lib/rtl/i386/rtlswap.S

   1 /*
   2  * COPYRIGHT:         See COPYING in the top level directory
   3  * PROJECT:           ReactOS Run-Time Library
   4  * PURPOSE:           Byte swap functions
   5  * FILE:              lib/rtl/i386/rtlswap.S
   6  * PROGRAMER:         Alex Ionescu (alex.ionescu@reactos.org)
   7  */
   8
   9 .intel_syntax noprefix
  10
  11 .globl @RtlUshortByteSwap@4
  12 .globl @RtlUlongByteSwap@4
  13 .globl @RtlUlonglongByteSwap@8
  14
  15 /* FUNCTIONS ***************************************************************/
  16
  17 .func @RtlUshortByteSwap@4, @RtlUshortByteSwap@4
  18 @RtlUshortByteSwap@4:
  19
  20     /* Swap high and low bits */
  21     mov ah, cl
  22     mov al, ch
  23     ret
  24 .endfunc
  25
  26 .func @RtlUlongByteSwap@4, @RtlUlongByteSwap@4
  27 @RtlUlongByteSwap@4:
  28
  29     /* Swap high and low bits */
  30     mov eax, ecx
  31     bswap eax
  32     ret
  33 .endfunc
  34
  35 .func @RtlUlonglongByteSwap@8, @RtlUlonglongByteSwap@8
  36 @RtlUlonglongByteSwap@8:
  37
  38     /* Get 64-bit integer */
  39     mov edx, [esp+8]
  40     mov eax, [esp+4]
  41
  42     /* Swap it */
  43     bswap edx
  44     bswap eax
  45
  46     /* Return it */
  47     mov ecx, eax
  48     mov eax, edx
  49     mov edx, ecx
  50     ret
  51 .endfunc
  52
  53