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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:
;
; EfiSetMem.asm
;
;Abstract:
;
; This is the code that supports IA32-optimized SetMem service
;
;--*/
;---------------------------------------------------------------------------
.686
.model flat,C
.mmx
.code
;---------------------------------------------------------------------------
;VOID
;EfiCommonLibSetMem (
; IN VOID *Buffer,
; IN UINTN Count,
; IN UINT8 Value
; )
;/*++
;
;Input: VOID *Buffer - Pointer to buffer to write
; UINTN Count - Number of bytes to write
; UINT8 Value - Value to write
;
;Output: None.
;
;Saves:
;
;Modifies:
;
;Description: This function is an optimized set-memory function.
;
;Notes: This function tries to set memory 8 bytes at a time. As a result,
; it first picks up any misaligned bytes, then words, before getting
; in the main loop that does the 8-byte clears.
;
;--*/
EfiCommonLibSetMem PROC
push ebp
mov ebp, esp
sub esp, 10h; Reserve space for local variable UINT64 QWordValue @[ebp - 10H] & UINT64 MmxSave @[ebp - 18H]
push ebx
push edi
mov edx, [ebp + 0Ch] ; Count
test edx, edx
je _SetMemDone
push ebx
mov eax, [ebp + 8] ; Buffer
mov bl, [ebp + 10h] ; Value
mov edi, eax
mov bh, bl
cmp edx, 256
jb _SetRemindingByte
and al, 07h
test al, al
je _SetBlock
mov eax, edi
shr eax, 3
inc eax
shl eax, 3
sub eax, edi
cmp eax, edx
jnb _SetRemindingByte
sub edx, eax
mov ecx, eax
mov al, bl
rep stosb
_SetBlock:
mov eax, edx
shr eax, 6
test eax, eax
je _SetRemindingByte
shl eax, 6
sub edx, eax
shr eax, 6
mov WORD PTR [ebp - 10H], bx ; QWordValue[0]
mov WORD PTR [ebp - 10H + 2], bx ; QWordValue[2]
mov WORD PTR [ebp - 10H + 4], bx ; QWordValue[4]
mov WORD PTR [ebp - 10H + 6], bx ; QWordValue[6]
movq [ebp - 8], mm0 ; Save mm0 to MmxSave
movq mm0, [ebp - 10H] ; Load QWordValue to mm0
_B:
movq QWORD PTR ds:[edi], mm0
movq QWORD PTR ds:[edi+8], mm0
movq QWORD PTR ds:[edi+16], mm0
movq QWORD PTR ds:[edi+24], mm0
movq QWORD PTR ds:[edi+32], mm0
movq QWORD PTR ds:[edi+40], mm0
movq QWORD PTR ds:[edi+48], mm0
movq QWORD PTR ds:[edi+56], mm0
add edi, 64
dec eax
jnz _B
; Restore mm0
movq mm0, [ebp - 8] ; Restore MmxSave to mm0
emms ; Exit MMX Instruction
_SetRemindingByte:
mov ecx, edx
mov eax, ebx
shl eax, 16
mov ax, bx
shr ecx, 2
rep stosd
mov ecx, edx
and ecx, 3
rep stosb
pop ebx
_SetMemDone:
pop edi
pop ebx
leave
ret
EfiCommonLibSetMem ENDP
END
|
