Update the copyright notice format

[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EfiCommonLib / Ia32 / EfiZeroMem.asm

;/*++\r
;\r
;Copyright (c) 2006, Intel Corporation                                                         \r
;All rights reserved. This program and the accompanying materials                          \r
;are licensed and made available under the terms and conditions of the BSD License         \r
;which accompanies this distribution.  The full text of the license may be found at        \r
;http://opensource.org/licenses/bsd-license.php                                            \r
;                                                                                          \r
;THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     \r
;WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             \r
;\r
;Module Name:\r
;\r
;  EfiZeroMem.c\r
;\r
;Abstract:\r
;\r
;  This is the code that supports IA32-optimized ZeroMem service\r
;\r
;--*/\r
;---------------------------------------------------------------------------\r
    .686\r
    .model  flat,C\r
    .mmx\r
    .code\r
\r
;---------------------------------------------------------------------------\r
;VOID\r
;EfiCommonLibZeroMem (\r
;  IN VOID   *Buffer,\r
;  IN UINTN  Count\r
;  )\r
;/*++\r
;\r
;Input:  VOID   *Buffer - Pointer to buffer to clear\r
;        UINTN  Count  - Number of bytes to clear\r
;\r
;Output: None.\r
;\r
;Saves:\r
;\r
;Modifies:\r
;\r
;Description:  This function is an optimized zero-memory function.\r
;\r
;Notes:  This function tries to zero memory 8 bytes at a time. As a result, \r
;        it first picks up any misaligned bytes, then words, before getting \r
;        in the main loop that does the 8-byte clears.\r
;\r
;--*/\r
EfiCommonLibZeroMem PROC\r
;  UINT64 MmxSave;\r
    push  ebp\r
    mov   ebp, esp\r
    push  ecx  ; Reserve space for local variable MmxSave\r
    push  ecx\r
    push  edi\r
    \r
    mov   ecx, [ebp + 0Ch] ; Count\r
    mov   edi, [ebp + 8]; Buffer\r
\r
    ; Pick up misaligned start bytes (get pointer 4-byte aligned)\r
_StartByteZero:\r
    mov   eax, edi    \r
    and   al, 3                       ; check lower 2 bits of address\r
    test  al, al\r
    je    _ZeroBlocks                 ; already aligned?\r
    cmp   ecx, 0\r
    je    _ZeroMemDone\r
\r
    ; Clear the byte memory location\r
    mov   BYTE PTR [edi], 0           \r
    inc    edi\r
\r
    ; Decrement our count\r
    dec    ecx\r
    jmp   _StartByteZero        ; back to top of loop\r
\r
_ZeroBlocks:\r
\r
    ; Compute how many 64-byte blocks we can clear \r
    mov   edx, ecx\r
    shr   ecx, 6                      ; convert to 64-byte count\r
    shl   ecx, 6                      ; convert back to bytes\r
    sub   edx, ecx                    ; subtract from the original count\r
    shr   ecx, 6                      ; and this is how many 64-byte blocks\r
\r
    ; If no 64-byte blocks, then skip \r
    cmp    ecx, 0\r
    je    _ZeroRemaining\r
\r
    ; Save mm0\r
    movq  [ebp - 8], mm0  ; Save mm0 to MmxSave\r
\r
    pxor  mm0, mm0          ; Clear mm0\r
\r
_B:\r
    movq  QWORD PTR ds:[edi], mm0\r
    movq  QWORD PTR ds:[edi+8], mm0\r
    movq  QWORD PTR ds:[edi+16], mm0\r
    movq  QWORD PTR ds:[edi+24], mm0\r
    movq  QWORD PTR ds:[edi+32], mm0\r
    movq  QWORD PTR ds:[edi+40], mm0\r
    movq  QWORD PTR ds:[edi+48], mm0\r
    movq  QWORD PTR ds:[edi+56], mm0\r
   \r
    add    edi, 64\r
    dec    ecx\r
    jnz    _B\r
  \r
; Restore mm0\r
    movq  mm0, [ebp - 8] ; Restore mm0 from MmxSave\r
    emms                                 ; Exit MMX Instruction\r
\r
_ZeroRemaining:\r
    ; Zero out as many DWORDS as possible\r
    mov   ecx, edx\r
    shr   ecx, 2\r
    xor   eax, eax\r
\r
    rep stosd\r
\r
    ; Zero out remaining as bytes\r
    mov   ecx, edx\r
    and   ecx, 03\r
\r
    rep   stosb\r
 \r
_ZeroMemDone:\r
\r
    pop    edi\r
    leave\r
    ret\r
EfiCommonLibZeroMem ENDP	\r
	END\r