audk/MdePkg/Library/BaseMemoryLibMmx/X64/ZeroMem.nasm

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;------------------------------------------------------------------------------
;
; Copyright (c) 2006, 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:
;
; ZeroMem.nasm
;
; Abstract:
;
; ZeroMem function
;
; Notes:
;
;------------------------------------------------------------------------------
DEFAULT REL
SECTION .text
;------------------------------------------------------------------------------
; VOID *
; InternalMemZeroMem (
; IN VOID *Buffer,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemZeroMem)
ASM_PFX(InternalMemZeroMem):
push rdi
mov rdi, rcx
mov rcx, rdx
mov r8, rdi
and edx, 7
shr rcx, 3
jz @ZeroBytes
DB 0xf, 0xef, 0xc0 ; pxor mm0, mm0
.0:
DB 0xf, 0xe7, 7 ; movntq [rdi], mm0
add rdi, 8
loop .0
DB 0xf, 0xae, 0xf0 ; mfence
@ZeroBytes:
xor eax, eax
mov ecx, edx
rep stosb
mov rax, r8
pop rdi
ret