// /// This is currently identical to `transmute::(self)` on all platforms. @@ -287,6 +628,14 @@ impl f128 { /// /// Note that this function is distinct from `as` casting, which attempts to /// preserve the *numeric* value, and not the bitwise value. + /// + /// ``` + /// #![feature(f128)] + /// + /// # // FIXME(f16_f128): enable this once const casting works + /// # // assert_ne!((1f128).to_bits(), 1f128 as u128); // to_bits() is not casting! + /// assert_eq!((12.5f128).to_bits(), 0x40029000000000000000000000000000); + /// ``` #[inline] #[unstable(feature = "f128", issue = "116909")] #[must_use = "this returns the result of the operation, without modifying the original"] @@ -326,6 +675,16 @@ impl f128 { /// /// Note that this function is distinct from `as` casting, which attempts to /// preserve the *numeric* value, and not the bitwise value. + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let v = f128::from_bits(0x40029000000000000000000000000000); + /// assert_eq!(v, 12.5); + /// # } + /// ``` #[inline] #[must_use] #[unstable(feature = "f128", issue = "116909")] @@ -335,4 +694,315 @@ impl f128 { // Stability concerns. unsafe { mem::transmute(v) } } + + /// Return the memory representation of this floating point number as a byte array in + /// big-endian (network) byte order. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// + /// let bytes = 12.5f128.to_be_bytes(); + /// assert_eq!( + /// bytes, + /// [0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] + /// ); + /// ``` + #[inline] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_be_bytes(self) -> [u8; 16] { + self.to_bits().to_be_bytes() + } + + /// Return the memory representation of this floating point number as a byte array in + /// little-endian byte order. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// + /// let bytes = 12.5f128.to_le_bytes(); + /// assert_eq!( + /// bytes, + /// [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40] + /// ); + /// ``` + #[inline] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_le_bytes(self) -> [u8; 16] { + self.to_bits().to_le_bytes() + } + + /// Return the memory representation of this floating point number as a byte array in + /// native byte order. + /// + /// As the target platform's native endianness is used, portable code + /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead. + /// + /// [`to_be_bytes`]: f128::to_be_bytes + /// [`to_le_bytes`]: f128::to_le_bytes + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// + /// let bytes = 12.5f128.to_ne_bytes(); + /// assert_eq!( + /// bytes, + /// if cfg!(target_endian = "big") { + /// [0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] + /// } else { + /// [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40] + /// } + /// ); + /// ``` + #[inline] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_ne_bytes(self) -> [u8; 16] { + self.to_bits().to_ne_bytes() + } + + /// Create a floating point value from its representation as a byte array in big endian. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let value = f128::from_be_bytes( + /// [0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] + /// ); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f128", issue = "116909")] + pub fn from_be_bytes(bytes: [u8; 16]) -> Self { + Self::from_bits(u128::from_be_bytes(bytes)) + } + + /// Create a floating point value from its representation as a byte array in little endian. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let value = f128::from_le_bytes( + /// [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40] + /// ); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f128", issue = "116909")] + pub fn from_le_bytes(bytes: [u8; 16]) -> Self { + Self::from_bits(u128::from_le_bytes(bytes)) + } + + /// Create a floating point value from its representation as a byte array in native endian. + /// + /// As the target platform's native endianness is used, portable code + /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as + /// appropriate instead. + /// + /// [`from_be_bytes`]: f128::from_be_bytes + /// [`from_le_bytes`]: f128::from_le_bytes + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `eqtf2` is available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let value = f128::from_ne_bytes(if cfg!(target_endian = "big") { + /// [0x40, 0x02, 0x90, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00] + /// } else { + /// [0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + /// 0x00, 0x00, 0x00, 0x00, 0x00, 0x90, 0x02, 0x40] + /// }); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f128", issue = "116909")] + pub fn from_ne_bytes(bytes: [u8; 16]) -> Self { + Self::from_bits(u128::from_ne_bytes(bytes)) + } + + /// Return the ordering between `self` and `other`. + /// + /// Unlike the standard partial comparison between floating point numbers, + /// this comparison always produces an ordering in accordance to + /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision) + /// floating point standard. The values are ordered in the following sequence: + /// + /// - negative quiet NaN + /// - negative signaling NaN + /// - negative infinity + /// - negative numbers + /// - negative subnormal numbers + /// - negative zero + /// - positive zero + /// - positive subnormal numbers + /// - positive numbers + /// - positive infinity + /// - positive signaling NaN + /// - positive quiet NaN. + /// + /// The ordering established by this function does not always agree with the + /// [`PartialOrd`] and [`PartialEq`] implementations of `f128`. For example, + /// they consider negative and positive zero equal, while `total_cmp` + /// doesn't. + /// + /// The interpretation of the signaling NaN bit follows the definition in + /// the IEEE 754 standard, which may not match the interpretation by some of + /// the older, non-conformant (e.g. MIPS) hardware implementations. + /// + /// # Example + /// + /// ``` + /// #![feature(f128)] + /// + /// struct GoodBoy { + /// name: &'static str, + /// weight: f128, + /// } + /// + /// let mut bois = vec![ + /// GoodBoy { name: "Pucci", weight: 0.1 }, + /// GoodBoy { name: "Woofer", weight: 99.0 }, + /// GoodBoy { name: "Yapper", weight: 10.0 }, + /// GoodBoy { name: "Chonk", weight: f128::INFINITY }, + /// GoodBoy { name: "Abs. Unit", weight: f128::NAN }, + /// GoodBoy { name: "Floaty", weight: -5.0 }, + /// ]; + /// + /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight)); + /// + /// // `f128::NAN` could be positive or negative, which will affect the sort order. + /// if f128::NAN.is_sign_negative() { + /// bois.into_iter().map(|b| b.weight) + /// .zip([f128::NAN, -5.0, 0.1, 10.0, 99.0, f128::INFINITY].iter()) + /// .for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits())) + /// } else { + /// bois.into_iter().map(|b| b.weight) + /// .zip([-5.0, 0.1, 10.0, 99.0, f128::INFINITY, f128::NAN].iter()) + /// .for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits())) + /// } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + pub fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering { + let mut left = self.to_bits() as i128; + let mut right = other.to_bits() as i128; + + // In case of negatives, flip all the bits except the sign + // to achieve a similar layout as two's complement integers + // + // Why does this work? IEEE 754 floats consist of three fields: + // Sign bit, exponent and mantissa. The set of exponent and mantissa + // fields as a whole have the property that their bitwise order is + // equal to the numeric magnitude where the magnitude is defined. + // The magnitude is not normally defined on NaN values, but + // IEEE 754 totalOrder defines the NaN values also to follow the + // bitwise order. This leads to order explained in the doc comment. + // However, the representation of magnitude is the same for negative + // and positive numbers – only the sign bit is different. + // To easily compare the floats as signed integers, we need to + // flip the exponent and mantissa bits in case of negative numbers. + // We effectively convert the numbers to "two's complement" form. + // + // To do the flipping, we construct a mask and XOR against it. + // We branchlessly calculate an "all-ones except for the sign bit" + // mask from negative-signed values: right shifting sign-extends + // the integer, so we "fill" the mask with sign bits, and then + // convert to unsigned to push one more zero bit. + // On positive values, the mask is all zeros, so it's a no-op. + left ^= (((left >> 127) as u128) >> 1) as i128; + right ^= (((right >> 127) as u128) >> 1) as i128; + + left.cmp(&right) + } + + /// Restrict a value to a certain interval unless it is NaN. + /// + /// Returns `max` if `self` is greater than `max`, and `min` if `self` is + /// less than `min`. Otherwise this returns `self`. + /// + /// Note that this function returns NaN if the initial value was NaN as + /// well. + /// + /// # Panics + /// + /// Panics if `min > max`, `min` is NaN, or `max` is NaN. + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// # // FIXME(f16_f128): remove when `{eq,gt,unord}tf` are available + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// assert!((-3.0f128).clamp(-2.0, 1.0) == -2.0); + /// assert!((0.0f128).clamp(-2.0, 1.0) == 0.0); + /// assert!((2.0f128).clamp(-2.0, 1.0) == 1.0); + /// assert!((f128::NAN).clamp(-2.0, 1.0).is_nan()); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "method returns a new number and does not mutate the original value"] + pub fn clamp(mut self, min: f128, max: f128) -> f128 { + assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}"); + if self < min { + self = min; + } + if self > max { + self = max; + } + self + } } diff --git a/library/core/src/num/f16.rs b/library/core/src/num/f16.rs index 7a488cd6bf6fa..3c58b0af9c27e 100644 --- a/library/core/src/num/f16.rs +++ b/library/core/src/num/f16.rs @@ -11,6 +11,7 @@ #![unstable(feature = "f16", issue = "116909")] +use crate::convert::FloatToInt; use crate::mem; /// Basic mathematical constants. @@ -215,21 +216,140 @@ impl f16 { #[unstable(feature = "f16", issue = "116909")] pub const MAX_10_EXP: i32 = 4; + /// Not a Number (NaN). + /// + /// Note that IEEE 754 doesn't define just a single NaN value; + /// a plethora of bit patterns are considered to be NaN. + /// Furthermore, the standard makes a difference + /// between a "signaling" and a "quiet" NaN, + /// and allows inspecting its "payload" (the unspecified bits in the bit pattern). + /// This constant isn't guaranteed to equal to any specific NaN bitpattern, + /// and the stability of its representation over Rust versions + /// and target platforms isn't guaranteed. + #[cfg(not(bootstrap))] + #[allow(clippy::eq_op)] + #[rustc_diagnostic_item = "f16_nan"] + #[unstable(feature = "f16", issue = "116909")] + pub const NAN: f16 = 0.0_f16 / 0.0_f16; + + /// Infinity (∞). + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + pub const INFINITY: f16 = 1.0_f16 / 0.0_f16; + + /// Negative infinity (−∞). + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + pub const NEG_INFINITY: f16 = -1.0_f16 / 0.0_f16; + + /// Sign bit + #[cfg(not(bootstrap))] + const SIGN_MASK: u16 = 0x8000; + + /// Minimum representable positive value (min subnormal) + #[cfg(not(bootstrap))] + const TINY_BITS: u16 = 0x1; + + /// Minimum representable negative value (min negative subnormal) + #[cfg(not(bootstrap))] + const NEG_TINY_BITS: u16 = Self::TINY_BITS | Self::SIGN_MASK; + /// Returns `true` if this value is NaN. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let nan = f16::NAN; + /// let f = 7.0_f16; + /// + /// assert!(nan.is_nan()); + /// assert!(!f.is_nan()); + /// # } + /// ``` #[inline] #[must_use] + #[cfg(not(bootstrap))] #[unstable(feature = "f16", issue = "116909")] #[allow(clippy::eq_op)] // > if you intended to check if the operand is NaN, use `.is_nan()` instead :) pub const fn is_nan(self) -> bool { self != self } + // FIXMxE(#50145): `abs` is publicly unavailable in core due to + // concerns about portability, so this implementation is for + // private use internally. + #[inline] + #[cfg(not(bootstrap))] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub(crate) const fn abs_private(self) -> f16 { + // SAFETY: This transmutation is fine. Probably. For the reasons std is using it. + unsafe { mem::transmute::(mem::transmute::(self) & !Self::SIGN_MASK) } + } + + /// Returns `true` if this value is positive infinity or negative infinity, and + /// `false` otherwise. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let f = 7.0f16; + /// let inf = f16::INFINITY; + /// let neg_inf = f16::NEG_INFINITY; + /// let nan = f16::NAN; + /// + /// assert!(!f.is_infinite()); + /// assert!(!nan.is_infinite()); + /// + /// assert!(inf.is_infinite()); + /// assert!(neg_inf.is_infinite()); + /// # } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub const fn is_infinite(self) -> bool { + (self == f16::INFINITY) | (self == f16::NEG_INFINITY) + } + + /// Returns `true` if this number is neither infinite nor NaN. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let f = 7.0f16; + /// let inf: f16 = f16::INFINITY; + /// let neg_inf: f16 = f16::NEG_INFINITY; + /// let nan: f16 = f16::NAN; + /// + /// assert!(f.is_finite()); + /// + /// assert!(!nan.is_finite()); + /// assert!(!inf.is_finite()); + /// assert!(!neg_inf.is_finite()); + /// # } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] + pub const fn is_finite(self) -> bool { + // There's no need to handle NaN separately: if self is NaN, + // the comparison is not true, exactly as desired. + self.abs_private() < Self::INFINITY + } + /// Returns `true` if `self` has a positive sign, including `+0.0`, NaNs with /// positive sign bit and positive infinity. Note that IEEE 754 doesn't assign any /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that /// the bit pattern of NaNs are conserved over arithmetic operations, the result of /// `is_sign_positive` on a NaN might produce an unexpected result in some cases. - /// See [explanation of NaN as a special value](f32) for more info. + /// See [explanation of NaN as a special value](f16) for more info. /// /// ``` /// #![feature(f16)] @@ -252,7 +372,7 @@ impl f16 { /// meaning to the sign bit in case of a NaN, and as Rust doesn't guarantee that /// the bit pattern of NaNs are conserved over arithmetic operations, the result of /// `is_sign_negative` on a NaN might produce an unexpected result in some cases. - /// See [explanation of NaN as a special value](f32) for more info. + /// See [explanation of NaN as a special value](f16) for more info. /// /// ``` /// #![feature(f16)] @@ -273,6 +393,220 @@ impl f16 { (self.to_bits() & (1 << 15)) != 0 } + /// Returns the least number greater than `self`. + /// + /// Let `TINY` be the smallest representable positive `f16`. Then, + /// - if `self.is_nan()`, this returns `self`; + /// - if `self` is [`NEG_INFINITY`], this returns [`MIN`]; + /// - if `self` is `-TINY`, this returns -0.0; + /// - if `self` is -0.0 or +0.0, this returns `TINY`; + /// - if `self` is [`MAX`] or [`INFINITY`], this returns [`INFINITY`]; + /// - otherwise the unique least value greater than `self` is returned. + /// + /// The identity `x.next_up() == -(-x).next_down()` holds for all non-NaN `x`. When `x` + /// is finite `x == x.next_up().next_down()` also holds. + /// + /// ```rust + /// #![feature(f16)] + /// #![feature(float_next_up_down)] + /// # // FIXME(f16_f128): ABI issues on MSVC + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// // f16::EPSILON is the difference between 1.0 and the next number up. + /// assert_eq!(1.0f16.next_up(), 1.0 + f16::EPSILON); + /// // But not for most numbers. + /// assert!(0.1f16.next_up() < 0.1 + f16::EPSILON); + /// assert_eq!(4356f16.next_up(), 4360.0); + /// # } + /// ``` + /// + /// [`NEG_INFINITY`]: Self::NEG_INFINITY + /// [`INFINITY`]: Self::INFINITY + /// [`MIN`]: Self::MIN + /// [`MAX`]: Self::MAX + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + // #[unstable(feature = "float_next_up_down", issue = "91399")] + pub fn next_up(self) -> Self { + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. + let bits = self.to_bits(); + if self.is_nan() || bits == Self::INFINITY.to_bits() { + return self; + } + + let abs = bits & !Self::SIGN_MASK; + let next_bits = if abs == 0 { + Self::TINY_BITS + } else if bits == abs { + bits + 1 + } else { + bits - 1 + }; + Self::from_bits(next_bits) + } + + /// Returns the greatest number less than `self`. + /// + /// Let `TINY` be the smallest representable positive `f16`. Then, + /// - if `self.is_nan()`, this returns `self`; + /// - if `self` is [`INFINITY`], this returns [`MAX`]; + /// - if `self` is `TINY`, this returns 0.0; + /// - if `self` is -0.0 or +0.0, this returns `-TINY`; + /// - if `self` is [`MIN`] or [`NEG_INFINITY`], this returns [`NEG_INFINITY`]; + /// - otherwise the unique greatest value less than `self` is returned. + /// + /// The identity `x.next_down() == -(-x).next_up()` holds for all non-NaN `x`. When `x` + /// is finite `x == x.next_down().next_up()` also holds. + /// + /// ```rust + /// #![feature(f16)] + /// #![feature(float_next_up_down)] + /// # // FIXME(f16_f128): ABI issues on MSVC + /// # #[cfg(all(target_arch = "x86_64", target_os = "linux"))] { + /// + /// let x = 1.0f16; + /// // Clamp value into range [0, 1). + /// let clamped = x.clamp(0.0, 1.0f16.next_down()); + /// assert!(clamped < 1.0); + /// assert_eq!(clamped.next_up(), 1.0); + /// # } + /// ``` + /// + /// [`NEG_INFINITY`]: Self::NEG_INFINITY + /// [`INFINITY`]: Self::INFINITY + /// [`MIN`]: Self::MIN + /// [`MAX`]: Self::MAX + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + // #[unstable(feature = "float_next_up_down", issue = "91399")] + pub fn next_down(self) -> Self { + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. + let bits = self.to_bits(); + if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() { + return self; + } + + let abs = bits & !Self::SIGN_MASK; + let next_bits = if abs == 0 { + Self::NEG_TINY_BITS + } else if bits == abs { + bits - 1 + } else { + bits + 1 + }; + Self::from_bits(next_bits) + } + + /// Takes the reciprocal (inverse) of a number, `1/x`. + /// + /// ``` + /// #![feature(f16)] + /// # // FIXME(f16_f128): remove when `extendhfsf2` and `truncsfhf2` are available + /// # #[cfg(target_os = "linux")] { + /// + /// let x = 2.0_f16; + /// let abs_difference = (x.recip() - (1.0 / x)).abs(); + /// + /// assert!(abs_difference <= f16::EPSILON); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn recip(self) -> Self { + 1.0 / self + } + + /// Converts radians to degrees. + /// + /// ``` + /// #![feature(f16)] + /// # // FIXME(f16_f128): remove when `extendhfsf2` and `truncsfhf2` are available + /// # #[cfg(target_os = "linux")] { + /// + /// let angle = std::f16::consts::PI; + /// + /// let abs_difference = (angle.to_degrees() - 180.0).abs(); + /// assert!(abs_difference <= 0.5); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_degrees(self) -> Self { + // Use a literal for better precision. + const PIS_IN_180: f16 = 57.2957795130823208767981548141051703_f16; + self * PIS_IN_180 + } + + /// Converts degrees to radians. + /// + /// ``` + /// #![feature(f16)] + /// # // FIXME(f16_f128): remove when `extendhfsf2` and `truncsfhf2` are available + /// # #[cfg(target_os = "linux")] { + /// + /// let angle = 180.0f16; + /// + /// let abs_difference = (angle.to_radians() - std::f16::consts::PI).abs(); + /// + /// assert!(abs_difference <= 0.01); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_radians(self) -> f16 { + // Use a literal for better precision. + const RADS_PER_DEG: f16 = 0.017453292519943295769236907684886_f16; + self * RADS_PER_DEG + } + + /// Rounds toward zero and converts to any primitive integer type, + /// assuming that the value is finite and fits in that type. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let value = 4.6_f16; + /// let rounded = unsafe { value.to_int_unchecked::() }; + /// assert_eq!(rounded, 4); + /// + /// let value = -128.9_f16; + /// let rounded = unsafe { value.to_int_unchecked::() }; + /// assert_eq!(rounded, i8::MIN); + /// # } + /// ``` + /// + /// # Safety + /// + /// The value must: + /// + /// * Not be `NaN` + /// * Not be infinite + /// * Be representable in the return type `Int`, after truncating off its fractional part + #[inline] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub unsafe fn to_int_unchecked(self) -> Int + where + Self: FloatToInt, + { + // SAFETY: the caller must uphold the safety contract for + // `FloatToInt::to_int_unchecked`. + unsafe { FloatToInt::::to_int_unchecked(self) } + } + /// Raw transmutation to `u16`. /// /// This is currently identical to `transmute::(self)` on all platforms. @@ -282,6 +616,16 @@ impl f16 { /// /// Note that this function is distinct from `as` casting, which attempts to /// preserve the *numeric* value, and not the bitwise value. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// # // FIXME(f16_f128): enable this once const casting works + /// # // assert_ne!((1f16).to_bits(), 1f16 as u128); // to_bits() is not casting! + /// assert_eq!((12.5f16).to_bits(), 0x4a40); + /// # } + /// ``` #[inline] #[unstable(feature = "f16", issue = "116909")] #[must_use = "this returns the result of the operation, without modifying the original"] @@ -321,6 +665,15 @@ impl f16 { /// /// Note that this function is distinct from `as` casting, which attempts to /// preserve the *numeric* value, and not the bitwise value. + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let v = f16::from_bits(0x4a40); + /// assert_eq!(v, 12.5); + /// # } + /// ``` #[inline] #[must_use] #[unstable(feature = "f16", issue = "116909")] @@ -330,4 +683,293 @@ impl f16 { // Stability concerns. unsafe { mem::transmute(v) } } + + /// Return the memory representation of this floating point number as a byte array in + /// big-endian (network) byte order. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// + /// let bytes = 12.5f16.to_be_bytes(); + /// assert_eq!(bytes, [0x4a, 0x40]); + /// ``` + #[inline] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_be_bytes(self) -> [u8; 2] { + self.to_bits().to_be_bytes() + } + + /// Return the memory representation of this floating point number as a byte array in + /// little-endian byte order. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// + /// let bytes = 12.5f16.to_le_bytes(); + /// assert_eq!(bytes, [0x40, 0x4a]); + /// ``` + #[inline] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_le_bytes(self) -> [u8; 2] { + self.to_bits().to_le_bytes() + } + + /// Return the memory representation of this floating point number as a byte array in + /// native byte order. + /// + /// As the target platform's native endianness is used, portable code + /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, instead. + /// + /// [`to_be_bytes`]: f16::to_be_bytes + /// [`to_le_bytes`]: f16::to_le_bytes + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// + /// let bytes = 12.5f16.to_ne_bytes(); + /// assert_eq!( + /// bytes, + /// if cfg!(target_endian = "big") { + /// [0x4a, 0x40] + /// } else { + /// [0x40, 0x4a] + /// } + /// ); + /// ``` + #[inline] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "this returns the result of the operation, without modifying the original"] + pub fn to_ne_bytes(self) -> [u8; 2] { + self.to_bits().to_ne_bytes() + } + + /// Create a floating point value from its representation as a byte array in big endian. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let value = f16::from_be_bytes([0x4a, 0x40]); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f16", issue = "116909")] + pub fn from_be_bytes(bytes: [u8; 2]) -> Self { + Self::from_bits(u16::from_be_bytes(bytes)) + } + + /// Create a floating point value from its representation as a byte array in little endian. + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let value = f16::from_le_bytes([0x40, 0x4a]); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f16", issue = "116909")] + pub fn from_le_bytes(bytes: [u8; 2]) -> Self { + Self::from_bits(u16::from_le_bytes(bytes)) + } + + /// Create a floating point value from its representation as a byte array in native endian. + /// + /// As the target platform's native endianness is used, portable code + /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as + /// appropriate instead. + /// + /// [`from_be_bytes`]: f16::from_be_bytes + /// [`from_le_bytes`]: f16::from_le_bytes + /// + /// See [`from_bits`](Self::from_bits) for some discussion of the + /// portability of this operation (there are almost no issues). + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// let value = f16::from_ne_bytes(if cfg!(target_endian = "big") { + /// [0x4a, 0x40] + /// } else { + /// [0x40, 0x4a] + /// }); + /// assert_eq!(value, 12.5); + /// # } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "f16", issue = "116909")] + pub fn from_ne_bytes(bytes: [u8; 2]) -> Self { + Self::from_bits(u16::from_ne_bytes(bytes)) + } + + /// Return the ordering between `self` and `other`. + /// + /// Unlike the standard partial comparison between floating point numbers, + /// this comparison always produces an ordering in accordance to + /// the `totalOrder` predicate as defined in the IEEE 754 (2008 revision) + /// floating point standard. The values are ordered in the following sequence: + /// + /// - negative quiet NaN + /// - negative signaling NaN + /// - negative infinity + /// - negative numbers + /// - negative subnormal numbers + /// - negative zero + /// - positive zero + /// - positive subnormal numbers + /// - positive numbers + /// - positive infinity + /// - positive signaling NaN + /// - positive quiet NaN. + /// + /// The ordering established by this function does not always agree with the + /// [`PartialOrd`] and [`PartialEq`] implementations of `f16`. For example, + /// they consider negative and positive zero equal, while `total_cmp` + /// doesn't. + /// + /// The interpretation of the signaling NaN bit follows the definition in + /// the IEEE 754 standard, which may not match the interpretation by some of + /// the older, non-conformant (e.g. MIPS) hardware implementations. + /// + /// # Example + /// + /// ``` + /// #![feature(f16)] + /// + /// struct GoodBoy { + /// name: &'static str, + /// weight: f16, + /// } + /// + /// let mut bois = vec![ + /// GoodBoy { name: "Pucci", weight: 0.1 }, + /// GoodBoy { name: "Woofer", weight: 99.0 }, + /// GoodBoy { name: "Yapper", weight: 10.0 }, + /// GoodBoy { name: "Chonk", weight: f16::INFINITY }, + /// GoodBoy { name: "Abs. Unit", weight: f16::NAN }, + /// GoodBoy { name: "Floaty", weight: -5.0 }, + /// ]; + /// + /// bois.sort_by(|a, b| a.weight.total_cmp(&b.weight)); + /// + /// // `f16::NAN` could be positive or negative, which will affect the sort order. + /// if f16::NAN.is_sign_negative() { + /// bois.into_iter().map(|b| b.weight) + /// .zip([f16::NAN, -5.0, 0.1, 10.0, 99.0, f16::INFINITY].iter()) + /// .for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits())) + /// } else { + /// bois.into_iter().map(|b| b.weight) + /// .zip([-5.0, 0.1, 10.0, 99.0, f16::INFINITY, f16::NAN].iter()) + /// .for_each(|(a, b)| assert_eq!(a.to_bits(), b.to_bits())) + /// } + /// ``` + #[inline] + #[must_use] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + pub fn total_cmp(&self, other: &Self) -> crate::cmp::Ordering { + let mut left = self.to_bits() as i16; + let mut right = other.to_bits() as i16; + + // In case of negatives, flip all the bits except the sign + // to achieve a similar layout as two's complement integers + // + // Why does this work? IEEE 754 floats consist of three fields: + // Sign bit, exponent and mantissa. The set of exponent and mantissa + // fields as a whole have the property that their bitwise order is + // equal to the numeric magnitude where the magnitude is defined. + // The magnitude is not normally defined on NaN values, but + // IEEE 754 totalOrder defines the NaN values also to follow the + // bitwise order. This leads to order explained in the doc comment. + // However, the representation of magnitude is the same for negative + // and positive numbers – only the sign bit is different. + // To easily compare the floats as signed integers, we need to + // flip the exponent and mantissa bits in case of negative numbers. + // We effectively convert the numbers to "two's complement" form. + // + // To do the flipping, we construct a mask and XOR against it. + // We branchlessly calculate an "all-ones except for the sign bit" + // mask from negative-signed values: right shifting sign-extends + // the integer, so we "fill" the mask with sign bits, and then + // convert to unsigned to push one more zero bit. + // On positive values, the mask is all zeros, so it's a no-op. + left ^= (((left >> 15) as u16) >> 1) as i16; + right ^= (((right >> 15) as u16) >> 1) as i16; + + left.cmp(&right) + } + + /// Restrict a value to a certain interval unless it is NaN. + /// + /// Returns `max` if `self` is greater than `max`, and `min` if `self` is + /// less than `min`. Otherwise this returns `self`. + /// + /// Note that this function returns NaN if the initial value was NaN as + /// well. + /// + /// # Panics + /// + /// Panics if `min > max`, `min` is NaN, or `max` is NaN. + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(target_arch = "aarch64")] { // FIXME(f16_F128): rust-lang/rust#123885 + /// + /// assert!((-3.0f16).clamp(-2.0, 1.0) == -2.0); + /// assert!((0.0f16).clamp(-2.0, 1.0) == 0.0); + /// assert!((2.0f16).clamp(-2.0, 1.0) == 1.0); + /// assert!((f16::NAN).clamp(-2.0, 1.0).is_nan()); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "method returns a new number and does not mutate the original value"] + pub fn clamp(mut self, min: f16, max: f16) -> f16 { + assert!(min <= max, "min > max, or either was NaN. min = {min:?}, max = {max:?}"); + if self < min { + self = min; + } + if self > max { + self = max; + } + self + } } diff --git a/library/core/src/num/f32.rs b/library/core/src/num/f32.rs index 9d34d3da9e955..b9c84a66ed138 100644 --- a/library/core/src/num/f32.rs +++ b/library/core/src/num/f32.rs @@ -490,6 +490,21 @@ impl f32 { #[stable(feature = "assoc_int_consts", since = "1.43.0")] pub const NEG_INFINITY: f32 = -1.0_f32 / 0.0_f32; + /// Sign bit + const SIGN_MASK: u32 = 0x8000_0000; + + /// Exponent mask + const EXP_MASK: u32 = 0x7f80_0000; + + /// Mantissa mask + const MAN_MASK: u32 = 0x007f_ffff; + + /// Minimum representable positive value (min subnormal) + const TINY_BITS: u32 = 0x1; + + /// Minimum representable negative value (min negative subnormal) + const NEG_TINY_BITS: u32 = Self::TINY_BITS | Self::SIGN_MASK; + /// Returns `true` if this value is NaN. /// /// ``` @@ -515,7 +530,7 @@ impl f32 { #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] pub(crate) const fn abs_private(self) -> f32 { // SAFETY: This transmutation is fine. Probably. For the reasons std is using it. - unsafe { mem::transmute::(mem::transmute::(self) & 0x7fff_ffff) } + unsafe { mem::transmute::(mem::transmute::(self) & !Self::SIGN_MASK) } } /// Returns `true` if this value is positive infinity or negative infinity, and @@ -682,12 +697,9 @@ impl f32 { // runtime-deviating logic which may or may not be acceptable. #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] const unsafe fn partial_classify(self) -> FpCategory { - const EXP_MASK: u32 = 0x7f800000; - const MAN_MASK: u32 = 0x007fffff; - // SAFETY: The caller is not asking questions for which this will tell lies. let b = unsafe { mem::transmute::(self) }; - match (b & MAN_MASK, b & EXP_MASK) { + match (b & Self::MAN_MASK, b & Self::EXP_MASK) { (0, 0) => FpCategory::Zero, (_, 0) => FpCategory::Subnormal, _ => FpCategory::Normal, @@ -699,12 +711,9 @@ impl f32 { // plus a transmute. We do not live in a just world, but we can make it more so. #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] const fn classify_bits(b: u32) -> FpCategory { - const EXP_MASK: u32 = 0x7f800000; - const MAN_MASK: u32 = 0x007fffff; - - match (b & MAN_MASK, b & EXP_MASK) { - (0, EXP_MASK) => FpCategory::Infinite, - (_, EXP_MASK) => FpCategory::Nan, + match (b & Self::MAN_MASK, b & Self::EXP_MASK) { + (0, Self::EXP_MASK) => FpCategory::Infinite, + (_, Self::EXP_MASK) => FpCategory::Nan, (0, 0) => FpCategory::Zero, (_, 0) => FpCategory::Subnormal, _ => FpCategory::Normal, @@ -787,19 +796,17 @@ impl f32 { #[unstable(feature = "float_next_up_down", issue = "91399")] #[rustc_const_unstable(feature = "float_next_up_down", issue = "91399")] pub const fn next_up(self) -> Self { - // We must use strictly integer arithmetic to prevent denormals from - // flushing to zero after an arithmetic operation on some platforms. - const TINY_BITS: u32 = 0x1; // Smallest positive f32. - const CLEAR_SIGN_MASK: u32 = 0x7fff_ffff; - + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. let bits = self.to_bits(); if self.is_nan() || bits == Self::INFINITY.to_bits() { return self; } - let abs = bits & CLEAR_SIGN_MASK; + let abs = bits & !Self::SIGN_MASK; let next_bits = if abs == 0 { - TINY_BITS + Self::TINY_BITS } else if bits == abs { bits + 1 } else { @@ -837,19 +844,17 @@ impl f32 { #[unstable(feature = "float_next_up_down", issue = "91399")] #[rustc_const_unstable(feature = "float_next_up_down", issue = "91399")] pub const fn next_down(self) -> Self { - // We must use strictly integer arithmetic to prevent denormals from - // flushing to zero after an arithmetic operation on some platforms. - const NEG_TINY_BITS: u32 = 0x8000_0001; // Smallest (in magnitude) negative f32. - const CLEAR_SIGN_MASK: u32 = 0x7fff_ffff; - + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. let bits = self.to_bits(); if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() { return self; } - let abs = bits & CLEAR_SIGN_MASK; + let abs = bits & !Self::SIGN_MASK; let next_bits = if abs == 0 { - NEG_TINY_BITS + Self::NEG_TINY_BITS } else if bits == abs { bits - 1 } else { diff --git a/library/core/src/num/f64.rs b/library/core/src/num/f64.rs index 95f021b2541ab..f8e4555fc44f2 100644 --- a/library/core/src/num/f64.rs +++ b/library/core/src/num/f64.rs @@ -489,6 +489,21 @@ impl f64 { #[stable(feature = "assoc_int_consts", since = "1.43.0")] pub const NEG_INFINITY: f64 = -1.0_f64 / 0.0_f64; + /// Sign bit + const SIGN_MASK: u64 = 0x8000_0000_0000_0000; + + /// Exponent mask + const EXP_MASK: u64 = 0x7ff0_0000_0000_0000; + + /// Mantissa mask + const MAN_MASK: u64 = 0x000f_ffff_ffff_ffff; + + /// Minimum representable positive value (min subnormal) + const TINY_BITS: u64 = 0x1; + + /// Minimum representable negative value (min negative subnormal) + const NEG_TINY_BITS: u64 = Self::TINY_BITS | Self::SIGN_MASK; + /// Returns `true` if this value is NaN. /// /// ``` @@ -514,9 +529,7 @@ impl f64 { #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] pub(crate) const fn abs_private(self) -> f64 { // SAFETY: This transmutation is fine. Probably. For the reasons std is using it. - unsafe { - mem::transmute::(mem::transmute::(self) & 0x7fff_ffff_ffff_ffff) - } + unsafe { mem::transmute::(mem::transmute::(self) & !Self::SIGN_MASK) } } /// Returns `true` if this value is positive infinity or negative infinity, and @@ -673,13 +686,10 @@ impl f64 { // and some normal floating point numbers truncated from an x87 FPU. #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] const unsafe fn partial_classify(self) -> FpCategory { - const EXP_MASK: u64 = 0x7ff0000000000000; - const MAN_MASK: u64 = 0x000fffffffffffff; - // SAFETY: The caller is not asking questions for which this will tell lies. let b = unsafe { mem::transmute::(self) }; - match (b & MAN_MASK, b & EXP_MASK) { - (0, EXP_MASK) => FpCategory::Infinite, + match (b & Self::MAN_MASK, b & Self::EXP_MASK) { + (0, Self::EXP_MASK) => FpCategory::Infinite, (0, 0) => FpCategory::Zero, (_, 0) => FpCategory::Subnormal, _ => FpCategory::Normal, @@ -691,12 +701,9 @@ impl f64 { // plus a transmute. We do not live in a just world, but we can make it more so. #[rustc_const_unstable(feature = "const_float_classify", issue = "72505")] const fn classify_bits(b: u64) -> FpCategory { - const EXP_MASK: u64 = 0x7ff0000000000000; - const MAN_MASK: u64 = 0x000fffffffffffff; - - match (b & MAN_MASK, b & EXP_MASK) { - (0, EXP_MASK) => FpCategory::Infinite, - (_, EXP_MASK) => FpCategory::Nan, + match (b & Self::MAN_MASK, b & Self::EXP_MASK) { + (0, Self::EXP_MASK) => FpCategory::Infinite, + (_, Self::EXP_MASK) => FpCategory::Nan, (0, 0) => FpCategory::Zero, (_, 0) => FpCategory::Subnormal, _ => FpCategory::Normal, @@ -756,7 +763,7 @@ impl f64 { // IEEE754 says: isSignMinus(x) is true if and only if x has negative sign. isSignMinus // applies to zeros and NaNs as well. // SAFETY: This is just transmuting to get the sign bit, it's fine. - unsafe { mem::transmute::(self) & 0x8000_0000_0000_0000 != 0 } + unsafe { mem::transmute::(self) & Self::SIGN_MASK != 0 } } #[must_use] @@ -797,19 +804,17 @@ impl f64 { #[unstable(feature = "float_next_up_down", issue = "91399")] #[rustc_const_unstable(feature = "float_next_up_down", issue = "91399")] pub const fn next_up(self) -> Self { - // We must use strictly integer arithmetic to prevent denormals from - // flushing to zero after an arithmetic operation on some platforms. - const TINY_BITS: u64 = 0x1; // Smallest positive f64. - const CLEAR_SIGN_MASK: u64 = 0x7fff_ffff_ffff_ffff; - + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. let bits = self.to_bits(); if self.is_nan() || bits == Self::INFINITY.to_bits() { return self; } - let abs = bits & CLEAR_SIGN_MASK; + let abs = bits & !Self::SIGN_MASK; let next_bits = if abs == 0 { - TINY_BITS + Self::TINY_BITS } else if bits == abs { bits + 1 } else { @@ -847,19 +852,17 @@ impl f64 { #[unstable(feature = "float_next_up_down", issue = "91399")] #[rustc_const_unstable(feature = "float_next_up_down", issue = "91399")] pub const fn next_down(self) -> Self { - // We must use strictly integer arithmetic to prevent denormals from - // flushing to zero after an arithmetic operation on some platforms. - const NEG_TINY_BITS: u64 = 0x8000_0000_0000_0001; // Smallest (in magnitude) negative f64. - const CLEAR_SIGN_MASK: u64 = 0x7fff_ffff_ffff_ffff; - + // Some targets violate Rust's assumption of IEEE semantics, e.g. by flushing + // denormals to zero. This is in general unsound and unsupported, but here + // we do our best to still produce the correct result on such targets. let bits = self.to_bits(); if self.is_nan() || bits == Self::NEG_INFINITY.to_bits() { return self; } - let abs = bits & CLEAR_SIGN_MASK; + let abs = bits & !Self::SIGN_MASK; let next_bits = if abs == 0 { - NEG_TINY_BITS + Self::NEG_TINY_BITS } else if bits == abs { bits - 1 } else { diff --git a/library/std/build.rs b/library/std/build.rs index 7d975df545ecf..55388648a14b9 100644 --- a/library/std/build.rs +++ b/library/std/build.rs @@ -7,6 +7,10 @@ fn main() { let target_vendor = env::var("CARGO_CFG_TARGET_VENDOR").expect("CARGO_CFG_TARGET_VENDOR was not set"); let target_env = env::var("CARGO_CFG_TARGET_ENV").expect("CARGO_CFG_TARGET_ENV was not set"); + let target_pointer_width: u32 = env::var("CARGO_CFG_TARGET_POINTER_WIDTH") + .expect("CARGO_CFG_TARGET_POINTER_WIDTH was not set") + .parse() + .unwrap(); println!("cargo:rustc-check-cfg=cfg(netbsd10)"); if target_os == "netbsd" && env::var("RUSTC_STD_NETBSD10").is_ok() { @@ -70,4 +74,62 @@ fn main() { println!("cargo:rustc-cfg=backtrace_in_libstd"); println!("cargo:rustc-env=STD_ENV_ARCH={}", env::var("CARGO_CFG_TARGET_ARCH").unwrap()); + + // Emit these on platforms that have no known ABI bugs, LLVM selection bugs, lowering bugs, + // missing symbols, or other problems, to determine when tests get run. + // If more broken platforms are found, please update the tracking issue at + // + // + // Some of these match arms are redundant; the goal is to separate reasons that the type is + // unreliable, even when multiple reasons might fail the same platform. + println!("cargo:rustc-check-cfg=cfg(reliable_f16)"); + println!("cargo:rustc-check-cfg=cfg(reliable_f128)"); + + let has_reliable_f16 = match (target_arch.as_str(), target_os.as_str()) { + // Selection failure until recent LLVM + // FIXME(llvm19): can probably be removed at the version bump + ("loongarch64", _) => false, + // Selection failure + ("s390x", _) => false, + // Unsupported + ("arm64ec", _) => false, + // MinGW ABI bugs + ("x86", "windows") => false, + // x86 has ABI bugs that show up with optimizations. This should be partially fixed with + // the compiler-builtins update. + ("x86" | "x86_64", _) => false, + // Missing `__gnu_h2f_ieee` and `__gnu_f2h_ieee` + ("powerpc" | "powerpc64" | "powerpc64le", _) => false, + // Missing `__extendhfsf` and `__truncsfhf` + ("riscv32" | "riscv64", _) => false, + // Most OSs are missing `__extendhfsf` and `__truncsfhf` + (_, "linux" | "macos") => true, + // Almost all OSs besides Linux and MacOS are missing symbols until compiler-builtins can + // be updated. will get some of these, the + // next CB update should get the rest. + _ => false, + }; + + let has_reliable_f128 = match (target_arch.as_str(), target_os.as_str()) { + // Unsupported + ("arm64ec", _) => false, + // ABI and precision bugs + // + ("powerpc" | "powerpc64", _) => false, + // Selection bug + ("nvptx64", _) => false, + // ABI unsupported + ("sparc", _) => false, + // 64-bit Linux is about the only platform to have f128 symbols by default + (_, "linux") if target_pointer_width == 64 => true, + // Same as for f16, except MacOS is also missing f128 symbols. + _ => false, + }; + + if has_reliable_f16 { + println!("cargo:rustc-cfg=reliable_f16"); + } + if has_reliable_f128 { + println!("cargo:rustc-cfg=reliable_f128"); + } } diff --git a/library/std/src/f128.rs b/library/std/src/f128.rs index 491235a872eaf..0591c6f517b44 100644 --- a/library/std/src/f128.rs +++ b/library/std/src/f128.rs @@ -32,4 +32,34 @@ impl f128 { pub fn powi(self, n: i32) -> f128 { unsafe { intrinsics::powif128(self, n) } } + + /// Computes the absolute value of `self`. + /// + /// This function always returns the precise result. + /// + /// # Examples + /// + /// ``` + /// #![feature(f128)] + /// # #[cfg(reliable_f128)] { // FIXME(f16_f128): reliable_f128 + /// + /// let x = 3.5_f128; + /// let y = -3.5_f128; + /// + /// assert_eq!(x.abs(), x); + /// assert_eq!(y.abs(), -y); + /// + /// assert!(f128::NAN.abs().is_nan()); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[rustc_allow_incoherent_impl] + #[unstable(feature = "f128", issue = "116909")] + #[must_use = "method returns a new number and does not mutate the original value"] + pub fn abs(self) -> Self { + // FIXME(f16_f128): replace with `intrinsics::fabsf128` when available + // We don't do this now because LLVM has lowering bugs for f128 math. + Self::from_bits(self.to_bits() & !(1 << 127)) + } } diff --git a/library/std/src/f128/tests.rs b/library/std/src/f128/tests.rs index b64c7f856a15f..bd7a921c502a7 100644 --- a/library/std/src/f128/tests.rs +++ b/library/std/src/f128/tests.rs @@ -1,29 +1,31 @@ -#![allow(dead_code)] // FIXME(f16_f128): remove once constants are used +#![cfg(not(bootstrap))] +// FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy +#![cfg(reliable_f128)] + +use crate::f128::consts; +use crate::num::*; /// Smallest number const TINY_BITS: u128 = 0x1; + /// Next smallest number const TINY_UP_BITS: u128 = 0x2; + /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0 -const MAX_DOWN_BITS: u128 = 0x7ffeffffffffffffffffffffffffffff; +const MAX_DOWN_BITS: u128 = 0x7ffefffffffffffffffffffffffffffe; + /// Zeroed exponent, full significant const LARGEST_SUBNORMAL_BITS: u128 = 0x0000ffffffffffffffffffffffffffff; + /// Exponent = 0b1, zeroed significand const SMALLEST_NORMAL_BITS: u128 = 0x00010000000000000000000000000000; + /// First pattern over the mantissa const NAN_MASK1: u128 = 0x0000aaaaaaaaaaaaaaaaaaaaaaaaaaaa; + /// Second pattern over the mantissa const NAN_MASK2: u128 = 0x00005555555555555555555555555555; -/// Compare by value -#[allow(unused_macros)] -macro_rules! assert_f128_eq { - ($a:expr, $b:expr) => { - let (l, r): (&f128, &f128) = (&$a, &$b); - assert_eq!(*l, *r, "\na: {:#0130x}\nb: {:#0130x}", l.to_bits(), r.to_bits()) - }; -} - /// Compare by representation #[allow(unused_macros)] macro_rules! assert_f128_biteq { @@ -31,10 +33,503 @@ macro_rules! assert_f128_biteq { let (l, r): (&f128, &f128) = (&$a, &$b); let lb = l.to_bits(); let rb = r.to_bits(); - assert_eq!( - lb, rb, - "float {:?} is not bitequal to {:?}.\na: {:#0130x}\nb: {:#0130x}", - *l, *r, lb, rb - ); + assert_eq!(lb, rb, "float {l:?} is not bitequal to {r:?}.\na: {lb:#034x}\nb: {rb:#034x}"); }; } + +#[test] +fn test_num_f128() { + test_num(10f128, 2f128); +} + +// FIXME(f16_f128): add min and max tests when available + +#[test] +fn test_nan() { + let nan: f128 = f128::NAN; + assert!(nan.is_nan()); + assert!(!nan.is_infinite()); + assert!(!nan.is_finite()); + assert!(nan.is_sign_positive()); + assert!(!nan.is_sign_negative()); + // FIXME(f16_f128): classify + // assert!(!nan.is_normal()); + // assert_eq!(Fp::Nan, nan.classify()); +} + +#[test] +fn test_infinity() { + let inf: f128 = f128::INFINITY; + assert!(inf.is_infinite()); + assert!(!inf.is_finite()); + assert!(inf.is_sign_positive()); + assert!(!inf.is_sign_negative()); + assert!(!inf.is_nan()); + // FIXME(f16_f128): classify + // assert!(!inf.is_normal()); + // assert_eq!(Fp::Infinite, inf.classify()); +} + +#[test] +fn test_neg_infinity() { + let neg_inf: f128 = f128::NEG_INFINITY; + assert!(neg_inf.is_infinite()); + assert!(!neg_inf.is_finite()); + assert!(!neg_inf.is_sign_positive()); + assert!(neg_inf.is_sign_negative()); + assert!(!neg_inf.is_nan()); + // FIXME(f16_f128): classify + // assert!(!neg_inf.is_normal()); + // assert_eq!(Fp::Infinite, neg_inf.classify()); +} + +#[test] +fn test_zero() { + let zero: f128 = 0.0f128; + assert_eq!(0.0, zero); + assert!(!zero.is_infinite()); + assert!(zero.is_finite()); + assert!(zero.is_sign_positive()); + assert!(!zero.is_sign_negative()); + assert!(!zero.is_nan()); + // FIXME(f16_f128): classify + // assert!(!zero.is_normal()); + // assert_eq!(Fp::Zero, zero.classify()); +} + +#[test] +fn test_neg_zero() { + let neg_zero: f128 = -0.0; + assert_eq!(0.0, neg_zero); + assert!(!neg_zero.is_infinite()); + assert!(neg_zero.is_finite()); + assert!(!neg_zero.is_sign_positive()); + assert!(neg_zero.is_sign_negative()); + assert!(!neg_zero.is_nan()); + // FIXME(f16_f128): classify + // assert!(!neg_zero.is_normal()); + // assert_eq!(Fp::Zero, neg_zero.classify()); +} + +#[test] +fn test_one() { + let one: f128 = 1.0f128; + assert_eq!(1.0, one); + assert!(!one.is_infinite()); + assert!(one.is_finite()); + assert!(one.is_sign_positive()); + assert!(!one.is_sign_negative()); + assert!(!one.is_nan()); + // FIXME(f16_f128): classify + // assert!(one.is_normal()); + // assert_eq!(Fp::Normal, one.classify()); +} + +#[test] +fn test_is_nan() { + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert!(nan.is_nan()); + assert!(!0.0f128.is_nan()); + assert!(!5.3f128.is_nan()); + assert!(!(-10.732f128).is_nan()); + assert!(!inf.is_nan()); + assert!(!neg_inf.is_nan()); +} + +#[test] +fn test_is_infinite() { + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert!(!nan.is_infinite()); + assert!(inf.is_infinite()); + assert!(neg_inf.is_infinite()); + assert!(!0.0f128.is_infinite()); + assert!(!42.8f128.is_infinite()); + assert!(!(-109.2f128).is_infinite()); +} + +#[test] +fn test_is_finite() { + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert!(!nan.is_finite()); + assert!(!inf.is_finite()); + assert!(!neg_inf.is_finite()); + assert!(0.0f128.is_finite()); + assert!(42.8f128.is_finite()); + assert!((-109.2f128).is_finite()); +} + +// FIXME(f16_f128): add `test_is_normal` and `test_classify` when classify is working +// FIXME(f16_f128): add missing math functions when available + +#[test] +fn test_abs() { + assert_eq!(f128::INFINITY.abs(), f128::INFINITY); + assert_eq!(1f128.abs(), 1f128); + assert_eq!(0f128.abs(), 0f128); + assert_eq!((-0f128).abs(), 0f128); + assert_eq!((-1f128).abs(), 1f128); + assert_eq!(f128::NEG_INFINITY.abs(), f128::INFINITY); + assert_eq!((1f128 / f128::NEG_INFINITY).abs(), 0f128); + assert!(f128::NAN.abs().is_nan()); +} + +#[test] +fn test_is_sign_positive() { + assert!(f128::INFINITY.is_sign_positive()); + assert!(1f128.is_sign_positive()); + assert!(0f128.is_sign_positive()); + assert!(!(-0f128).is_sign_positive()); + assert!(!(-1f128).is_sign_positive()); + assert!(!f128::NEG_INFINITY.is_sign_positive()); + assert!(!(1f128 / f128::NEG_INFINITY).is_sign_positive()); + assert!(f128::NAN.is_sign_positive()); + assert!(!(-f128::NAN).is_sign_positive()); +} + +#[test] +fn test_is_sign_negative() { + assert!(!f128::INFINITY.is_sign_negative()); + assert!(!1f128.is_sign_negative()); + assert!(!0f128.is_sign_negative()); + assert!((-0f128).is_sign_negative()); + assert!((-1f128).is_sign_negative()); + assert!(f128::NEG_INFINITY.is_sign_negative()); + assert!((1f128 / f128::NEG_INFINITY).is_sign_negative()); + assert!(!f128::NAN.is_sign_negative()); + assert!((-f128::NAN).is_sign_negative()); +} + +#[test] +fn test_next_up() { + let tiny = f128::from_bits(TINY_BITS); + let tiny_up = f128::from_bits(TINY_UP_BITS); + let max_down = f128::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f128::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f128::from_bits(SMALLEST_NORMAL_BITS); + assert_f128_biteq!(f128::NEG_INFINITY.next_up(), f128::MIN); + assert_f128_biteq!(f128::MIN.next_up(), -max_down); + assert_f128_biteq!((-1.0 - f128::EPSILON).next_up(), -1.0); + assert_f128_biteq!((-smallest_normal).next_up(), -largest_subnormal); + assert_f128_biteq!((-tiny_up).next_up(), -tiny); + assert_f128_biteq!((-tiny).next_up(), -0.0f128); + assert_f128_biteq!((-0.0f128).next_up(), tiny); + assert_f128_biteq!(0.0f128.next_up(), tiny); + assert_f128_biteq!(tiny.next_up(), tiny_up); + assert_f128_biteq!(largest_subnormal.next_up(), smallest_normal); + assert_f128_biteq!(1.0f128.next_up(), 1.0 + f128::EPSILON); + assert_f128_biteq!(f128::MAX.next_up(), f128::INFINITY); + assert_f128_biteq!(f128::INFINITY.next_up(), f128::INFINITY); + + // Check that NaNs roundtrip. + let nan0 = f128::NAN; + let nan1 = f128::from_bits(f128::NAN.to_bits() ^ 0x002a_aaaa); + let nan2 = f128::from_bits(f128::NAN.to_bits() ^ 0x0055_5555); + assert_f128_biteq!(nan0.next_up(), nan0); + assert_f128_biteq!(nan1.next_up(), nan1); + assert_f128_biteq!(nan2.next_up(), nan2); +} + +#[test] +fn test_next_down() { + let tiny = f128::from_bits(TINY_BITS); + let tiny_up = f128::from_bits(TINY_UP_BITS); + let max_down = f128::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f128::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f128::from_bits(SMALLEST_NORMAL_BITS); + assert_f128_biteq!(f128::NEG_INFINITY.next_down(), f128::NEG_INFINITY); + assert_f128_biteq!(f128::MIN.next_down(), f128::NEG_INFINITY); + assert_f128_biteq!((-max_down).next_down(), f128::MIN); + assert_f128_biteq!((-1.0f128).next_down(), -1.0 - f128::EPSILON); + assert_f128_biteq!((-largest_subnormal).next_down(), -smallest_normal); + assert_f128_biteq!((-tiny).next_down(), -tiny_up); + assert_f128_biteq!((-0.0f128).next_down(), -tiny); + assert_f128_biteq!((0.0f128).next_down(), -tiny); + assert_f128_biteq!(tiny.next_down(), 0.0f128); + assert_f128_biteq!(tiny_up.next_down(), tiny); + assert_f128_biteq!(smallest_normal.next_down(), largest_subnormal); + assert_f128_biteq!((1.0 + f128::EPSILON).next_down(), 1.0f128); + assert_f128_biteq!(f128::MAX.next_down(), max_down); + assert_f128_biteq!(f128::INFINITY.next_down(), f128::MAX); + + // Check that NaNs roundtrip. + let nan0 = f128::NAN; + let nan1 = f128::from_bits(f128::NAN.to_bits() ^ 0x002a_aaaa); + let nan2 = f128::from_bits(f128::NAN.to_bits() ^ 0x0055_5555); + assert_f128_biteq!(nan0.next_down(), nan0); + assert_f128_biteq!(nan1.next_down(), nan1); + assert_f128_biteq!(nan2.next_down(), nan2); +} + +#[test] +fn test_recip() { + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert_eq!(1.0f128.recip(), 1.0); + assert_eq!(2.0f128.recip(), 0.5); + assert_eq!((-0.4f128).recip(), -2.5); + assert_eq!(0.0f128.recip(), inf); + assert!(nan.recip().is_nan()); + assert_eq!(inf.recip(), 0.0); + assert_eq!(neg_inf.recip(), 0.0); +} + +#[test] +fn test_to_degrees() { + let pi: f128 = consts::PI; + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert_eq!(0.0f128.to_degrees(), 0.0); + assert_approx_eq!((-5.8f128).to_degrees(), -332.315521); + assert_eq!(pi.to_degrees(), 180.0); + assert!(nan.to_degrees().is_nan()); + assert_eq!(inf.to_degrees(), inf); + assert_eq!(neg_inf.to_degrees(), neg_inf); + assert_eq!(1_f128.to_degrees(), 57.2957795130823208767981548141051703); +} + +#[test] +fn test_to_radians() { + let pi: f128 = consts::PI; + let nan: f128 = f128::NAN; + let inf: f128 = f128::INFINITY; + let neg_inf: f128 = f128::NEG_INFINITY; + assert_eq!(0.0f128.to_radians(), 0.0); + assert_approx_eq!(154.6f128.to_radians(), 2.698279); + assert_approx_eq!((-332.31f128).to_radians(), -5.799903); + // check approx rather than exact because round trip for pi doesn't fall on an exactly + // representable value (unlike `f32` and `f64`). + assert_approx_eq!(180.0f128.to_radians(), pi); + assert!(nan.to_radians().is_nan()); + assert_eq!(inf.to_radians(), inf); + assert_eq!(neg_inf.to_radians(), neg_inf); +} + +#[test] +fn test_real_consts() { + // FIXME(f16_f128): add math tests when available + use super::consts; + + let pi: f128 = consts::PI; + let frac_pi_2: f128 = consts::FRAC_PI_2; + let frac_pi_3: f128 = consts::FRAC_PI_3; + let frac_pi_4: f128 = consts::FRAC_PI_4; + let frac_pi_6: f128 = consts::FRAC_PI_6; + let frac_pi_8: f128 = consts::FRAC_PI_8; + let frac_1_pi: f128 = consts::FRAC_1_PI; + let frac_2_pi: f128 = consts::FRAC_2_PI; + // let frac_2_sqrtpi: f128 = consts::FRAC_2_SQRT_PI; + // let sqrt2: f128 = consts::SQRT_2; + // let frac_1_sqrt2: f128 = consts::FRAC_1_SQRT_2; + // let e: f128 = consts::E; + // let log2_e: f128 = consts::LOG2_E; + // let log10_e: f128 = consts::LOG10_E; + // let ln_2: f128 = consts::LN_2; + // let ln_10: f128 = consts::LN_10; + + assert_approx_eq!(frac_pi_2, pi / 2f128); + assert_approx_eq!(frac_pi_3, pi / 3f128); + assert_approx_eq!(frac_pi_4, pi / 4f128); + assert_approx_eq!(frac_pi_6, pi / 6f128); + assert_approx_eq!(frac_pi_8, pi / 8f128); + assert_approx_eq!(frac_1_pi, 1f128 / pi); + assert_approx_eq!(frac_2_pi, 2f128 / pi); + // assert_approx_eq!(frac_2_sqrtpi, 2f128 / pi.sqrt()); + // assert_approx_eq!(sqrt2, 2f128.sqrt()); + // assert_approx_eq!(frac_1_sqrt2, 1f128 / 2f128.sqrt()); + // assert_approx_eq!(log2_e, e.log2()); + // assert_approx_eq!(log10_e, e.log10()); + // assert_approx_eq!(ln_2, 2f128.ln()); + // assert_approx_eq!(ln_10, 10f128.ln()); +} + +#[test] +fn test_float_bits_conv() { + assert_eq!((1f128).to_bits(), 0x3fff0000000000000000000000000000); + assert_eq!((12.5f128).to_bits(), 0x40029000000000000000000000000000); + assert_eq!((1337f128).to_bits(), 0x40094e40000000000000000000000000); + assert_eq!((-14.25f128).to_bits(), 0xc002c800000000000000000000000000); + assert_approx_eq!(f128::from_bits(0x3fff0000000000000000000000000000), 1.0); + assert_approx_eq!(f128::from_bits(0x40029000000000000000000000000000), 12.5); + assert_approx_eq!(f128::from_bits(0x40094e40000000000000000000000000), 1337.0); + assert_approx_eq!(f128::from_bits(0xc002c800000000000000000000000000), -14.25); + + // Check that NaNs roundtrip their bits regardless of signaling-ness + // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits + let masked_nan1 = f128::NAN.to_bits() ^ NAN_MASK1; + let masked_nan2 = f128::NAN.to_bits() ^ NAN_MASK2; + assert!(f128::from_bits(masked_nan1).is_nan()); + assert!(f128::from_bits(masked_nan2).is_nan()); + + assert_eq!(f128::from_bits(masked_nan1).to_bits(), masked_nan1); + assert_eq!(f128::from_bits(masked_nan2).to_bits(), masked_nan2); +} + +#[test] +#[should_panic] +fn test_clamp_min_greater_than_max() { + let _ = 1.0f128.clamp(3.0, 1.0); +} + +#[test] +#[should_panic] +fn test_clamp_min_is_nan() { + let _ = 1.0f128.clamp(f128::NAN, 1.0); +} + +#[test] +#[should_panic] +fn test_clamp_max_is_nan() { + let _ = 1.0f128.clamp(3.0, f128::NAN); +} + +#[test] +fn test_total_cmp() { + use core::cmp::Ordering; + + fn quiet_bit_mask() -> u128 { + 1 << (f128::MANTISSA_DIGITS - 2) + } + + // FIXME(f16_f128): test subnormals when powf is available + // fn min_subnorm() -> f128 { + // f128::MIN_POSITIVE / f128::powf(2.0, f128::MANTISSA_DIGITS as f128 - 1.0) + // } + + // fn max_subnorm() -> f128 { + // f128::MIN_POSITIVE - min_subnorm() + // } + + fn q_nan() -> f128 { + f128::from_bits(f128::NAN.to_bits() | quiet_bit_mask()) + } + + fn s_nan() -> f128 { + f128::from_bits((f128::NAN.to_bits() & !quiet_bit_mask()) + 42) + } + + assert_eq!(Ordering::Equal, (-q_nan()).total_cmp(&-q_nan())); + assert_eq!(Ordering::Equal, (-s_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Equal, (-f128::INFINITY).total_cmp(&-f128::INFINITY)); + assert_eq!(Ordering::Equal, (-f128::MAX).total_cmp(&-f128::MAX)); + assert_eq!(Ordering::Equal, (-2.5_f128).total_cmp(&-2.5)); + assert_eq!(Ordering::Equal, (-1.0_f128).total_cmp(&-1.0)); + assert_eq!(Ordering::Equal, (-1.5_f128).total_cmp(&-1.5)); + assert_eq!(Ordering::Equal, (-0.5_f128).total_cmp(&-0.5)); + assert_eq!(Ordering::Equal, (-f128::MIN_POSITIVE).total_cmp(&-f128::MIN_POSITIVE)); + // assert_eq!(Ordering::Equal, (-max_subnorm()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Equal, (-min_subnorm()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Equal, (-0.0_f128).total_cmp(&-0.0)); + assert_eq!(Ordering::Equal, 0.0_f128.total_cmp(&0.0)); + // assert_eq!(Ordering::Equal, min_subnorm().total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Equal, max_subnorm().total_cmp(&max_subnorm())); + assert_eq!(Ordering::Equal, f128::MIN_POSITIVE.total_cmp(&f128::MIN_POSITIVE)); + assert_eq!(Ordering::Equal, 0.5_f128.total_cmp(&0.5)); + assert_eq!(Ordering::Equal, 1.0_f128.total_cmp(&1.0)); + assert_eq!(Ordering::Equal, 1.5_f128.total_cmp(&1.5)); + assert_eq!(Ordering::Equal, 2.5_f128.total_cmp(&2.5)); + assert_eq!(Ordering::Equal, f128::MAX.total_cmp(&f128::MAX)); + assert_eq!(Ordering::Equal, f128::INFINITY.total_cmp(&f128::INFINITY)); + assert_eq!(Ordering::Equal, s_nan().total_cmp(&s_nan())); + assert_eq!(Ordering::Equal, q_nan().total_cmp(&q_nan())); + + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f128::INFINITY)); + assert_eq!(Ordering::Less, (-f128::INFINITY).total_cmp(&-f128::MAX)); + assert_eq!(Ordering::Less, (-f128::MAX).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-2.5_f128).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-1.5_f128).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-1.0_f128).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-0.5_f128).total_cmp(&-f128::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-f128::MIN_POSITIVE).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-max_subnorm()).total_cmp(&-min_subnorm())); + // assert_eq!(Ordering::Less, (-min_subnorm()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-0.0_f128).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, 0.0_f128.total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, min_subnorm().total_cmp(&max_subnorm())); + // assert_eq!(Ordering::Less, max_subnorm().total_cmp(&f128::MIN_POSITIVE)); + assert_eq!(Ordering::Less, f128::MIN_POSITIVE.total_cmp(&0.5)); + assert_eq!(Ordering::Less, 0.5_f128.total_cmp(&1.0)); + assert_eq!(Ordering::Less, 1.0_f128.total_cmp(&1.5)); + assert_eq!(Ordering::Less, 1.5_f128.total_cmp(&2.5)); + assert_eq!(Ordering::Less, 2.5_f128.total_cmp(&f128::MAX)); + assert_eq!(Ordering::Less, f128::MAX.total_cmp(&f128::INFINITY)); + assert_eq!(Ordering::Less, f128::INFINITY.total_cmp(&s_nan())); + assert_eq!(Ordering::Less, s_nan().total_cmp(&q_nan())); + + assert_eq!(Ordering::Greater, (-s_nan()).total_cmp(&-q_nan())); + assert_eq!(Ordering::Greater, (-f128::INFINITY).total_cmp(&-s_nan())); + assert_eq!(Ordering::Greater, (-f128::MAX).total_cmp(&-f128::INFINITY)); + assert_eq!(Ordering::Greater, (-2.5_f128).total_cmp(&-f128::MAX)); + assert_eq!(Ordering::Greater, (-1.5_f128).total_cmp(&-2.5)); + assert_eq!(Ordering::Greater, (-1.0_f128).total_cmp(&-1.5)); + assert_eq!(Ordering::Greater, (-0.5_f128).total_cmp(&-1.0)); + assert_eq!(Ordering::Greater, (-f128::MIN_POSITIVE).total_cmp(&-0.5)); + // assert_eq!(Ordering::Greater, (-max_subnorm()).total_cmp(&-f128::MIN_POSITIVE)); + // assert_eq!(Ordering::Greater, (-min_subnorm()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Greater, (-0.0_f128).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Greater, 0.0_f128.total_cmp(&-0.0)); + // assert_eq!(Ordering::Greater, min_subnorm().total_cmp(&0.0)); + // assert_eq!(Ordering::Greater, max_subnorm().total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Greater, f128::MIN_POSITIVE.total_cmp(&max_subnorm())); + assert_eq!(Ordering::Greater, 0.5_f128.total_cmp(&f128::MIN_POSITIVE)); + assert_eq!(Ordering::Greater, 1.0_f128.total_cmp(&0.5)); + assert_eq!(Ordering::Greater, 1.5_f128.total_cmp(&1.0)); + assert_eq!(Ordering::Greater, 2.5_f128.total_cmp(&1.5)); + assert_eq!(Ordering::Greater, f128::MAX.total_cmp(&2.5)); + assert_eq!(Ordering::Greater, f128::INFINITY.total_cmp(&f128::MAX)); + assert_eq!(Ordering::Greater, s_nan().total_cmp(&f128::INFINITY)); + assert_eq!(Ordering::Greater, q_nan().total_cmp(&s_nan())); + + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f128::INFINITY)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f128::MAX)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f128::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&max_subnorm())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f128::MIN_POSITIVE)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&0.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&1.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&1.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&2.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f128::MAX)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f128::INFINITY)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&s_nan())); + + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f128::INFINITY)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f128::MAX)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f128::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&max_subnorm())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f128::MIN_POSITIVE)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&0.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&1.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&1.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&2.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f128::MAX)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f128::INFINITY)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&s_nan())); +} diff --git a/library/std/src/f16.rs b/library/std/src/f16.rs index 1cb655ffabd84..d48518622999a 100644 --- a/library/std/src/f16.rs +++ b/library/std/src/f16.rs @@ -32,4 +32,33 @@ impl f16 { pub fn powi(self, n: i32) -> f16 { unsafe { intrinsics::powif16(self, n) } } + + /// Computes the absolute value of `self`. + /// + /// This function always returns the precise result. + /// + /// # Examples + /// + /// ``` + /// #![feature(f16)] + /// # #[cfg(reliable_f16)] { + /// + /// let x = 3.5_f16; + /// let y = -3.5_f16; + /// + /// assert_eq!(x.abs(), x); + /// assert_eq!(y.abs(), -y); + /// + /// assert!(f16::NAN.abs().is_nan()); + /// # } + /// ``` + #[inline] + #[cfg(not(bootstrap))] + #[rustc_allow_incoherent_impl] + #[unstable(feature = "f16", issue = "116909")] + #[must_use = "method returns a new number and does not mutate the original value"] + pub fn abs(self) -> Self { + // FIXME(f16_f128): replace with `intrinsics::fabsf16` when available + Self::from_bits(self.to_bits() & !(1 << 15)) + } } diff --git a/library/std/src/f16/tests.rs b/library/std/src/f16/tests.rs index d65c43eca4bb8..bb6a811529e17 100644 --- a/library/std/src/f16/tests.rs +++ b/library/std/src/f16/tests.rs @@ -1,35 +1,37 @@ -#![allow(dead_code)] // FIXME(f16_f128): remove once constants are used +#![cfg(not(bootstrap))] +// FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy +#![cfg(reliable_f16)] + +use crate::f16::consts; +use crate::num::*; // We run out of precision pretty quickly with f16 -const F16_APPROX_L1: f16 = 0.001; +// const F16_APPROX_L1: f16 = 0.001; const F16_APPROX_L2: f16 = 0.01; -const F16_APPROX_L3: f16 = 0.1; +// const F16_APPROX_L3: f16 = 0.1; const F16_APPROX_L4: f16 = 0.5; /// Smallest number const TINY_BITS: u16 = 0x1; + /// Next smallest number const TINY_UP_BITS: u16 = 0x2; + /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0 const MAX_DOWN_BITS: u16 = 0x7bfe; + /// Zeroed exponent, full significant const LARGEST_SUBNORMAL_BITS: u16 = 0x03ff; + /// Exponent = 0b1, zeroed significand const SMALLEST_NORMAL_BITS: u16 = 0x0400; + /// First pattern over the mantissa const NAN_MASK1: u16 = 0x02aa; + /// Second pattern over the mantissa const NAN_MASK2: u16 = 0x0155; -/// Compare by value -#[allow(unused_macros)] -macro_rules! assert_f16_eq { - ($a:expr, $b:expr) => { - let (l, r): (&f16, &f16) = (&$a, &$b); - assert_eq!(*l, *r, "\na: {:#018x}\nb: {:#018x}", l.to_bits(), r.to_bits()) - }; -} - /// Compare by representation #[allow(unused_macros)] macro_rules! assert_f16_biteq { @@ -37,10 +39,500 @@ macro_rules! assert_f16_biteq { let (l, r): (&f16, &f16) = (&$a, &$b); let lb = l.to_bits(); let rb = r.to_bits(); - assert_eq!( - lb, rb, - "float {:?} is not bitequal to {:?}.\na: {:#018x}\nb: {:#018x}", - *l, *r, lb, rb - ); + assert_eq!(lb, rb, "float {l:?} ({lb:#04x}) is not bitequal to {r:?} ({rb:#04x})"); }; } + +#[test] +fn test_num_f16() { + test_num(10f16, 2f16); +} + +// FIXME(f16_f128): add min and max tests when available + +#[test] +fn test_nan() { + let nan: f16 = f16::NAN; + assert!(nan.is_nan()); + assert!(!nan.is_infinite()); + assert!(!nan.is_finite()); + assert!(nan.is_sign_positive()); + assert!(!nan.is_sign_negative()); + // FIXME(f16_f128): classify + // assert!(!nan.is_normal()); + // assert_eq!(Fp::Nan, nan.classify()); +} + +#[test] +fn test_infinity() { + let inf: f16 = f16::INFINITY; + assert!(inf.is_infinite()); + assert!(!inf.is_finite()); + assert!(inf.is_sign_positive()); + assert!(!inf.is_sign_negative()); + assert!(!inf.is_nan()); + // FIXME(f16_f128): classify + // assert!(!inf.is_normal()); + // assert_eq!(Fp::Infinite, inf.classify()); +} + +#[test] +fn test_neg_infinity() { + let neg_inf: f16 = f16::NEG_INFINITY; + assert!(neg_inf.is_infinite()); + assert!(!neg_inf.is_finite()); + assert!(!neg_inf.is_sign_positive()); + assert!(neg_inf.is_sign_negative()); + assert!(!neg_inf.is_nan()); + // FIXME(f16_f128): classify + // assert!(!neg_inf.is_normal()); + // assert_eq!(Fp::Infinite, neg_inf.classify()); +} + +#[test] +fn test_zero() { + let zero: f16 = 0.0f16; + assert_eq!(0.0, zero); + assert!(!zero.is_infinite()); + assert!(zero.is_finite()); + assert!(zero.is_sign_positive()); + assert!(!zero.is_sign_negative()); + assert!(!zero.is_nan()); + // FIXME(f16_f128): classify + // assert!(!zero.is_normal()); + // assert_eq!(Fp::Zero, zero.classify()); +} + +#[test] +fn test_neg_zero() { + let neg_zero: f16 = -0.0; + assert_eq!(0.0, neg_zero); + assert!(!neg_zero.is_infinite()); + assert!(neg_zero.is_finite()); + assert!(!neg_zero.is_sign_positive()); + assert!(neg_zero.is_sign_negative()); + assert!(!neg_zero.is_nan()); + // FIXME(f16_f128): classify + // assert!(!neg_zero.is_normal()); + // assert_eq!(Fp::Zero, neg_zero.classify()); +} + +#[test] +fn test_one() { + let one: f16 = 1.0f16; + assert_eq!(1.0, one); + assert!(!one.is_infinite()); + assert!(one.is_finite()); + assert!(one.is_sign_positive()); + assert!(!one.is_sign_negative()); + assert!(!one.is_nan()); + // FIXME(f16_f128): classify + // assert!(one.is_normal()); + // assert_eq!(Fp::Normal, one.classify()); +} + +#[test] +fn test_is_nan() { + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert!(nan.is_nan()); + assert!(!0.0f16.is_nan()); + assert!(!5.3f16.is_nan()); + assert!(!(-10.732f16).is_nan()); + assert!(!inf.is_nan()); + assert!(!neg_inf.is_nan()); +} + +#[test] +fn test_is_infinite() { + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert!(!nan.is_infinite()); + assert!(inf.is_infinite()); + assert!(neg_inf.is_infinite()); + assert!(!0.0f16.is_infinite()); + assert!(!42.8f16.is_infinite()); + assert!(!(-109.2f16).is_infinite()); +} + +#[test] +fn test_is_finite() { + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert!(!nan.is_finite()); + assert!(!inf.is_finite()); + assert!(!neg_inf.is_finite()); + assert!(0.0f16.is_finite()); + assert!(42.8f16.is_finite()); + assert!((-109.2f16).is_finite()); +} + +// FIXME(f16_f128): add `test_is_normal` and `test_classify` when classify is working +// FIXME(f16_f128): add missing math functions when available + +#[test] +fn test_abs() { + assert_eq!(f16::INFINITY.abs(), f16::INFINITY); + assert_eq!(1f16.abs(), 1f16); + assert_eq!(0f16.abs(), 0f16); + assert_eq!((-0f16).abs(), 0f16); + assert_eq!((-1f16).abs(), 1f16); + assert_eq!(f16::NEG_INFINITY.abs(), f16::INFINITY); + assert_eq!((1f16 / f16::NEG_INFINITY).abs(), 0f16); + assert!(f16::NAN.abs().is_nan()); +} + +#[test] +fn test_is_sign_positive() { + assert!(f16::INFINITY.is_sign_positive()); + assert!(1f16.is_sign_positive()); + assert!(0f16.is_sign_positive()); + assert!(!(-0f16).is_sign_positive()); + assert!(!(-1f16).is_sign_positive()); + assert!(!f16::NEG_INFINITY.is_sign_positive()); + assert!(!(1f16 / f16::NEG_INFINITY).is_sign_positive()); + assert!(f16::NAN.is_sign_positive()); + assert!(!(-f16::NAN).is_sign_positive()); +} + +#[test] +fn test_is_sign_negative() { + assert!(!f16::INFINITY.is_sign_negative()); + assert!(!1f16.is_sign_negative()); + assert!(!0f16.is_sign_negative()); + assert!((-0f16).is_sign_negative()); + assert!((-1f16).is_sign_negative()); + assert!(f16::NEG_INFINITY.is_sign_negative()); + assert!((1f16 / f16::NEG_INFINITY).is_sign_negative()); + assert!(!f16::NAN.is_sign_negative()); + assert!((-f16::NAN).is_sign_negative()); +} + +#[test] +fn test_next_up() { + let tiny = f16::from_bits(TINY_BITS); + let tiny_up = f16::from_bits(TINY_UP_BITS); + let max_down = f16::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f16::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f16::from_bits(SMALLEST_NORMAL_BITS); + assert_f16_biteq!(f16::NEG_INFINITY.next_up(), f16::MIN); + assert_f16_biteq!(f16::MIN.next_up(), -max_down); + assert_f16_biteq!((-1.0 - f16::EPSILON).next_up(), -1.0); + assert_f16_biteq!((-smallest_normal).next_up(), -largest_subnormal); + assert_f16_biteq!((-tiny_up).next_up(), -tiny); + assert_f16_biteq!((-tiny).next_up(), -0.0f16); + assert_f16_biteq!((-0.0f16).next_up(), tiny); + assert_f16_biteq!(0.0f16.next_up(), tiny); + assert_f16_biteq!(tiny.next_up(), tiny_up); + assert_f16_biteq!(largest_subnormal.next_up(), smallest_normal); + assert_f16_biteq!(1.0f16.next_up(), 1.0 + f16::EPSILON); + assert_f16_biteq!(f16::MAX.next_up(), f16::INFINITY); + assert_f16_biteq!(f16::INFINITY.next_up(), f16::INFINITY); + + // Check that NaNs roundtrip. + let nan0 = f16::NAN; + let nan1 = f16::from_bits(f16::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f16::from_bits(f16::NAN.to_bits() ^ NAN_MASK2); + assert_f16_biteq!(nan0.next_up(), nan0); + assert_f16_biteq!(nan1.next_up(), nan1); + assert_f16_biteq!(nan2.next_up(), nan2); +} + +#[test] +fn test_next_down() { + let tiny = f16::from_bits(TINY_BITS); + let tiny_up = f16::from_bits(TINY_UP_BITS); + let max_down = f16::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f16::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f16::from_bits(SMALLEST_NORMAL_BITS); + assert_f16_biteq!(f16::NEG_INFINITY.next_down(), f16::NEG_INFINITY); + assert_f16_biteq!(f16::MIN.next_down(), f16::NEG_INFINITY); + assert_f16_biteq!((-max_down).next_down(), f16::MIN); + assert_f16_biteq!((-1.0f16).next_down(), -1.0 - f16::EPSILON); + assert_f16_biteq!((-largest_subnormal).next_down(), -smallest_normal); + assert_f16_biteq!((-tiny).next_down(), -tiny_up); + assert_f16_biteq!((-0.0f16).next_down(), -tiny); + assert_f16_biteq!((0.0f16).next_down(), -tiny); + assert_f16_biteq!(tiny.next_down(), 0.0f16); + assert_f16_biteq!(tiny_up.next_down(), tiny); + assert_f16_biteq!(smallest_normal.next_down(), largest_subnormal); + assert_f16_biteq!((1.0 + f16::EPSILON).next_down(), 1.0f16); + assert_f16_biteq!(f16::MAX.next_down(), max_down); + assert_f16_biteq!(f16::INFINITY.next_down(), f16::MAX); + + // Check that NaNs roundtrip. + let nan0 = f16::NAN; + let nan1 = f16::from_bits(f16::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f16::from_bits(f16::NAN.to_bits() ^ NAN_MASK2); + assert_f16_biteq!(nan0.next_down(), nan0); + assert_f16_biteq!(nan1.next_down(), nan1); + assert_f16_biteq!(nan2.next_down(), nan2); +} + +#[test] +fn test_recip() { + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert_eq!(1.0f16.recip(), 1.0); + assert_eq!(2.0f16.recip(), 0.5); + assert_eq!((-0.4f16).recip(), -2.5); + assert_eq!(0.0f16.recip(), inf); + assert!(nan.recip().is_nan()); + assert_eq!(inf.recip(), 0.0); + assert_eq!(neg_inf.recip(), 0.0); +} + +#[test] +fn test_to_degrees() { + let pi: f16 = consts::PI; + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert_eq!(0.0f16.to_degrees(), 0.0); + assert_approx_eq!((-5.8f16).to_degrees(), -332.315521); + assert_approx_eq!(pi.to_degrees(), 180.0, F16_APPROX_L4); + assert!(nan.to_degrees().is_nan()); + assert_eq!(inf.to_degrees(), inf); + assert_eq!(neg_inf.to_degrees(), neg_inf); + assert_eq!(1_f16.to_degrees(), 57.2957795130823208767981548141051703); +} + +#[test] +fn test_to_radians() { + let pi: f16 = consts::PI; + let nan: f16 = f16::NAN; + let inf: f16 = f16::INFINITY; + let neg_inf: f16 = f16::NEG_INFINITY; + assert_eq!(0.0f16.to_radians(), 0.0); + assert_approx_eq!(154.6f16.to_radians(), 2.698279); + assert_approx_eq!((-332.31f16).to_radians(), -5.799903); + assert_approx_eq!(180.0f16.to_radians(), pi, F16_APPROX_L2); + assert!(nan.to_radians().is_nan()); + assert_eq!(inf.to_radians(), inf); + assert_eq!(neg_inf.to_radians(), neg_inf); +} + +#[test] +fn test_real_consts() { + // FIXME(f16_f128): add math tests when available + use super::consts; + + let pi: f16 = consts::PI; + let frac_pi_2: f16 = consts::FRAC_PI_2; + let frac_pi_3: f16 = consts::FRAC_PI_3; + let frac_pi_4: f16 = consts::FRAC_PI_4; + let frac_pi_6: f16 = consts::FRAC_PI_6; + let frac_pi_8: f16 = consts::FRAC_PI_8; + let frac_1_pi: f16 = consts::FRAC_1_PI; + let frac_2_pi: f16 = consts::FRAC_2_PI; + // let frac_2_sqrtpi: f16 = consts::FRAC_2_SQRT_PI; + // let sqrt2: f16 = consts::SQRT_2; + // let frac_1_sqrt2: f16 = consts::FRAC_1_SQRT_2; + // let e: f16 = consts::E; + // let log2_e: f16 = consts::LOG2_E; + // let log10_e: f16 = consts::LOG10_E; + // let ln_2: f16 = consts::LN_2; + // let ln_10: f16 = consts::LN_10; + + assert_approx_eq!(frac_pi_2, pi / 2f16); + assert_approx_eq!(frac_pi_3, pi / 3f16); + assert_approx_eq!(frac_pi_4, pi / 4f16); + assert_approx_eq!(frac_pi_6, pi / 6f16); + assert_approx_eq!(frac_pi_8, pi / 8f16); + assert_approx_eq!(frac_1_pi, 1f16 / pi); + assert_approx_eq!(frac_2_pi, 2f16 / pi); + // assert_approx_eq!(frac_2_sqrtpi, 2f16 / pi.sqrt()); + // assert_approx_eq!(sqrt2, 2f16.sqrt()); + // assert_approx_eq!(frac_1_sqrt2, 1f16 / 2f16.sqrt()); + // assert_approx_eq!(log2_e, e.log2()); + // assert_approx_eq!(log10_e, e.log10()); + // assert_approx_eq!(ln_2, 2f16.ln()); + // assert_approx_eq!(ln_10, 10f16.ln()); +} + +#[test] +fn test_float_bits_conv() { + assert_eq!((1f16).to_bits(), 0x3c00); + assert_eq!((12.5f16).to_bits(), 0x4a40); + assert_eq!((1337f16).to_bits(), 0x6539); + assert_eq!((-14.25f16).to_bits(), 0xcb20); + assert_approx_eq!(f16::from_bits(0x3c00), 1.0); + assert_approx_eq!(f16::from_bits(0x4a40), 12.5); + assert_approx_eq!(f16::from_bits(0x6539), 1337.0); + assert_approx_eq!(f16::from_bits(0xcb20), -14.25); + + // Check that NaNs roundtrip their bits regardless of signaling-ness + let masked_nan1 = f16::NAN.to_bits() ^ NAN_MASK1; + let masked_nan2 = f16::NAN.to_bits() ^ NAN_MASK2; + assert!(f16::from_bits(masked_nan1).is_nan()); + assert!(f16::from_bits(masked_nan2).is_nan()); + + assert_eq!(f16::from_bits(masked_nan1).to_bits(), masked_nan1); + assert_eq!(f16::from_bits(masked_nan2).to_bits(), masked_nan2); +} + +#[test] +#[should_panic] +fn test_clamp_min_greater_than_max() { + let _ = 1.0f16.clamp(3.0, 1.0); +} + +#[test] +#[should_panic] +fn test_clamp_min_is_nan() { + let _ = 1.0f16.clamp(f16::NAN, 1.0); +} + +#[test] +#[should_panic] +fn test_clamp_max_is_nan() { + let _ = 1.0f16.clamp(3.0, f16::NAN); +} + +#[test] +fn test_total_cmp() { + use core::cmp::Ordering; + + fn quiet_bit_mask() -> u16 { + 1 << (f16::MANTISSA_DIGITS - 2) + } + + // FIXME(f16_f128): test subnormals when powf is available + // fn min_subnorm() -> f16 { + // f16::MIN_POSITIVE / f16::powf(2.0, f16::MANTISSA_DIGITS as f16 - 1.0) + // } + + // fn max_subnorm() -> f16 { + // f16::MIN_POSITIVE - min_subnorm() + // } + + fn q_nan() -> f16 { + f16::from_bits(f16::NAN.to_bits() | quiet_bit_mask()) + } + + fn s_nan() -> f16 { + f16::from_bits((f16::NAN.to_bits() & !quiet_bit_mask()) + 42) + } + + assert_eq!(Ordering::Equal, (-q_nan()).total_cmp(&-q_nan())); + assert_eq!(Ordering::Equal, (-s_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Equal, (-f16::INFINITY).total_cmp(&-f16::INFINITY)); + assert_eq!(Ordering::Equal, (-f16::MAX).total_cmp(&-f16::MAX)); + assert_eq!(Ordering::Equal, (-2.5_f16).total_cmp(&-2.5)); + assert_eq!(Ordering::Equal, (-1.0_f16).total_cmp(&-1.0)); + assert_eq!(Ordering::Equal, (-1.5_f16).total_cmp(&-1.5)); + assert_eq!(Ordering::Equal, (-0.5_f16).total_cmp(&-0.5)); + assert_eq!(Ordering::Equal, (-f16::MIN_POSITIVE).total_cmp(&-f16::MIN_POSITIVE)); + // assert_eq!(Ordering::Equal, (-max_subnorm()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Equal, (-min_subnorm()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Equal, (-0.0_f16).total_cmp(&-0.0)); + assert_eq!(Ordering::Equal, 0.0_f16.total_cmp(&0.0)); + // assert_eq!(Ordering::Equal, min_subnorm().total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Equal, max_subnorm().total_cmp(&max_subnorm())); + assert_eq!(Ordering::Equal, f16::MIN_POSITIVE.total_cmp(&f16::MIN_POSITIVE)); + assert_eq!(Ordering::Equal, 0.5_f16.total_cmp(&0.5)); + assert_eq!(Ordering::Equal, 1.0_f16.total_cmp(&1.0)); + assert_eq!(Ordering::Equal, 1.5_f16.total_cmp(&1.5)); + assert_eq!(Ordering::Equal, 2.5_f16.total_cmp(&2.5)); + assert_eq!(Ordering::Equal, f16::MAX.total_cmp(&f16::MAX)); + assert_eq!(Ordering::Equal, f16::INFINITY.total_cmp(&f16::INFINITY)); + assert_eq!(Ordering::Equal, s_nan().total_cmp(&s_nan())); + assert_eq!(Ordering::Equal, q_nan().total_cmp(&q_nan())); + + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f16::INFINITY)); + assert_eq!(Ordering::Less, (-f16::INFINITY).total_cmp(&-f16::MAX)); + assert_eq!(Ordering::Less, (-f16::MAX).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-2.5_f16).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-1.5_f16).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-1.0_f16).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-0.5_f16).total_cmp(&-f16::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-f16::MIN_POSITIVE).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-max_subnorm()).total_cmp(&-min_subnorm())); + // assert_eq!(Ordering::Less, (-min_subnorm()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-0.0_f16).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, 0.0_f16.total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, min_subnorm().total_cmp(&max_subnorm())); + // assert_eq!(Ordering::Less, max_subnorm().total_cmp(&f16::MIN_POSITIVE)); + assert_eq!(Ordering::Less, f16::MIN_POSITIVE.total_cmp(&0.5)); + assert_eq!(Ordering::Less, 0.5_f16.total_cmp(&1.0)); + assert_eq!(Ordering::Less, 1.0_f16.total_cmp(&1.5)); + assert_eq!(Ordering::Less, 1.5_f16.total_cmp(&2.5)); + assert_eq!(Ordering::Less, 2.5_f16.total_cmp(&f16::MAX)); + assert_eq!(Ordering::Less, f16::MAX.total_cmp(&f16::INFINITY)); + assert_eq!(Ordering::Less, f16::INFINITY.total_cmp(&s_nan())); + assert_eq!(Ordering::Less, s_nan().total_cmp(&q_nan())); + + assert_eq!(Ordering::Greater, (-s_nan()).total_cmp(&-q_nan())); + assert_eq!(Ordering::Greater, (-f16::INFINITY).total_cmp(&-s_nan())); + assert_eq!(Ordering::Greater, (-f16::MAX).total_cmp(&-f16::INFINITY)); + assert_eq!(Ordering::Greater, (-2.5_f16).total_cmp(&-f16::MAX)); + assert_eq!(Ordering::Greater, (-1.5_f16).total_cmp(&-2.5)); + assert_eq!(Ordering::Greater, (-1.0_f16).total_cmp(&-1.5)); + assert_eq!(Ordering::Greater, (-0.5_f16).total_cmp(&-1.0)); + assert_eq!(Ordering::Greater, (-f16::MIN_POSITIVE).total_cmp(&-0.5)); + // assert_eq!(Ordering::Greater, (-max_subnorm()).total_cmp(&-f16::MIN_POSITIVE)); + // assert_eq!(Ordering::Greater, (-min_subnorm()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Greater, (-0.0_f16).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Greater, 0.0_f16.total_cmp(&-0.0)); + // assert_eq!(Ordering::Greater, min_subnorm().total_cmp(&0.0)); + // assert_eq!(Ordering::Greater, max_subnorm().total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Greater, f16::MIN_POSITIVE.total_cmp(&max_subnorm())); + assert_eq!(Ordering::Greater, 0.5_f16.total_cmp(&f16::MIN_POSITIVE)); + assert_eq!(Ordering::Greater, 1.0_f16.total_cmp(&0.5)); + assert_eq!(Ordering::Greater, 1.5_f16.total_cmp(&1.0)); + assert_eq!(Ordering::Greater, 2.5_f16.total_cmp(&1.5)); + assert_eq!(Ordering::Greater, f16::MAX.total_cmp(&2.5)); + assert_eq!(Ordering::Greater, f16::INFINITY.total_cmp(&f16::MAX)); + assert_eq!(Ordering::Greater, s_nan().total_cmp(&f16::INFINITY)); + assert_eq!(Ordering::Greater, q_nan().total_cmp(&s_nan())); + + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-s_nan())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f16::INFINITY)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f16::MAX)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-f16::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&max_subnorm())); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f16::MIN_POSITIVE)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&0.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&1.0)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&1.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&2.5)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f16::MAX)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&f16::INFINITY)); + assert_eq!(Ordering::Less, (-q_nan()).total_cmp(&s_nan())); + + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f16::INFINITY)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f16::MAX)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-2.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-1.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-1.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-0.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-f16::MIN_POSITIVE)); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-max_subnorm())); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-min_subnorm())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&-0.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&0.0)); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&min_subnorm())); + // assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&max_subnorm())); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f16::MIN_POSITIVE)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&0.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&1.0)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&1.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&2.5)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f16::MAX)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&f16::INFINITY)); + assert_eq!(Ordering::Less, (-s_nan()).total_cmp(&s_nan())); +} diff --git a/library/std/src/f32/tests.rs b/library/std/src/f32/tests.rs index 9ca4e8f2f45fe..63e65698374c8 100644 --- a/library/std/src/f32/tests.rs +++ b/library/std/src/f32/tests.rs @@ -2,6 +2,45 @@ use crate::f32::consts; use crate::num::FpCategory as Fp; use crate::num::*; +/// Smallest number +#[allow(dead_code)] // unused on x86 +const TINY_BITS: u32 = 0x1; + +/// Next smallest number +#[allow(dead_code)] // unused on x86 +const TINY_UP_BITS: u32 = 0x2; + +/// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0 +#[allow(dead_code)] // unused on x86 +const MAX_DOWN_BITS: u32 = 0x7f7f_fffe; + +/// Zeroed exponent, full significant +#[allow(dead_code)] // unused on x86 +const LARGEST_SUBNORMAL_BITS: u32 = 0x007f_ffff; + +/// Exponent = 0b1, zeroed significand +#[allow(dead_code)] // unused on x86 +const SMALLEST_NORMAL_BITS: u32 = 0x0080_0000; + +/// First pattern over the mantissa +#[allow(dead_code)] // unused on x86 +const NAN_MASK1: u32 = 0x002a_aaaa; + +/// Second pattern over the mantissa +#[allow(dead_code)] // unused on x86 +const NAN_MASK2: u32 = 0x0055_5555; + +#[allow(unused_macros)] +macro_rules! assert_f32_biteq { + ($left : expr, $right : expr) => { + let l: &f32 = &$left; + let r: &f32 = &$right; + let lb = l.to_bits(); + let rb = r.to_bits(); + assert_eq!(lb, rb, "float {l} ({lb:#010x}) is not bitequal to {r} ({rb:#010x})"); + }; +} + #[test] fn test_num_f32() { test_num(10f32, 2f32); @@ -315,27 +354,16 @@ fn test_is_sign_negative() { assert!((-f32::NAN).is_sign_negative()); } -#[allow(unused_macros)] -macro_rules! assert_f32_biteq { - ($left : expr, $right : expr) => { - let l: &f32 = &$left; - let r: &f32 = &$right; - let lb = l.to_bits(); - let rb = r.to_bits(); - assert_eq!(lb, rb, "float {} ({:#x}) is not equal to {} ({:#x})", *l, lb, *r, rb); - }; -} - // Ignore test on x87 floating point, these platforms do not guarantee NaN // payloads are preserved and flush denormals to zero, failing the tests. #[cfg(not(target_arch = "x86"))] #[test] fn test_next_up() { - let tiny = f32::from_bits(1); - let tiny_up = f32::from_bits(2); - let max_down = f32::from_bits(0x7f7f_fffe); - let largest_subnormal = f32::from_bits(0x007f_ffff); - let smallest_normal = f32::from_bits(0x0080_0000); + let tiny = f32::from_bits(TINY_BITS); + let tiny_up = f32::from_bits(TINY_UP_BITS); + let max_down = f32::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f32::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f32::from_bits(SMALLEST_NORMAL_BITS); assert_f32_biteq!(f32::NEG_INFINITY.next_up(), f32::MIN); assert_f32_biteq!(f32::MIN.next_up(), -max_down); assert_f32_biteq!((-1.0 - f32::EPSILON).next_up(), -1.0); @@ -352,8 +380,8 @@ fn test_next_up() { // Check that NaNs roundtrip. let nan0 = f32::NAN; - let nan1 = f32::from_bits(f32::NAN.to_bits() ^ 0x002a_aaaa); - let nan2 = f32::from_bits(f32::NAN.to_bits() ^ 0x0055_5555); + let nan1 = f32::from_bits(f32::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f32::from_bits(f32::NAN.to_bits() ^ NAN_MASK2); assert_f32_biteq!(nan0.next_up(), nan0); assert_f32_biteq!(nan1.next_up(), nan1); assert_f32_biteq!(nan2.next_up(), nan2); @@ -364,11 +392,11 @@ fn test_next_up() { #[cfg(not(target_arch = "x86"))] #[test] fn test_next_down() { - let tiny = f32::from_bits(1); - let tiny_up = f32::from_bits(2); - let max_down = f32::from_bits(0x7f7f_fffe); - let largest_subnormal = f32::from_bits(0x007f_ffff); - let smallest_normal = f32::from_bits(0x0080_0000); + let tiny = f32::from_bits(TINY_BITS); + let tiny_up = f32::from_bits(TINY_UP_BITS); + let max_down = f32::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f32::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f32::from_bits(SMALLEST_NORMAL_BITS); assert_f32_biteq!(f32::NEG_INFINITY.next_down(), f32::NEG_INFINITY); assert_f32_biteq!(f32::MIN.next_down(), f32::NEG_INFINITY); assert_f32_biteq!((-max_down).next_down(), f32::MIN); @@ -386,8 +414,8 @@ fn test_next_down() { // Check that NaNs roundtrip. let nan0 = f32::NAN; - let nan1 = f32::from_bits(f32::NAN.to_bits() ^ 0x002a_aaaa); - let nan2 = f32::from_bits(f32::NAN.to_bits() ^ 0x0055_5555); + let nan1 = f32::from_bits(f32::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f32::from_bits(f32::NAN.to_bits() ^ NAN_MASK2); assert_f32_biteq!(nan0.next_down(), nan0); assert_f32_biteq!(nan1.next_down(), nan1); assert_f32_biteq!(nan2.next_down(), nan2); @@ -734,8 +762,8 @@ fn test_float_bits_conv() { // Check that NaNs roundtrip their bits regardless of signaling-ness // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits - let masked_nan1 = f32::NAN.to_bits() ^ 0x002A_AAAA; - let masked_nan2 = f32::NAN.to_bits() ^ 0x0055_5555; + let masked_nan1 = f32::NAN.to_bits() ^ NAN_MASK1; + let masked_nan2 = f32::NAN.to_bits() ^ NAN_MASK2; assert!(f32::from_bits(masked_nan1).is_nan()); assert!(f32::from_bits(masked_nan2).is_nan()); diff --git a/library/std/src/f64/tests.rs b/library/std/src/f64/tests.rs index f88d01593b5e4..d9e17fd601d2d 100644 --- a/library/std/src/f64/tests.rs +++ b/library/std/src/f64/tests.rs @@ -2,6 +2,45 @@ use crate::f64::consts; use crate::num::FpCategory as Fp; use crate::num::*; +/// Smallest number +#[allow(dead_code)] // unused on x86 +const TINY_BITS: u64 = 0x1; + +/// Next smallest number +#[allow(dead_code)] // unused on x86 +const TINY_UP_BITS: u64 = 0x2; + +/// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0 +#[allow(dead_code)] // unused on x86 +const MAX_DOWN_BITS: u64 = 0x7fef_ffff_ffff_fffe; + +/// Zeroed exponent, full significant +#[allow(dead_code)] // unused on x86 +const LARGEST_SUBNORMAL_BITS: u64 = 0x000f_ffff_ffff_ffff; + +/// Exponent = 0b1, zeroed significand +#[allow(dead_code)] // unused on x86 +const SMALLEST_NORMAL_BITS: u64 = 0x0010_0000_0000_0000; + +/// First pattern over the mantissa +#[allow(dead_code)] // unused on x86 +const NAN_MASK1: u64 = 0x000a_aaaa_aaaa_aaaa; + +/// Second pattern over the mantissa +#[allow(dead_code)] // unused on x86 +const NAN_MASK2: u64 = 0x0005_5555_5555_5555; + +#[allow(unused_macros)] +macro_rules! assert_f64_biteq { + ($left : expr, $right : expr) => { + let l: &f64 = &$left; + let r: &f64 = &$right; + let lb = l.to_bits(); + let rb = r.to_bits(); + assert_eq!(lb, rb, "float {l} ({lb:#018x}) is not bitequal to {r} ({rb:#018x})"); + }; +} + #[test] fn test_num_f64() { test_num(10f64, 2f64); @@ -305,27 +344,16 @@ fn test_is_sign_negative() { assert!((-f64::NAN).is_sign_negative()); } -#[allow(unused_macros)] -macro_rules! assert_f64_biteq { - ($left : expr, $right : expr) => { - let l: &f64 = &$left; - let r: &f64 = &$right; - let lb = l.to_bits(); - let rb = r.to_bits(); - assert_eq!(lb, rb, "float {} ({:#x}) is not equal to {} ({:#x})", *l, lb, *r, rb); - }; -} - // Ignore test on x87 floating point, these platforms do not guarantee NaN // payloads are preserved and flush denormals to zero, failing the tests. #[cfg(not(target_arch = "x86"))] #[test] fn test_next_up() { - let tiny = f64::from_bits(1); - let tiny_up = f64::from_bits(2); - let max_down = f64::from_bits(0x7fef_ffff_ffff_fffe); - let largest_subnormal = f64::from_bits(0x000f_ffff_ffff_ffff); - let smallest_normal = f64::from_bits(0x0010_0000_0000_0000); + let tiny = f64::from_bits(TINY_BITS); + let tiny_up = f64::from_bits(TINY_UP_BITS); + let max_down = f64::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f64::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f64::from_bits(SMALLEST_NORMAL_BITS); assert_f64_biteq!(f64::NEG_INFINITY.next_up(), f64::MIN); assert_f64_biteq!(f64::MIN.next_up(), -max_down); assert_f64_biteq!((-1.0 - f64::EPSILON).next_up(), -1.0); @@ -341,8 +369,8 @@ fn test_next_up() { assert_f64_biteq!(f64::INFINITY.next_up(), f64::INFINITY); let nan0 = f64::NAN; - let nan1 = f64::from_bits(f64::NAN.to_bits() ^ 0x000a_aaaa_aaaa_aaaa); - let nan2 = f64::from_bits(f64::NAN.to_bits() ^ 0x0005_5555_5555_5555); + let nan1 = f64::from_bits(f64::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f64::from_bits(f64::NAN.to_bits() ^ NAN_MASK2); assert_f64_biteq!(nan0.next_up(), nan0); assert_f64_biteq!(nan1.next_up(), nan1); assert_f64_biteq!(nan2.next_up(), nan2); @@ -353,11 +381,11 @@ fn test_next_up() { #[cfg(not(target_arch = "x86"))] #[test] fn test_next_down() { - let tiny = f64::from_bits(1); - let tiny_up = f64::from_bits(2); - let max_down = f64::from_bits(0x7fef_ffff_ffff_fffe); - let largest_subnormal = f64::from_bits(0x000f_ffff_ffff_ffff); - let smallest_normal = f64::from_bits(0x0010_0000_0000_0000); + let tiny = f64::from_bits(TINY_BITS); + let tiny_up = f64::from_bits(TINY_UP_BITS); + let max_down = f64::from_bits(MAX_DOWN_BITS); + let largest_subnormal = f64::from_bits(LARGEST_SUBNORMAL_BITS); + let smallest_normal = f64::from_bits(SMALLEST_NORMAL_BITS); assert_f64_biteq!(f64::NEG_INFINITY.next_down(), f64::NEG_INFINITY); assert_f64_biteq!(f64::MIN.next_down(), f64::NEG_INFINITY); assert_f64_biteq!((-max_down).next_down(), f64::MIN); @@ -374,8 +402,8 @@ fn test_next_down() { assert_f64_biteq!(f64::INFINITY.next_down(), f64::MAX); let nan0 = f64::NAN; - let nan1 = f64::from_bits(f64::NAN.to_bits() ^ 0x000a_aaaa_aaaa_aaaa); - let nan2 = f64::from_bits(f64::NAN.to_bits() ^ 0x0005_5555_5555_5555); + let nan1 = f64::from_bits(f64::NAN.to_bits() ^ NAN_MASK1); + let nan2 = f64::from_bits(f64::NAN.to_bits() ^ NAN_MASK2); assert_f64_biteq!(nan0.next_down(), nan0); assert_f64_biteq!(nan1.next_down(), nan1); assert_f64_biteq!(nan2.next_down(), nan2); @@ -715,9 +743,8 @@ fn test_float_bits_conv() { assert_approx_eq!(f64::from_bits(0xc02c800000000000), -14.25); // Check that NaNs roundtrip their bits regardless of signaling-ness - // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits - let masked_nan1 = f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA; - let masked_nan2 = f64::NAN.to_bits() ^ 0x0005_5555_5555_5555; + let masked_nan1 = f64::NAN.to_bits() ^ NAN_MASK1; + let masked_nan2 = f64::NAN.to_bits() ^ NAN_MASK2; assert!(f64::from_bits(masked_nan1).is_nan()); assert!(f64::from_bits(masked_nan2).is_nan()); diff --git a/library/std/src/macros.rs b/library/std/src/macros.rs index 58df83bd79d23..972b6015932db 100644 --- a/library/std/src/macros.rs +++ b/library/std/src/macros.rs @@ -373,10 +373,17 @@ macro_rules! dbg { }; } +/// Verify that floats are within a tolerance of each other, 1.0e-6 by default. #[cfg(test)] macro_rules! assert_approx_eq { - ($a:expr, $b:expr) => {{ + ($a:expr, $b:expr) => {{ assert_approx_eq!($a, $b, 1.0e-6) }}; + ($a:expr, $b:expr, $lim:expr) => {{ let (a, b) = (&$a, &$b); - assert!((*a - *b).abs() < 1.0e-6, "{} is not approximately equal to {}", *a, *b); + let diff = (*a - *b).abs(); + assert!( + diff < $lim, + "{a:?} is not approximately equal to {b:?} (threshold {lim:?}, actual {diff:?})", + lim = $lim + ); }}; }