audk/MdePkg/Library/BaseMemoryLibOptDxe/Ia32/CompareMem.nasm

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;------------------------------------------------------------------------------
;
; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php.
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; CompareMem.Asm
;
; Abstract:
;
; CompareMem function
;
; Notes:
;
; The following BaseMemoryLib instances contain the same copy of this file:
;
; BaseMemoryLibRepStr
; BaseMemoryLibMmx
; BaseMemoryLibSse2
; BaseMemoryLibOptDxe
; BaseMemoryLibOptPei
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; INTN
; EFIAPI
; InternalMemCompareMem (
; IN CONST VOID *DestinationBuffer,
; IN CONST VOID *SourceBuffer,
; IN UINTN Length
; );
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemCompareMem)
ASM_PFX(InternalMemCompareMem):
push esi
push edi
mov esi, [esp + 12]
mov edi, [esp + 16]
mov ecx, [esp + 20]
repe cmpsb
movzx eax, byte [esi - 1]
movzx edx, byte [edi - 1]
sub eax, edx
pop edi
pop esi
ret