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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.c
Abstract:
This is the code that supports IA32-optimized SetMem service
--*/
#include "Tiano.h"
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.
--*/
{
UINT64 QWordValue;
UINT64 MmxSave;
__asm {
mov edx, Count
test edx, edx
je _SetMemDone
push ebx
mov eax, Buffer
mov bl, 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 QWordValue[0], bx
mov WORD PTR QWordValue[2], bx
mov WORD PTR QWordValue[4], bx
mov WORD PTR QWordValue[6], bx
movq MmxSave, mm0
movq mm0, QWordValue
_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, MmxSave
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:
}
}
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