vendor/packed_simd/src/codegen/swap_bytes.rs

   1 //! Horizontal swap bytes reductions.
   2
   3 // FIXME: investigate using `llvm.bswap`
   4 // https://github.com/rust-lang-nursery/packed_simd/issues/19
   5
   6 use crate::*;
   7
   8 pub(crate) trait SwapBytes {
   9     fn swap_bytes(self) -> Self;
  10 }
  11
  12 macro_rules! impl_swap_bytes {
  13     (v16: $($id:ident,)+) => {
  14         $(
  15             impl SwapBytes for $id {
  16                 #[inline]
  17                 fn swap_bytes(self) -> Self {
  18                     shuffle!(self, [1, 0])
  19                 }
  20             }
  21         )+
  22     };
  23     (v32: $($id:ident,)+) => {
  24         $(
  25             impl SwapBytes for $id {
  26                 #[inline]
  27                 #[allow(clippy::useless_transmute)]
  28                 fn swap_bytes(self) -> Self {
  29                     unsafe {
  30                         let bytes: u8x4 = crate::mem::transmute(self);
  31                         let result: u8x4 = shuffle!(bytes, [3, 2, 1, 0]);
  32                         crate::mem::transmute(result)
  33                     }
  34                 }
  35             }
  36         )+
  37     };
  38     (v64: $($id:ident,)+) => {
  39         $(
  40             impl SwapBytes for $id {
  41                 #[inline]
  42                 #[allow(clippy::useless_transmute)]
  43                 fn swap_bytes(self) -> Self {
  44                     unsafe {
  45                         let bytes: u8x8 = crate::mem::transmute(self);
  46                         let result: u8x8 = shuffle!(
  47                             bytes, [7, 6, 5, 4, 3, 2, 1, 0]
  48                         );
  49                         crate::mem::transmute(result)
  50                     }
  51                 }
  52             }
  53         )+
  54     };
  55     (v128: $($id:ident,)+) => {
  56         $(
  57             impl SwapBytes for $id {
  58                 #[inline]
  59                 #[allow(clippy::useless_transmute)]
  60                 fn swap_bytes(self) -> Self {
  61                     unsafe {
  62                         let bytes: u8x16 = crate::mem::transmute(self);
  63                         let result: u8x16 = shuffle!(bytes, [
  64                             15, 14, 13, 12, 11, 10, 9, 8,
  65                             7, 6, 5, 4, 3, 2, 1, 0
  66                         ]);
  67                         crate::mem::transmute(result)
  68                     }
  69                 }
  70             }
  71         )+
  72     };
  73     (v256: $($id:ident,)+) => {
  74         $(
  75             impl SwapBytes for $id {
  76                 #[inline]
  77                 #[allow(clippy::useless_transmute)]
  78                 fn swap_bytes(self) -> Self {
  79                     unsafe {
  80                         let bytes: u8x32 = crate::mem::transmute(self);
  81                         let result: u8x32 = shuffle!(bytes, [
  82                             31, 30, 29, 28, 27, 26, 25, 24,
  83                             23, 22, 21, 20, 19, 18, 17, 16,
  84                             15, 14, 13, 12, 11, 10, 9,  8,
  85                             7,  6,  5,  4,  3,  2,  1,  0
  86                         ]);
  87                         crate::mem::transmute(result)
  88                     }
  89                 }
  90             }
  91         )+
  92     };
  93     (v512: $($id:ident,)+) => {
  94         $(
  95             impl SwapBytes for $id {
  96                 #[inline]
  97                 #[allow(clippy::useless_transmute)]
  98                 fn swap_bytes(self) -> Self {
  99                     unsafe {
 100                         let bytes: u8x64 = crate::mem::transmute(self);
 101                         let result: u8x64 = shuffle!(bytes, [
 102                             63, 62, 61, 60, 59, 58, 57, 56,
 103                             55, 54, 53, 52, 51, 50, 49, 48,
 104                             47, 46, 45, 44, 43, 42, 41, 40,
 105                             39, 38, 37, 36, 35, 34, 33, 32,
 106                             31, 30, 29, 28, 27, 26, 25, 24,
 107                             23, 22, 21, 20, 19, 18, 17, 16,
 108                             15, 14, 13, 12, 11, 10, 9,  8,
 109                             7,  6,  5,  4,  3,  2,  1,  0
 110                         ]);
 111                         crate::mem::transmute(result)
 112                     }
 113                 }
 114             }
 115         )+
 116     };
 117 }
 118
 119 impl_swap_bytes!(v16: u8x2, i8x2,);
 120 impl_swap_bytes!(v32: u8x4, i8x4, u16x2, i16x2,);
 121 // FIXME: 64-bit single element vector
 122 impl_swap_bytes!(v64: u8x8, i8x8, u16x4, i16x4, u32x2, i32x2 /* u64x1, i64x1, */,);
 123
 124 impl_swap_bytes!(v128: u8x16, i8x16, u16x8, i16x8, u32x4, i32x4, u64x2, i64x2, u128x1, i128x1,);
 125 impl_swap_bytes!(v256: u8x32, i8x32, u16x16, i16x16, u32x8, i32x8, u64x4, i64x4, u128x2, i128x2,);
 126
 127 impl_swap_bytes!(v512: u8x64, i8x64, u16x32, i16x32, u32x16, i32x16, u64x8, i64x8, u128x4, i128x4,);
 128
 129 cfg_if! {
 130     if #[cfg(target_pointer_width = "8")] {
 131         impl_swap_bytes!(v16: isizex2, usizex2,);
 132         impl_swap_bytes!(v32: isizex4, usizex4,);
 133         impl_swap_bytes!(v64: isizex8, usizex8,);
 134     } else if #[cfg(target_pointer_width = "16")] {
 135         impl_swap_bytes!(v32: isizex2, usizex2,);
 136         impl_swap_bytes!(v64: isizex4, usizex4,);
 137         impl_swap_bytes!(v128: isizex8, usizex8,);
 138     } else if #[cfg(target_pointer_width = "32")] {
 139         impl_swap_bytes!(v64: isizex2, usizex2,);
 140         impl_swap_bytes!(v128: isizex4, usizex4,);
 141         impl_swap_bytes!(v256: isizex8, usizex8,);
 142     } else if #[cfg(target_pointer_width = "64")] {
 143         impl_swap_bytes!(v128: isizex2, usizex2,);
 144         impl_swap_bytes!(v256: isizex4, usizex4,);
 145         impl_swap_bytes!(v512: isizex8, usizex8,);
 146     } else {
 147         compile_error!("unsupported target_pointer_width");
 148     }
 149 }