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 .code 25 26 ;------------------------------------------------------------------------------ 27 ; VOID * 28 ; memcpy ( 29 ; OUT VOID *DestinationBuffer, 30 ; IN CONST VOID *SourceBuffer, 31 ; IN UINTN Length 32 ; ); 33 ;------------------------------------------------------------------------------ 34 memcpy PROC USES rsi rdi 35 mov rax, rcx ; rax <- Destination as return value 36 cmp rdx, rcx ; if Source == Destination, do nothing 37 je @CopyMemDone 38 cmp r8, 0 ; if Count == 0, do nothing 39 je @CopyMemDone 40 mov rsi, rdx ; rsi <- Source 41 mov rdi, rcx ; rdi <- Destination 42 lea r9, [rsi + r8 - 1] ; r9 <- End of Source 43 cmp rsi, rdi 44 jae @F 45 cmp r9, rdi 46 jae @CopyBackward ; Copy backward if overlapped 47 @@: 48 mov rcx, r8 49 and r8, 7 50 shr rcx, 3 ; rcx <- # of Qwords to copy 51 jz @CopyBytes 52 DB 49h, 0fh, 7eh, 0c2h ; movd r10, mm0 (Save mm0 in r10) 53 @@: 54 DB 0fh, 6fh, 06h ; movd mm0, [rsi] 55 DB 48h, 0fh, 7eh, 07h ; movd [rdi], mm0 56 add rsi, 8 57 add rdi, 8 58 loop @B 59 DB 49h, 0fh, 6eh, 0c2h ; movd mm0, r10 (Restore mm0) 60 jmp @CopyBytes 61 @CopyBackward: 62 mov rsi, r9 ; rsi <- End of Source 63 lea rdi, [rdi + r8 - 1] ; rdi <- End of Destination 64 std ; set direction flag 65 @CopyBytes: 66 mov rcx, r8 67 rep movsb ; Copy bytes backward 68 cld 69 @CopyMemDone: 70 ret 71 memcpy ENDP 72 73 END 74
