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Change from_parts to take a u32 exponent rather than i32

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Make things more consistent with other API that works with a bitwise
representation of the exponent. That is, use `u32` when working with a
bitwise (biased) representation, use `i32` when the bitwise
representation has been adjusted for bias and ay be negative.

Every place this has been used so far has an `as i32`, so this change
makes things cleaner anyway.
This commit is contained in:
Trevor Gross 2025-01-23 09:15:43 +00:00 • committed by Trevor Gross
parent ca8dccc5b6
commit b8da1919f9
2 changed files with 9 additions and 9 deletions
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2
library/compiler-builtins/libm/src/math/generic/sqrt.rs
View file

@ -92,7 +92,7 @@ where
}
// Normalize subnormals by multiplying by 1.0 << SIG_BITS (e.g. 0x1p52 for doubles).
let scaled = x * F::from_parts(false, (F::SIG_BITS + F::EXP_BIAS) as i32, zero);
let scaled = x * F::from_parts(false, F::SIG_BITS + F::EXP_BIAS, zero);
ix = scaled.to_bits();
match top {
Exp::Shifted(ref mut v) => {

16
library/compiler-builtins/libm/src/math/support/float_traits.rs
View file

@ -131,11 +131,11 @@ pub trait Float:
fn from_bits(a: Self::Int) -> Self;
/// Constructs a `Self` from its parts. Inputs are treated as bits and shifted into position.
fn from_parts(negative: bool, exponent: i32, significand: Self::Int) -> Self {
fn from_parts(negative: bool, exponent: u32, significand: Self::Int) -> Self {
let sign = if negative { Self::Int::ONE } else { Self::Int::ZERO };
Self::from_bits(
(sign << (Self::BITS - 1))
| (Self::Int::cast_from(exponent as u32 & Self::EXP_MAX) << Self::SIG_BITS)
| (Self::Int::cast_from(exponent & Self::EXP_MAX) << Self::SIG_BITS)
| (significand & Self::SIG_MASK),
)
}
@ -282,7 +282,7 @@ mod tests {
assert_eq!(f16::from_bits(0x1).exp_unbiased(), -15);
// `from_parts`
assert_biteq!(f16::from_parts(true, f16::EXP_BIAS as i32, 0), -1.0f16);
assert_biteq!(f16::from_parts(true, f16::EXP_BIAS, 0), -1.0f16);
assert_biteq!(f16::from_parts(false, 0, 1), f16::from_bits(0x1));
}
@ -304,8 +304,8 @@ mod tests {
assert_eq!(f32::from_bits(0x1).exp_unbiased(), -127);
// `from_parts`
assert_biteq!(f32::from_parts(true, f32::EXP_BIAS as i32, 0), -1.0f32);
assert_biteq!(f32::from_parts(false, 10 + f32::EXP_BIAS as i32, 0), hf32!("0x1p10"));
assert_biteq!(f32::from_parts(true, f32::EXP_BIAS, 0), -1.0f32);
assert_biteq!(f32::from_parts(false, 10 + f32::EXP_BIAS, 0), hf32!("0x1p10"));
assert_biteq!(f32::from_parts(false, 0, 1), f32::from_bits(0x1));
}
@ -327,8 +327,8 @@ mod tests {
assert_eq!(f64::from_bits(0x1).exp_unbiased(), -1023);
// `from_parts`
assert_biteq!(f64::from_parts(true, f64::EXP_BIAS as i32, 0), -1.0f64);
assert_biteq!(f64::from_parts(false, 10 + f64::EXP_BIAS as i32, 0), hf64!("0x1p10"));
assert_biteq!(f64::from_parts(true, f64::EXP_BIAS, 0), -1.0f64);
assert_biteq!(f64::from_parts(false, 10 + f64::EXP_BIAS, 0), hf64!("0x1p10"));
assert_biteq!(f64::from_parts(false, 0, 1), f64::from_bits(0x1));
}
@ -351,7 +351,7 @@ mod tests {
assert_eq!(f128::from_bits(0x1).exp_unbiased(), -16383);
// `from_parts`
assert_biteq!(f128::from_parts(true, f128::EXP_BIAS as i32, 0), -1.0f128);
assert_biteq!(f128::from_parts(true, f128::EXP_BIAS, 0), -1.0f128);
assert_biteq!(f128::from_parts(false, 0, 1), f128::from_bits(0x1));
}
}