; $Id$

;; @file

; IPRT - No-CRT memmove - AMD64 & X86.

;

;

; Copyright (C) 2006-2008 Sun Microsystems, Inc.

;

; This file is part of VirtualBox Open Source Edition (OSE), as

; available from http://www.virtualbox.org. This file is free software;

; you can redistribute it and/or modify it under the terms of the GNU

; General Public License (GPL) as published by the Free Software

; Foundation, in version 2 as it comes in the "COPYING" file of the

; VirtualBox OSE distribution. VirtualBox OSE is distributed in the

; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.

;

; The contents of this file may alternatively be used under the terms

; of the Common Development and Distribution License Version 1.0

; (CDDL) only, as it comes in the "COPYING.CDDL" file of the

; VirtualBox OSE distribution, in which case the provisions of the

; CDDL are applicable instead of those of the GPL.

;

; You may elect to license modified versions of this file under the

; terms and conditions of either the GPL or the CDDL or both.

;

; Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa

; Clara, CA 95054 USA or visit http://www.sun.com if you need

; additional information or have any questions.

;

%include "iprt/asmdefs.mac"

BEGINCODE

;;

; @param pvDst gcc: rdi msc: rcx x86:[esp+4]

; @param pvSrc gcc: rsi msc: rdx x86:[esp+8]

; @param cb gcc: rdx msc: r8 x86:[esp+0ch]

RT_NOCRT_BEGINPROC memmove

; Prolog.

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

mov r10, rdi ; save

mov r11, rsi ; save

mov rdi, rcx

mov rsi, rdx

mov rcx, r8

mov rdx, r8

%else

mov rcx, rdx

%endif

mov rax, rdi ; save the return value

%else

push edi

push esi

mov edi, [esp + 04h + 8]

mov esi, [esp + 08h + 8]

mov ecx, [esp + 0ch + 8]

mov edx, ecx

mov eax, edi ; save the return value

%endif

;

; Decide which direction to perform the copy in.

;

%if 1 ; keep it simpe for now.

cmp xDI, xSI

jnb .backward

;

; Slow/simple forward copy.

;

cld

rep movsb

jmp .epilog

%else ; disabled - it seems to work, but play safe for now.

;sub xAX, xSI

;jnb .backward

cmp xDI, xSI

jnb .backward

;

; Fast forward copy.

;

.fast_forward:

cld

%ifdef RT_ARCH_AMD64

shr rcx, 3

rep movsq

%else

shr ecx, 2

rep movsd

%endif

; The remaining bytes.

%ifdef RT_ARCH_AMD64

test dl, 4

jz .forward_dont_move_dword

movsd

%endif

.forward_dont_move_dword:

test dl, 2

jz .forward_dont_move_word

movsw

.forward_dont_move_word:

test dl, 1

jz .forward_dont_move_byte

movsb

.forward_dont_move_byte:

%endif ; disabled

;

; The epilog.

;

.epilog:

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

mov rdi, r10

mov rsi, r11

%endif

%else

pop esi

pop edi

%endif

ret

;

; Slow/simple backward copy.

;

ALIGNCODE(16)

.backward:

;; @todo check if they overlap.

lea xDI, [xDI + xCX - 1]

lea xSI, [xSI + xCX - 1]

std

rep movsb

cld

jmp .epilog

ENDPROC RT_NOCRT(memmove)