MdePkg/Library/BaseLib/Ia32/RShiftU64.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
   4 # 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.S
  15 #
  16 # Abstract:
  17 #
  18 #   64-bit logical right shift function for IA-32
  19 #
  20 #------------------------------------------------------------------------------
  21
  22
  23     .code:
  24
  25 ASM_GLOBAL ASM_PFX(InternalMathRShiftU64)
  26
  27 #------------------------------------------------------------------------------
  28 # UINT64
  29 # EFIAPI
  30 # InternalMathRShiftU64 (
  31 #   IN      UINT64                    Operand,
  32 #   IN      UINTN                     Count
  33 #   );
  34 #------------------------------------------------------------------------------
  35 ASM_PFX(InternalMathRShiftU64):
  36     movb    12(%esp), %cl               # cl <- Count
  37     xorl    %edx, %edx
  38     movl    8(%esp), %eax
  39     testb   $32, %cl                    # Count >= 32?
  40     jnz     L0
  41     movl    %eax, %edx
  42     movl    0x4(%esp), %eax
  43 L0:
  44     shrdl   %cl, %edx, %eax
  45     shr     %cl, %edx
  46     ret