projects / mirror_edk2.git / blame
| Commit | Line | Data |
|---|---|---|
| 3eb9473e | 1 | ;------------------------------------------------------------------------------\r |
| 2 | ;\r | |
| 4ea9375a HT |
3 | ; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR>\r |
| 4 | ; This program and the accompanying materials\r | |
| 3eb9473e | 5 | ; are licensed and made available under the terms and conditions of the BSD License\r |
| 6 | ; which accompanies this distribution. The full text of the license may be found at\r | |
| 7 | ; http://opensource.org/licenses/bsd-license.php\r | |
| 8 | ;\r | |
| 9 | ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
| 10 | ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
| 11 | ;\r | |
| 12 | ; Module Name:\r | |
| 13 | ;\r | |
| 14 | ; CopyMem.asm\r | |
| 15 | ;\r | |
| 16 | ; Abstract:\r | |
| 17 | ;\r | |
| 18 | ; memcpy function\r | |
| 19 | ;\r | |
| 20 | ; Notes:\r | |
| 21 | ;\r | |
| 22 | ;------------------------------------------------------------------------------\r | |
| 23 | \r | |
| 24 | .code\r | |
| 25 | \r | |
| 26 | ;------------------------------------------------------------------------------\r | |
| 27 | ; VOID *\r | |
| 28 | ; memcpy (\r | |
| 29 | ; OUT VOID *DestinationBuffer,\r | |
| 30 | ; IN CONST VOID *SourceBuffer,\r | |
| 31 | ; IN UINTN Length\r | |
| 32 | ; );\r | |
| 33 | ;------------------------------------------------------------------------------\r | |
| 34 | memcpy PROC USES rsi rdi\r | |
| 35 | mov rax, rcx ; rax <- Destination as return value\r | |
| 36 | cmp rdx, rcx ; if Source == Destination, do nothing\r | |
| 37 | je @CopyMemDone\r | |
| 38 | cmp r8, 0 ; if Count == 0, do nothing\r | |
| 39 | je @CopyMemDone\r | |
| 40 | mov rsi, rdx ; rsi <- Source\r | |
| 41 | mov rdi, rcx ; rdi <- Destination\r | |
| 42 | lea r9, [rsi + r8 - 1] ; r9 <- Last byte of Source\r | |
| 43 | cmp rsi, rdi\r | |
| 44 | jae @F ; Copy forward if Source > Destination\r | |
| 45 | cmp r9, rdi ; Overlapped?\r | |
| 46 | jae @CopyBackward ; Copy backward if overlapped\r | |
| 47 | @@:\r | |
| 48 | xor rcx, rcx\r | |
| 49 | sub rcx, rdi ; rcx <- -rdi\r | |
| 50 | and rcx, 15 ; rcx + rsi should be 16 bytes aligned\r | |
| 51 | jz @F ; skip if rcx == 0\r | |
| 52 | cmp rcx, r8\r | |
| 53 | cmova rcx, r8\r | |
| 54 | sub r8, rcx\r | |
| 55 | rep movsb\r | |
| 56 | @@:\r | |
| 57 | mov rcx, r8\r | |
| 58 | and r8, 15\r | |
| 59 | shr rcx, 4 ; rcx <- # of DQwords to copy\r | |
| 60 | jz @CopyBytes\r | |
| 61 | @@:\r | |
| 62 | movdqu xmm0, [rsi] ; rsi may not be 16-byte aligned\r | |
| 63 | movdqa [rdi], xmm0 ; rdi should be 16-byte aligned\r | |
| 64 | add rsi, 16\r | |
| 65 | add rdi, 16\r | |
| 66 | loop @B\r | |
| 67 | jmp @CopyBytes ; copy remaining bytes\r | |
| 68 | @CopyBackward:\r | |
| 69 | mov rsi, r9 ; rsi <- Last byte of Source\r | |
| 70 | lea rdi, [rdi + r8 - 1] ; rdi <- Last byte of Destination\r | |
| 71 | std\r | |
| 72 | @CopyBytes:\r | |
| 73 | mov rcx, r8\r | |
| 74 | rep movsb\r | |
| 75 | cld\r | |
| 76 | @CopyMemDone: \r | |
| 77 | ret\r | |
| 78 | memcpy ENDP\r | |
| 79 | \r | |
| 80 | END\r |