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 .xmm 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 lea eax, [esi + edx - 1] ; eax <- End of Source 42 cmp esi, edi 43 je @CopyMemDone 44 cmp edx, 0 45 je @CopyMemDone 46 cmp esi, edi 47 jae @F 48 cmp eax, edi ; Overlapped? 49 jae @CopyBackward ; Copy backward if overlapped 50 @@: 51 xor ecx, ecx 52 sub ecx, edi 53 and ecx, 15 ; ecx + edi aligns on 16-byte boundary 54 jz @F 55 cmp ecx, edx 56 cmova ecx, edx 57 sub edx, ecx ; edx <- remaining bytes to copy 58 rep movsb 59 @@: 60 mov ecx, edx 61 and edx, 15 62 shr ecx, 4 ; ecx <- # of DQwords to copy 63 jz @CopyBytes 64 add esp, -16 65 @@: 66 movdqu xmm0, [esi] ; esi may not be 16-bytes aligned 67 movdqa [edi], xmm0 ; edi should be 16-bytes aligned 68 add esi, 16 69 add edi, 16 70 loop @B 71 add esp, 16 ; stack cleanup 72 jmp @CopyBytes 73 @CopyBackward: 74 mov esi, eax ; esi <- Last byte in Source 75 lea edi, [edi + edx - 1] ; edi <- Last byte in Destination 76 std 77 @CopyBytes: 78 mov ecx, edx 79 rep movsb 80 cld 81 @CopyMemDone: 82 mov eax, [esp + 12] 83 ret 84 memcpy ENDP 85 86 END 87
