[mirror_edk2.git] / MdePkg / Library / BaseMemoryLibRepStr / Ia32 / CopyMem.S

#------------------------------------------------------------------------------
#
# 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:
#
#------------------------------------------------------------------------------

.globl _InternalMemCopyMem

#------------------------------------------------------------------------------
#  VOID *
#  EFIAPI
#  InternalMemCopyMem (
#    IN VOID   *Destination,
#    IN VOID   *Source,
#    IN UINTN  Count
#    );
#------------------------------------------------------------------------------
_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
    jae     L_CopyBackward              # Copy backward if overlapped
L0:
    movl    %edx, %ecx
    andl    $3, %edx
    shrl    $2, %ecx
    rep
    movsl                               # Copy as many Dwords as possible
    jmp     L_CopyBytes
L_CopyBackward:
    movl    %eax, %esi                  # esi <- End of Source
    leal    -1(%edi, %edx), %edi        # edi <- End of Destination
    std
L_CopyBytes:
    movl    %edx, %ecx
    rep
    movsb                               # Copy bytes backward
    cld
    movl    12(%esp), %eax              # eax <- Destination as return value
    pop     %edi
    pop     %esi
    ret
Commit	Line	Data
b6bd81d4	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	# CopyMem.Asm
	15	#
	16	# Abstract:
	17	#
	18	# CopyMem function
	19	#
	20	# Notes:
	21	#
	22	#------------------------------------------------------------------------------
	23
b7089db1	24	.globl _InternalMemCopyMem
eb227e96	25
	26	#------------------------------------------------------------------------------
	27	# VOID *
	28	# EFIAPI
	29	# InternalMemCopyMem (
	30	# IN VOID *Destination,
	31	# IN VOID *Source,
	32	# IN UINTN Count
	33	# );
	34	#------------------------------------------------------------------------------
37867477	35	_InternalMemCopyMem:
b6bd81d4	36	push %esi
b6bd81d4	37	push %edi
eb227e96	38	movl 16(%esp), %esi # esi <- Source
	39	movl 12(%esp), %edi # edi <- Destination
	40	movl 20(%esp), %edx # edx <- Count
	41	leal -1(%esi, %edx), %eax # eax <- End of Source
	42	cmpl %edi, %esi
b6bd81d4	43	jae L0
eb227e96	44	cmpl %edi, %eax
b7089db1	45	jae L_CopyBackward # Copy backward if overlapped
eb227e96	46	L0:
	47	movl %edx, %ecx
	48	andl $3, %edx
	49	shrl $2, %ecx
b6bd81d4	50	rep
b6bd81d4	51	movsl # Copy as many Dwords as possible
b7089db1	52	jmp L_CopyBytes
b7089db1	53	L_CopyBackward:
eb227e96	54	movl %eax, %esi # esi <- End of Source
eb227e96	55	leal -1(%edi, %edx), %edi # edi <- End of Destination
b6bd81d4	56	std
b7089db1	57	L_CopyBytes:
eb227e96	58	movl %edx, %ecx
b6bd81d4	59	rep
	60	movsb # Copy bytes backward
	61	cld
eb227e96	62	movl 12(%esp), %eax # eax <- Destination as return value
f23c214d	63	pop %edi
f23c214d	64	pop %esi
b6bd81d4	65	ret