diff options
Diffstat (limited to 'third_party/rust/packed_simd/src/api/swap_bytes.rs')
| -rw-r--r-- | third_party/rust/packed_simd/src/api/swap_bytes.rs | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/third_party/rust/packed_simd/src/api/swap_bytes.rs b/third_party/rust/packed_simd/src/api/swap_bytes.rs new file mode 100644 index 0000000000..4649ed679b --- /dev/null +++ b/third_party/rust/packed_simd/src/api/swap_bytes.rs @@ -0,0 +1,192 @@ +//! Horizontal swap bytes + +macro_rules! impl_swap_bytes { + ([$elem_ty:ident; $elem_count:expr]: $id:ident | $test_tt:tt) => { + impl $id { + /// Reverses the byte order of the vector. + #[inline] + pub fn swap_bytes(self) -> Self { + super::codegen::swap_bytes::SwapBytes::swap_bytes(self) + } + + /// Converts self to little endian from the target's endianness. + /// + /// On little endian this is a no-op. On big endian the bytes are + /// swapped. + #[inline] + pub fn to_le(self) -> Self { + #[cfg(target_endian = "little")] + { + self + } + #[cfg(not(target_endian = "little"))] + { + self.swap_bytes() + } + } + + /// Converts self to big endian from the target's endianness. + /// + /// On big endian this is a no-op. On little endian the bytes are + /// swapped. + #[inline] + pub fn to_be(self) -> Self { + #[cfg(target_endian = "big")] + { + self + } + #[cfg(not(target_endian = "big"))] + { + self.swap_bytes() + } + } + + /// Converts a vector from little endian to the target's endianness. + /// + /// On little endian this is a no-op. On big endian the bytes are + /// swapped. + #[inline] + pub fn from_le(x: Self) -> Self { + #[cfg(target_endian = "little")] + { + x + } + #[cfg(not(target_endian = "little"))] + { + x.swap_bytes() + } + } + + /// Converts a vector from big endian to the target's endianness. + /// + /// On big endian this is a no-op. On little endian the bytes are + /// swapped. + #[inline] + pub fn from_be(x: Self) -> Self { + #[cfg(target_endian = "big")] + { + x + } + #[cfg(not(target_endian = "big"))] + { + x.swap_bytes() + } + } + } + + test_if! { + $test_tt: + paste::item! { + pub mod [<$id _swap_bytes>] { + use super::*; + + const BYTES: [u8; 64] = [ + 0, 1, 2, 3, 4, 5, 6, 7, + 8, 9, 10, 11, 12, 13, 14, 15, + 16, 17, 18, 19, 20, 21, 22, 23, + 24, 25, 26, 27, 28, 29, 30, 31, + 32, 33, 34, 35, 36, 37, 38, 39, + 40, 41, 42, 43, 44, 45, 46, 47, + 48, 49, 50, 51, 52, 53, 54, 55, + 56, 57, 58, 59, 60, 61, 62, 63, + ]; + + macro_rules! swap { + ($func: ident) => {{ + // catch possible future >512 vectors + assert!(mem::size_of::<$id>() <= 64); + + let mut actual = BYTES; + let elems: &mut [$elem_ty] = unsafe { + slice::from_raw_parts_mut( + actual.as_mut_ptr() as *mut $elem_ty, + $id::lanes(), + ) + }; + + let vec = $id::from_slice_unaligned(elems); + $id::$func(vec).write_to_slice_unaligned(elems); + + actual + }}; + } + + macro_rules! test_swap { + ($func: ident) => {{ + let actual = swap!($func); + let expected = + BYTES.iter().rev() + .skip(64 - crate::mem::size_of::<$id>()); + assert!(actual.iter().zip(expected) + .all(|(x, y)| x == y)); + }}; + } + + macro_rules! test_no_swap { + ($func: ident) => {{ + let actual = swap!($func); + let expected = BYTES.iter() + .take(mem::size_of::<$id>()); + + assert!(actual.iter().zip(expected) + .all(|(x, y)| x == y)); + }}; + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn swap_bytes() { + test_swap!(swap_bytes); + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn to_le() { + #[cfg(target_endian = "little")] + { + test_no_swap!(to_le); + } + #[cfg(not(target_endian = "little"))] + { + test_swap!(to_le); + } + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn to_be() { + #[cfg(target_endian = "big")] + { + test_no_swap!(to_be); + } + #[cfg(not(target_endian = "big"))] + { + test_swap!(to_be); + } + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn from_le() { + #[cfg(target_endian = "little")] + { + test_no_swap!(from_le); + } + #[cfg(not(target_endian = "little"))] + { + test_swap!(from_le); + } + } + + #[cfg_attr(not(target_arch = "wasm32"), test)] #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)] + fn from_be() { + #[cfg(target_endian = "big")] + { + test_no_swap!(from_be); + } + #[cfg(not(target_endian = "big"))] + { + test_swap!(from_be); + } + } + } + } + } + }; +} |