MdePkg/Library/BaseMemoryLibOptDxe/X64/CopyMem.S File Reference
Detailed Description
#
# ConvertAsm.py: Automatically generated from
CopyMem.asm
#
#------------------------------------------------------------------------------
#
# Copyright (c) 2006 - 2009, 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.S
#
# Abstract:
#
# CopyMem function
#
# Notes:
#
#------------------------------------------------------------------------------
#------------------------------------------------------------------------------
# VOID *
# EFIAPI
# InternalMemCopyMem (
# IN VOID *Destination,
# IN VOID *Source,
# IN UINTN Count
# )
#------------------------------------------------------------------------------
ASM_GLOBAL
ASM_PFX(InternalMemCopyMem)
ASM_PFX(InternalMemCopyMem):
pushq rsi
pushq rdi
movq rdx, rsi # rsi <- Source
movq rcx, rdi # rdi <- Destination
leaq -1(rsi,r8,), r9 # r9 <- Last byte of Source
cmpq rdi, rsi
movq rdi, rax # rax <- Destination as return value
jae L0 # Copy forward if Source > Destination
cmpq rdi, r9 # Overlapped?
jae L_CopyBackward # Copy backward if overlapped
L0:
xorq rcx, rcx
subq rdi, rcx # rcx <- -rdi
andq $15, rcx # rcx + rsi should be 16 bytes aligned
jz L1 # skip if rcx == 0
cmpq r8, rcx
cmova r8, rcx
subq rcx, r8
rep movsb
L1:
movq r8, rcx
andq $15, r8
shrq $4, rcx # rcx <- # of DQwords to copy
jz L_CopyBytes
movdqu xmm0, 0x18(rsp) # save xmm0 on stack
L2:
movdqu (rsi), xmm0 # rsi may not be 16-byte aligned
movntdq xmm0, (rdi) # rdi should be 16-byte aligned
addq $16, rsi
addq $16, rdi
loop L2
mfence
movdqa 0x18(rsp), xmm0 # restore xmm0
jmp L_CopyBytes # copy remaining bytes
L_CopyBackward:
movq r9, rsi # rsi <- Last byte of Source
leaq -1(rdi, r8,), rdi # rdi <- Last byte of Destination
std
L_CopyBytes:
movq r8, rcx
rep movsb
cld
popq rdi
popq rsi
ret