MdePkg/Library/BaseMemoryLibMmx/Ia32/CopyMem.S File Reference
Detailed Description
#------------------------------------------------------------------------------
#
# Copyright (c) 2006, Intel Corporation. All rights reserved.
# 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:
#
#
CopyMem.asm
#
# Abstract:
#
# CopyMem function
#
# Notes:
#
#------------------------------------------------------------------------------
ASM_GLOBAL
ASM_PFX(InternalMemCopyMem)
#------------------------------------------------------------------------------
# VOID *
# EFIAPI
# InternalMemCopyMem (
# IN VOID *Destination,
# IN VOID *Source,
# IN UINTN Count
# );
#------------------------------------------------------------------------------
ASM_PFX(InternalMemCopyMem):
push esi
push edi
movl 16(esp), esi # esi <- Source
movl 12(esp), edi # edi <- Destination
movl 20(esp), edx # edx <- Count
leal -1(esi,edx,), eax # eax <- End of Source
cmpl edi, esi
jae L0
cmpl edi, eax # Overlapped?
jae L_CopyBackward # Copy backward if overlapped
L0:
xorl ecx, ecx
subl esi, ecx
andl $7, ecx # ecx + esi aligns on 8-byte boundary
jz L1
cmpl edx, ecx
cmova edx, ecx
subl ecx, edx # edx <- remaining bytes to copy
rep
movsb
L1:
movl edx, ecx
andl $7, edx
shrl $3, ecx # ecx <- # of Qwords to copy
jz L_CopyBytes
pushl eax
pushl eax
movq mm0, (esp) # save mm0
L2:
movq (esi), mm0
movq mm0, (edi)
addl $8, esi
addl $8, edi
loop L2
movq (esp), mm0 # restore mm0
popl ecx # stack cleanup
popl ecx # stack cleanup
jmp L_CopyBytes
L_CopyBackward:
movl eax, esi # esi <- Last byte in Source
leal -1(edi,edx,), edi # edi <- Last byte in Destination
std
L_CopyBytes:
movl edx, ecx
rep
movsb
cld
movl 12(esp), eax
pop edi
pop esi
ret