audk/MdePkg/Library/BaseMemoryLibOptDxe/x64/ZeroMem.asm

49 lines
1.4 KiB
NASM

;------------------------------------------------------------------------------
;
; 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:
;
; ZeroMem.Asm
;
; Abstract:
;
; ZeroMem function
;
; Notes:
;
;------------------------------------------------------------------------------
.code
;------------------------------------------------------------------------------
; VOID *
; InternalMemZeroMem (
; IN VOID *Buffer,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
InternalMemZeroMem PROC USES rdi
push rcx ; push Buffer
xor rax, rax ; rax = 0
mov rdi, rcx ; rdi = Buffer
mov rcx, rdx ; rcx = Count
shr rcx, 3 ; rcx = rcx / 8
and rdx, 7 ; rdx = rdx & 7
cld
rep stosq
mov rcx, rdx ; rcx = rdx
rep stosb
pop rax ; rax = Buffer
ret
InternalMemZeroMem ENDP
END