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Merge pull request #380 from rust-lang/bitmask-order

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Fix bitmask vector bit order
This commit is contained in:
Caleb Zulawski 2024-01-29 14:08:44 -05:00 committed by GitHub
commit f55ca305a5
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2 changed files with 48 additions and 0 deletions
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6
crates/core_simd/src/masks/full_masks.rs
View File

@ -156,6 +156,9 @@ where
for x in bytes.as_mut() {
*x = x.reverse_bits()
}
if N % 8 > 0 {
bytes.as_mut()[N / 8] >>= 8 - N % 8;
}
}
bitmask.as_mut_array()[..bytes.as_ref().len()].copy_from_slice(bytes.as_ref());
@ -179,6 +182,9 @@ where
for x in bytes.as_mut() {
*x = x.reverse_bits();
}
if N % 8 > 0 {
bytes.as_mut()[N / 8] >>= 8 - N % 8;
}
}
// Compute the regular mask

42
crates/core_simd/tests/masks.rs
View File

@ -99,6 +99,19 @@ macro_rules! test_mask_api {
assert_eq!(Mask::<$type, 2>::from_bitmask(bitmask), mask);
}
#[cfg(feature = "all_lane_counts")]
#[test]
fn roundtrip_bitmask_conversion_odd() {
let values = [
true, false, true, false, true, true, false, false, false, true, true,
];
let mask = Mask::<$type, 11>::from_array(values);
let bitmask = mask.to_bitmask();
assert_eq!(bitmask, 0b11000110101);
assert_eq!(Mask::<$type, 11>::from_bitmask(bitmask), mask);
}
#[test]
fn cast() {
fn cast_impl<T: core_simd::simd::MaskElement>()
@ -134,6 +147,35 @@ macro_rules! test_mask_api {
assert_eq!(bitmask.resize::<2>(0).to_ne_bytes()[..2], [0b01001001, 0b10000011]);
assert_eq!(Mask::<$type, 16>::from_bitmask_vector(bitmask), mask);
}
// rust-lang/portable-simd#379
#[test]
fn roundtrip_bitmask_vector_conversion_small() {
use core_simd::simd::ToBytes;
let values = [
true, false, true, true
];
let mask = Mask::<$type, 4>::from_array(values);
let bitmask = mask.to_bitmask_vector();
assert_eq!(bitmask.resize::<1>(0).to_ne_bytes()[0], 0b00001101);
assert_eq!(Mask::<$type, 4>::from_bitmask_vector(bitmask), mask);
}
/* FIXME doesn't work with non-powers-of-two, yet
// rust-lang/portable-simd#379
#[cfg(feature = "all_lane_counts")]
#[test]
fn roundtrip_bitmask_vector_conversion_odd() {
use core_simd::simd::ToBytes;
let values = [
true, false, true, false, true, true, false, false, false, true, true,
];
let mask = Mask::<$type, 11>::from_array(values);
let bitmask = mask.to_bitmask_vector();
assert_eq!(bitmask.resize::<2>(0).to_ne_bytes()[..2], [0b00110101, 0b00000110]);
assert_eq!(Mask::<$type, 11>::from_bitmask_vector(bitmask), mask);
}
*/
}
}
}