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;------------------------------------------------------------------------------
;
; Copyright (c) 2007, 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:
;
; SetMem.asm
;
; Abstract:
;
; memset function
;
; Notes:
;
;------------------------------------------------------------------------------
.code
;------------------------------------------------------------------------------
; VOID *
; memset (
; OUT VOID *Buffer, --> rcx
; IN UINT8 Value, --> rdx
; IN UINTN Length --> r8
; );
;------------------------------------------------------------------------------
memset PROC USES rdi
mov rax, rcx
cmp r8, 0 ; if Size == 0, do nothing
je @SetDone
mov rax, rdx ; rdx <-> r8
mov rdx, r8 ; rdx <- Length
mov r8, rax ; r8 <- Value
mov rdi, rcx ; rdi <- Buffer
mov al, r8b ; al <- Value
mov r9, rdi ; r9 <- Buffer as return value
xor rcx, rcx
sub rcx, rdi
and rcx, 15 ; rcx + rdi aligns on 16-byte boundary
jz @F
cmp rcx, rdx
cmova rcx, rdx
sub rdx, rcx
rep stosb
@@:
mov rcx, rdx
and rdx, 15
shr rcx, 4
jz @SetBytes
mov ah, al ; ax <- Value repeats twice
movd xmm0, eax ; xmm0[0..16] <- Value repeats twice
pshuflw xmm0, xmm0, 0 ; xmm0[0..63] <- Value repeats 8 times
movlhps xmm0, xmm0 ; xmm0 <- Value repeats 16 times
@@:
movdqa [rdi], xmm0 ; rdi should be 16-byte aligned
add rdi, 16
loop @B
@SetBytes:
mov ecx, edx ; high 32 bits of rcx are always zero
rep stosb
mov rax, r9 ; rax <- Return value
@SetDone:
ret
memset ENDP
END
|
