diff --git a/src/float/add.rs b/src/float/add.rs index 7c9f11a..7707850 100644 --- a/src/float/add.rs +++ b/src/float/add.rs @@ -9,27 +9,27 @@ macro_rules! add { #[allow(unused_parens)] #[cfg_attr(not(test), no_mangle)] pub extern fn $intrinsic(a: $ty, b: $ty) -> $ty { - let one = Wrapping(1 as <$ty as Float>::Int); - let zero = Wrapping(0 as <$ty as Float>::Int); + let one = Wrapping(1 as <$ty as Float>::Int); + let zero = Wrapping(0 as <$ty as Float>::Int); - let bits = Wrapping(<$ty>::bits() as <$ty as Float>::Int); - let significand_bits = Wrapping(<$ty>::significand_bits() as <$ty as Float>::Int); - let exponent_bits = Wrapping(<$ty>::exponent_bits() as <$ty as Float>::Int); - let max_exponent = (one << exponent_bits.0 as usize) - one; + let bits = Wrapping(<$ty>::bits() as <$ty as Float>::Int); + let significand_bits = Wrapping(<$ty>::significand_bits() as <$ty as Float>::Int); + let exponent_bits = bits - significand_bits - one; + let max_exponent = (one << exponent_bits.0 as usize) - one; - let implicit_bit = one << significand_bits.0 as usize; - let significand_mask = implicit_bit - one; - let sign_bit = one << (significand_bits + exponent_bits).0 as usize; - let abs_mask = sign_bit - one; - let exponent_mask = abs_mask ^ significand_mask; - let inf_rep = exponent_mask; - let quiet_bit = implicit_bit >> 1; - let qnan_rep = exponent_mask | quiet_bit; + let implicit_bit = one << significand_bits.0 as usize; + let significand_mask = implicit_bit - one; + let sign_bit = one << (significand_bits + exponent_bits).0 as usize; + let abs_mask = sign_bit - one; + let exponent_mask = abs_mask ^ significand_mask; + let inf_rep = exponent_mask; + let quiet_bit = implicit_bit >> 1; + let qnan_rep = exponent_mask | quiet_bit; - let mut a_rep = Wrapping(a.repr()); - let mut b_rep = Wrapping(b.repr()); - let a_abs = a_rep & abs_mask; - let b_abs = b_rep & abs_mask; + let mut a_rep = Wrapping(a.repr()); + let mut b_rep = Wrapping(b.repr()); + let a_abs = a_rep & abs_mask; + let b_abs = b_rep & abs_mask; // Detect if a or b is zero, infinity, or NaN. if a_abs - one >= inf_rep - one || @@ -188,7 +188,7 @@ mod tests { use core::{f32, f64}; use float::Float; - use qc::{F32, F64}; + use qc::{U32, U64}; // NOTE The tests below have special handing for NaN values. // Because NaN != NaN, the floating-point representations must be used @@ -212,18 +212,107 @@ mod tests { } } + // TODO: Add F32/F64 to qc so that they print the right values (at the very least) check! { fn __addsf3(f: extern fn(f32, f32) -> f32, - a: F32, - b: F32) + a: U32, + b: U32) -> Option > { - Some(FRepr(f(a.0, b.0))) + let (a, b) = (f32::from_repr(a.0), f32::from_repr(b.0)); + Some(FRepr(f(a, b))) } fn __adddf3(f: extern fn(f64, f64) -> f64, - a: F64, - b: F64) -> Option > { - Some(FRepr(f(a.0, b.0))) + a: U64, + b: U64) -> Option > { + let (a, b) = (f64::from_repr(a.0), f64::from_repr(b.0)); + Some(FRepr(f(a, b))) } } + + // More tests for special float values + + #[test] + fn test_float_tiny_plus_tiny() { + let tiny = f32::from_repr(1); + let r = super::__addsf3(tiny, tiny); + assert!(r.eq_repr(tiny + tiny)); + } + + #[test] + fn test_double_tiny_plus_tiny() { + let tiny = f64::from_repr(1); + let r = super::__adddf3(tiny, tiny); + assert!(r.eq_repr(tiny + tiny)); + } + + #[test] + fn test_float_small_plus_small() { + let a = f32::from_repr(327); + let b = f32::from_repr(256); + let r = super::__addsf3(a, b); + assert!(r.eq_repr(a + b)); + } + + #[test] + fn test_double_small_plus_small() { + let a = f64::from_repr(327); + let b = f64::from_repr(256); + let r = super::__adddf3(a, b); + assert!(r.eq_repr(a + b)); + } + + #[test] + fn test_float_one_plus_one() { + let r = super::__addsf3(1f32, 1f32); + assert!(r.eq_repr(1f32 + 1f32)); + } + + #[test] + fn test_double_one_plus_one() { + let r = super::__adddf3(1f64, 1f64); + assert!(r.eq_repr(1f64 + 1f64)); + } + + #[test] + fn test_float_different_nan() { + let a = f32::from_repr(1); + let b = f32::from_repr(0b11111111100100010001001010101010); + let x = super::__addsf3(a, b); + let y = a + b; + assert!(x.eq_repr(y)); + } + + #[test] + fn test_double_different_nan() { + let a = f64::from_repr(1); + let b = f64::from_repr(0b1111111111110010001000100101010101001000101010000110100011101011); + let x = super::__adddf3(a, b); + let y = a + b; + assert!(x.eq_repr(y)); + } + + #[test] + fn test_float_nan() { + let r = super::__addsf3(f32::NAN, 1.23); + assert_eq!(r.repr(), f32::NAN.repr()); + } + + #[test] + fn test_double_nan() { + let r = super::__adddf3(f64::NAN, 1.23); + assert_eq!(r.repr(), f64::NAN.repr()); + } + + #[test] + fn test_float_inf() { + let r = super::__addsf3(f32::INFINITY, -123.4); + assert_eq!(r, f32::INFINITY); + } + + #[test] + fn test_double_inf() { + let r = super::__adddf3(f64::INFINITY, -123.4); + assert_eq!(r, f64::INFINITY); + } } diff --git a/src/float/mod.rs b/src/float/mod.rs index 8aa6328..cee2b73 100644 --- a/src/float/mod.rs +++ b/src/float/mod.rs @@ -10,45 +10,21 @@ pub trait Float: Sized + Copy { /// Returns the bitwidth of the float type fn bits() -> u32; - /// Returns the bitwidth of the exponent - fn exponent_bits() -> u32; - /// Returns the bitwidth of the significand fn significand_bits() -> u32; - /// Returns a mask for the sign bit of `self` - fn sign_mask() -> Self::Int; - - /// Returns a mask for the exponent portion of `self` - fn exponent_mask() -> Self::Int; - - /// Returns a mask for the significand portion of `self` - fn significand_mask() -> Self::Int; - - /// Returns the sign bit of `self` - fn sign(self) -> bool; - - /// Returns the exponent portion of `self`, shifted to the right - fn exponent(self) -> Self::Int; - - /// Returns the significand portion of `self` - fn significand(self) -> Self::Int; - /// Returns `self` transmuted to `Self::Int` fn repr(self) -> Self::Int; #[cfg(test)] /// Checks if two floats have the same bit representation. *Except* for NaNs! NaN can be - /// represented in multiple different ways. This method returns `true` if two NaNs are + /// represented in multiple different ways. This methods returns `true` if two NaNs are /// compared. fn eq_repr(self, rhs: Self) -> bool; /// Returns a `Self::Int` transmuted back to `Self` fn from_repr(a: Self::Int) -> Self; - /// Constructs a `Self` from its parts - fn from_parts(sign: bool, exponent: Self::Int, significand: Self::Int) -> Self; - /// Returns (normalized exponent, normalized significand) fn normalize(significand: Self::Int) -> (i32, Self::Int); } @@ -58,21 +34,9 @@ impl Float for f32 { fn bits() -> u32 { 32 } - fn exponent_bits() -> u32 { - 8 - } fn significand_bits() -> u32 { 23 } - fn sign_mask() -> Self::Int { - 1 << (Self::bits() - 1) - } - fn exponent_mask() -> Self::Int { - ((1 << Self::exponent_bits()) - 1) << Self::significand_bits() - } - fn significand_mask() -> Self::Int { - (1 << Self::significand_bits()) - 1 - } fn repr(self) -> Self::Int { unsafe { mem::transmute(self) } } @@ -87,21 +51,6 @@ impl Float for f32 { fn from_repr(a: Self::Int) -> Self { unsafe { mem::transmute(a) } } - - fn from_parts(sign: bool, exponent: Self::Int, significand: Self::Int) -> Self { - Self::from_repr(((sign as Self::Int) << (Self::bits() - 1)) | - exponent & Self::exponent_mask() | - significand & Self::significand_mask()) - } - fn sign(self) -> bool { - (self.repr() & Self::sign_mask()) != 0 - } - fn exponent(self) -> Self::Int { - self.repr() >> Self::significand_bits() & Self::exponent_mask() - } - fn significand(self) -> Self::Int { - self.repr() & Self::significand_mask() - } fn normalize(significand: Self::Int) -> (i32, Self::Int) { let shift = significand.leading_zeros() .wrapping_sub((1u32 << Self::significand_bits()).leading_zeros()); @@ -113,21 +62,9 @@ impl Float for f64 { fn bits() -> u32 { 64 } - fn exponent_bits() -> u32 { - 11 - } fn significand_bits() -> u32 { 52 } - fn sign_mask() -> Self::Int { - 1 << (Self::bits() - 1) - } - fn exponent_mask() -> Self::Int { - ((1 << Self::exponent_bits()) - 1) << Self::significand_bits() - } - fn significand_mask() -> Self::Int { - (1 << Self::significand_bits()) - 1 - } fn repr(self) -> Self::Int { unsafe { mem::transmute(self) } } @@ -142,20 +79,6 @@ impl Float for f64 { fn from_repr(a: Self::Int) -> Self { unsafe { mem::transmute(a) } } - fn from_parts(sign: bool, exponent: Self::Int, significand: Self::Int) -> Self { - Self::from_repr(((sign as Self::Int) << (Self::bits() - 1)) | - exponent & Self::exponent_mask() | - significand & Self::significand_mask()) - } - fn sign(self) -> bool { - (self.repr() & Self::sign_mask()) != 0 - } - fn exponent(self) -> Self::Int { - self.repr() >> Self::significand_bits() & Self::exponent_mask() - } - fn significand(self) -> Self::Int { - self.repr() & Self::significand_mask() - } fn normalize(significand: Self::Int) -> (i32, Self::Int) { let shift = significand.leading_zeros() .wrapping_sub((1u64 << Self::significand_bits()).leading_zeros()); diff --git a/src/qc.rs b/src/qc.rs index 9d4fff3..1450a4e 100644 --- a/src/qc.rs +++ b/src/qc.rs @@ -5,12 +5,10 @@ use std::boxed::Box; use std::fmt; -use core::{f32, f64}; use quickcheck::{Arbitrary, Gen}; use int::LargeInt; -use float::Float; // Generates values in the full range of the integer type macro_rules! arbitrary { @@ -73,7 +71,6 @@ macro_rules! arbitrary { arbitrary!(I32: i32); arbitrary!(U32: u32); - // These integers are "too large". If we generate e.g. `u64` values in the full range then there's // only `1 / 2^32` chance of seeing a value smaller than `2^32` (i.e. whose higher "word" (32-bits) // is `0`)! But this is an important group of values to tests because we have special code paths for @@ -146,57 +143,6 @@ macro_rules! arbitrary_large { arbitrary_large!(I64: i64); arbitrary_large!(U64: u64); - -macro_rules! arbitrary_float { - ($TY:ident : $ty:ident) => { - #[derive(Clone, Copy)] - pub struct $TY(pub $ty); - - impl Arbitrary for $TY { - fn arbitrary(g: &mut G) -> $TY - where G: Gen - { - let special = [ - -0.0, 0.0, $ty::NAN, $ty::INFINITY, -$ty::INFINITY - ]; - - if g.gen_weighted_bool(10) { // Random special case - $TY(*g.choose(&special).unwrap()) - } else if g.gen_weighted_bool(10) { // NaN variants - let sign: bool = g.gen(); - let exponent: <$ty as Float>::Int = g.gen(); - let significand: <$ty as Float>::Int = 0; - $TY($ty::from_parts(sign, exponent, significand)) - } else if g.gen() { // Denormalized - let sign: bool = g.gen(); - let exponent: <$ty as Float>::Int = 0; - let significand: <$ty as Float>::Int = g.gen(); - $TY($ty::from_parts(sign, exponent, significand)) - } else { // Random anything - let sign: bool = g.gen(); - let exponent: <$ty as Float>::Int = g.gen(); - let significand: <$ty as Float>::Int = g.gen(); - $TY($ty::from_parts(sign, exponent, significand)) - } - } - - fn shrink(&self) -> Box> { - ::quickcheck::empty_shrinker() - } - } - - impl fmt::Debug for $TY { - fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { - fmt::Debug::fmt(&self.0, f) - } - } - } -} - -arbitrary_float!(F32: f32); -arbitrary_float!(F64: f64); - - // Convenience macro to test intrinsics against their reference implementations. // // Each intrinsic is tested against both the `gcc_s` library as well as @@ -317,4 +263,3 @@ macro_rules! check { } ) } -