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; memcpyRep8.asm 15; 16; Abstract: 17; 18; CopyMem function 19; 20; Notes: 21; 22;------------------------------------------------------------------------------ 23 24 .code 25 26;------------------------------------------------------------------------------ 27; VOID 28; memcpy ( 29; OUT VOID *Destination, 30; IN VOID *Source, 31; IN UINTN Count 32; ); 33;------------------------------------------------------------------------------ 34memcpy PROC USES rsi rdi 35 mov rax, rcx 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, 3 50 shr rcx, 2 51 rep movsd ; Copy as many Dwords as possible 52 jmp @CopyBytes 53@CopyBackward: 54 mov rsi, r9 ; rsi <- End of Source 55 lea rdi, [rdi + r8 - 1] ; esi <- End of Destination 56 std ; set direction flag 57@CopyBytes: 58 mov rcx, r8 59 rep movsb ; Copy bytes backward 60 cld 61@CopyMemDone: 62 ret 63memcpy ENDP 64 65 END 66