1 ;------------------------------------------------------------------------------ 2 ; 3 ; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR> 4 ; This program and the accompanying materials 5 ; are licensed and made available under the terms and conditions of the BSD License 6 ; which accompanies this distribution. The full text of the license may be found at 7 ; http://opensource.org/licenses/bsd-license.php 8 ; 9 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 ; 12 ; Module Name: 13 ; 14 ; CopyMem.asm 15 ; 16 ; Abstract: 17 ; 18 ; memcpy function 19 ; 20 ; Notes: 21 ; 22 ;------------------------------------------------------------------------------ 23 24 .686 25 .model flat,C 26 .mmx 27 .code 28 29 ;------------------------------------------------------------------------------ 30 ; VOID * 31 ; memcpy ( 32 ; IN VOID *Destination, 33 ; IN VOID *Source, 34 ; IN UINTN Count 35 ; ); 36 ;------------------------------------------------------------------------------ 37 memcpy PROC USES esi edi 38 mov esi, [esp + 16] ; esi <- Source 39 mov edi, [esp + 12] ; edi <- Destination 40 mov edx, [esp + 20] ; edx <- Count 41 cmp esi, edi 42 je @CopyDone 43 cmp edx, 0 44 je @CopyDone 45 lea eax, [esi + edx - 1] ; eax <- End of Source 46 cmp esi, edi 47 jae @F 48 cmp eax, edi 49 jae @CopyBackward ; Copy backward if overlapped 50 @@: 51 mov ecx, edx 52 and edx, 3 53 shr ecx, 2 54 rep movsd ; Copy as many Dwords as possible 55 jmp @CopyBytes 56 @CopyBackward: 57 mov esi, eax ; esi <- End of Source 58 lea edi, [edi + edx - 1] ; edi <- End of Destination 59 std 60 @CopyBytes: 61 mov ecx, edx 62 rep movsb ; Copy bytes backward 63 cld 64 @CopyDone: 65 mov eax, [esp + 12] 66 ret 67 68 memcpy ENDP 69 70 END 71
