MdePkg/Library/BaseLib/Ia32/RShiftU64.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006, Intel Corporation
   4 ; All rights reserved. This program and the accompanying materials
   5 ; are licensed and made available under the terms and conditions of the BSD License
   6 ; which accompanies this 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 ;   RShiftU64.asm
  15 ;
  16 ; Abstract:
  17 ;
  18 ;   64-bit logical right shift function for IA-32
  19 ;
  20 ;------------------------------------------------------------------------------
  21
  22     .686
  23     .model  flat,C
  24     .code
  25
  26 ;------------------------------------------------------------------------------
  27 ; UINT64
  28 ; EFIAPI
  29 ; InternalMathRShiftU64 (
  30 ;   IN      UINT64                    Operand,
  31 ;   IN      UINTN                     Count
  32 ;   );
  33 ;------------------------------------------------------------------------------
  34 InternalMathRShiftU64   PROC
  35     mov     cl, [esp + 12]              ; cl <- Count
  36     xor     edx, edx
  37     mov     eax, [esp + 8]
  38     test    cl, 32                      ; Count >= 32?
  39     cmovz   edx, eax
  40     cmovz   eax, [esp + 4]
  41     shrd    eax, edx, cl
  42     shr     edx, cl
  43     ret
  44 InternalMathRShiftU64   ENDP
  45
  46     END