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TITLE EfiSetMem.asm: Optimized setmemory routine
;------------------------------------------------------------------------------
;
; Copyright (c) 2004, 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:
;
; EfiCommonLibSetMem.asm
;
; Abstract:
;
; This is the code that supports IA32-optimized SetMem service
;
;------------------------------------------------------------------------------
; PROC:PRIVATE
.686P
.MMX
.XMM
.MODEL SMALL
.CODE
EfiCommonLibSetMem PROTO C Buffer:PTR DWORD, Count:DWORD, Value:BYTE
;------------------------------------------------------------------------------
; Procedure: EfiCommonLibSetMem
;
; 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 zero-memory function.
;
; Notes: This function tries to zero 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 C Buffer:PTR DWORD, Count:DWORD, Value:BYTE
LOCAL QWordValue:QWORD
LOCAL MmxSave:QWORD
mov edx, Count
test edx, edx
je _SetMemDone
push edi
push ebx
mov eax, Buffer
mov bl, Value
mov edi, eax
mov bh, bl
cmp edx, 256
jb _SetRemindingByte
and al, 0fh
test al, al
je _SetBlock
mov eax, edi
shr eax, 4
inc eax
shl eax, 4
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, 7
test eax, eax
je _SetRemindingByte
shl eax, 7
sub edx, eax
shr eax, 7
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
movq2dq xmm1, mm0
pshufd xmm1, xmm1, 0
@@:
movdqa OWORD PTR ds:[edi], xmm1
movdqa OWORD PTR ds:[edi+16], xmm1
movdqa OWORD PTR ds:[edi+32], xmm1
movdqa OWORD PTR ds:[edi+48], xmm1
movdqa OWORD PTR ds:[edi+64], xmm1
movdqa OWORD PTR ds:[edi+80], xmm1
movdqa OWORD PTR ds:[edi+96], xmm1
movdqa OWORD PTR ds:[edi+112], xmm1
add edi, 128
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
pop edi
_SetMemDone:
ret 0
EfiCommonLibSetMem ENDP
END
|
