libgo/go/runtime/internal/sys/intrinsics.go

   1 // Copyright 2016 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package sys
   6
   7 //extern __builtin_ctz
   8 func builtinCtz32(uint32) int32
   9
  10 //extern __builtin_ctzll
  11 func builtinCtz64(uint64) int32
  12
  13 //go:nosplit
  14
  15 // Ctz64 counts trailing (low-order) zeroes,
  16 // and if all are zero, then 64.
  17 func Ctz64(x uint64) int {
  18         if x == 0 {
  19                 return 64
  20         }
  21         return int(builtinCtz64(x))
  22 }
  23
  24 //go:nosplit
  25
  26 // Ctz32 counts trailing (low-order) zeroes,
  27 // and if all are zero, then 32.
  28 func Ctz32(x uint32) int {
  29         if x == 0 {
  30                 return 32
  31         }
  32         return int(builtinCtz32(x))
  33 }
  34
  35 //extern __builtin_bswap64
  36 func bswap64(uint64) uint64
  37
  38 //go:nosplit
  39
  40 // Bswap64 returns its input with byte order reversed
  41 // 0x0102030405060708 -> 0x0807060504030201
  42 func Bswap64(x uint64) uint64 {
  43         return bswap64(x)
  44 }
  45
  46 //extern __builtin_bswap32
  47 func bswap32(uint32) uint32
  48
  49 //go:nosplit
  50
  51 // Bswap32 returns its input with byte order reversed
  52 // 0x01020304 -> 0x04030201
  53 func Bswap32(x uint32) uint32 {
  54         return bswap32(x)
  55 }