MdePkg/BaseLib: Support IA32 processors without CMOVx

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / RRotU64.S

#------------------------------------------------------------------------------\r
#\r
# Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR>\r
# This program and the accompanying materials\r
# are licensed and made available under the terms and conditions of the BSD License\r
# which accompanies this distribution.  The full text of the license may be found at\r
# http://opensource.org/licenses/bsd-license.php.\r
#\r
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
#\r
# Module Name:\r
#\r
#   RRotU64.S\r
#\r
# Abstract:\r
#\r
#   64-bit right rotation for Ia32\r
#\r
#------------------------------------------------------------------------------\r
\r
ASM_GLOBAL ASM_PFX(InternalMathRRotU64)\r
\r
#------------------------------------------------------------------------------\r
# UINT64\r
# EFIAPI\r
# InternalMathRRotU64 (\r
#   IN      UINT64                    Operand,\r
#   IN      UINTN                     Count\r
#   );\r
#------------------------------------------------------------------------------\r
ASM_PFX(InternalMathRRotU64):\r
    push    %ebx\r
    movb    16(%esp), %cl\r
    movl    8(%esp), %eax\r
    movl    12(%esp), %edx\r
    shrdl   %cl, %eax, %ebx\r
    shrdl   %cl, %edx, %eax\r
    roll    %cl, %ebx\r
    shrdl   %cl, %ebx, %edx\r
    testb   $32, %cl                    # Count >= 32?\r
    jz      L0\r
    movl    %eax, %ecx                  # switch eax & edx if Count >= 32\r
    movl    %edx, %eax\r
    movl    %ecx, %edx\r
L0:    \r
    pop     %ebx\r
    ret\r