StdLib/LibC/CRT/Ia32/ashrdi3.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2009 - 2011, Intel Corporation. All rights reserved.<BR>
   4 # This program and the accompanying materials are licensed and made available
   5 # under the terms and conditions of the BSD License which accompanies this
   6 # distribution.  The full text of the license may be found at
   7 # http://opensource.org/licenses/bsd-license.php.
   8 #
   9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 # Module Name:
  13 #
  14 #   MathRShiftU64.S
  15 #
  16 # Abstract:
  17 #
  18 #   64-bit Math Worker Function.
  19 #   Shifts a 64-bit unsigned value right by a certain number of bits.
  20 #
  21 #------------------------------------------------------------------------------
  22
  23
  24     .686:
  25     .code:
  26
  27 ASM_GLOBAL ASM_PFX(__ashrdi3)
  28
  29 #------------------------------------------------------------------------------
  30 #
  31 # void __cdecl __ashrdi3 (void)
  32 #
  33 #------------------------------------------------------------------------------
  34 ASM_PFX(__ashrdi3):
  35     #
  36     # Checking: Only handle 64bit shifting or more
  37     #
  38     cmpb    $64, %cl
  39     jae     _Exit
  40
  41     #
  42     # Handle shifting between 0 and 31 bits
  43     #
  44     cmpb    $32, %cl
  45     jae     More32
  46     shrd    %cl, %edx, %eax
  47     shr     %cl, %edx
  48     ret
  49
  50     #
  51     # Handle shifting of 32-63 bits
  52     #
  53 More32:
  54     movl    %edx, %eax
  55     xor     %edx, %edx
  56     and     $32, %cl
  57     shr     %cl, %eax
  58     ret
  59
  60     #
  61     # Invalid number (less then 32bits), return 0
  62     #
  63 _Exit:
  64     xor     %eax, %eax
  65     xor     %edx, %edx
  66     ret