[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EfiCommonLib / X64 / EfiCopyMemRep4.asm

;------------------------------------------------------------------------------\r
;\r
; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR>\r
; This program and the accompanying materials\r
; are licensed and made available under the terms and conditions of the BSD License\r
; which accompanies this distribution.  The full text of the license may be found at\r
; http://opensource.org/licenses/bsd-license.php\r
;\r
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
;\r
; Module Name:\r
;\r
;   EfiCopyMemRep4.asm\r
;\r
; Abstract:\r
;\r
;   CopyMem function\r
;\r
; Notes:\r
;\r
;------------------------------------------------------------------------------\r
\r
    .code\r
\r
;------------------------------------------------------------------------------\r
; VOID\r
; EfiCommonLibCopyMem (\r
;   OUT     VOID                      *Destination,\r
;   IN      VOID                      *Source,\r
;   IN      UINTN                     Count\r
;   );\r
;------------------------------------------------------------------------------\r
EfiCommonLibCopyMem  PROC    USES    rsi rdi\r
    cmp     rdx, rcx                    ; if Source == Destination, do nothing\r
    je      @CopyMemDone\r
    cmp     r8, 0                       ; if Count == 0, do nothing\r
    je      @CopyMemDone\r
    mov     rsi, rdx                    ; rsi <- Source\r
    mov     rdi, rcx                    ; rdi <- Destination\r
    lea     r9, [rsi + r8 - 1]          ; r9 <- End of Source\r
    cmp     rsi, rdi\r
    jae     @F\r
    cmp     r9, rdi\r
    jae     @CopyBackward               ; Copy backward if overlapped\r
@@:\r
    mov     rcx, r8\r
    and     r8, 3\r
    shr     rcx, 2\r
    rep     movsd                       ; Copy as many Dwords as possible\r
    jmp     @CopyBytes\r
@CopyBackward:\r
    mov     rsi, r9                     ; rsi <- End of Source\r
    lea     rdi, [rdi + r8 - 1]         ; esi <- End of Destination\r
    std                                 ; set direction flag\r
@CopyBytes:\r
    mov     rcx, r8\r
    rep     movsb                       ; Copy bytes backward\r
    cld\r
@CopyMemDone:\r
    ret\r
EfiCommonLibCopyMem  ENDP\r
\r
    END\r
\r
Commit	Line	Data
	1	;------------------------------------------------------------------------------\r
	2	;\r
	3	; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR>\r
	4	; This program and the accompanying materials\r
	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	; EfiCopyMemRep4.asm\r
	15	;\r
	16	; Abstract:\r
	17	;\r
	18	; CopyMem function\r
	19	;\r
	20	; Notes:\r
	21	;\r
	22	;------------------------------------------------------------------------------\r
	23	\r
	24	.code\r
	25	\r
	26	;------------------------------------------------------------------------------\r
	27	; VOID\r
	28	; EfiCommonLibCopyMem (\r
	29	; OUT VOID *Destination,\r
	30	; IN VOID *Source,\r
	31	; IN UINTN Count\r
	32	; );\r
	33	;------------------------------------------------------------------------------\r
	34	EfiCommonLibCopyMem PROC USES rsi rdi\r
	35	cmp rdx, rcx ; if Source == Destination, do nothing\r
	36	je @CopyMemDone\r
	37	cmp r8, 0 ; if Count == 0, do nothing\r
	38	je @CopyMemDone\r
	39	mov rsi, rdx ; rsi <- Source\r
	40	mov rdi, rcx ; rdi <- Destination\r
	41	lea r9, [rsi + r8 - 1] ; r9 <- End of Source\r
	42	cmp rsi, rdi\r
	43	jae @F\r
	44	cmp r9, rdi\r
	45	jae @CopyBackward ; Copy backward if overlapped\r
	46	@@:\r
	47	mov rcx, r8\r
	48	and r8, 3\r
	49	shr rcx, 2\r
	50	rep movsd ; Copy as many Dwords as possible\r
	51	jmp @CopyBytes\r
	52	@CopyBackward:\r
	53	mov rsi, r9 ; rsi <- End of Source\r
	54	lea rdi, [rdi + r8 - 1] ; esi <- End of Destination\r
	55	std ; set direction flag\r
	56	@CopyBytes:\r
	57	mov rcx, r8\r
	58	rep movsb ; Copy bytes backward\r
	59	cld\r
	60	@CopyMemDone:\r
	61	ret\r
	62	EfiCommonLibCopyMem ENDP\r
	63	\r
	64	END\r
	65	\r