; $Id: EMAllA.asm 20278 2007-04-09 11:56:29Z sandervl $

;; @file

; EM Assembly Routines.

;

;

; Copyright (C) 2006-2007 innotek GmbH

;

; 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.

;

;*******************************************************************************

;* Header Files *

;*******************************************************************************

%include "VBox/asmdefs.mac"

%include "VBox/err.mac"

%include "VBox/x86.mac"

BEGINCODE

;;

; Emulate lock CMPXCHG instruction, CDECL calling conv.

; EMGCDECL(uint32_t) EMGCEmulateLockCmpXchg(RTGCPTR pu32Param1, uint32_t *pu32Param2, uint32_t u32Param3, size_t cbSize, uint32_t *pEflags);

;

; @returns eax=0 if data written, other code - invalid access, #PF was generated.

; @param [esp + 04h] Param 1 - First parameter - pointer to first parameter

; @param [esp + 08h] Param 2 - Second parameter - pointer to second parameter (eax)

; @param [esp + 0ch] Param 3 - Third parameter - third parameter

; @param [esp + 10h] Param 4 - Size of parameters, only 1/2/4 is valid.

; @param [esp + 14h] Param 4 - Pointer to eflags (out)

; @uses eax, ecx, edx

;

align 16

BEGINPROC EMGCEmulateLockCmpXchg

push ebx

mov ecx, [esp + 04h + 4] ; ecx = first parameter

mov ebx, [esp + 08h + 4] ; ebx = 2nd parameter (eax)

mov edx, [esp + 0ch + 4] ; edx = third parameter

mov eax, [esp + 10h + 4] ; eax = size of parameters

cmp al, 4

je short .do_dword ; 4 bytes variant

cmp al, 2

je short .do_word ; 2 byte variant

cmp al, 1

je short .do_byte ; 1 bytes variant

int3

.do_dword:

; load 2nd parameter's value

mov eax, dword [ebx]

lock cmpxchg dword [ecx], edx ; do 4 bytes CMPXCHG

mov dword [ebx], eax

jmp short .done

.do_word:

; load 2nd parameter's value

mov eax, dword [ebx]

lock cmpxchg word [ecx], dx ; do 2 bytes CMPXCHG

mov word [ebx], ax

jmp short .done

.do_byte:

; load 2nd parameter's value

mov eax, dword [ebx]

lock cmpxchg byte [ecx], dl ; do 1 bytes CMPXCHG

mov byte [ebx], al

.done:

; collect flags and return.

pushf

pop eax

mov edx, [esp + 14h + 4] ; eflags pointer

mov dword [edx], eax

pop ebx

mov eax, VINF_SUCCESS

retn

; Read error - we will be here after our page fault handler.

GLOBALNAME EMGCEmulateLockCmpXchg_Error

pop ebx

mov eax, VERR_ACCESS_DENIED

ret

ENDPROC EMGCEmulateLockCmpXchg

;;

; Emulate CMPXCHG instruction, CDECL calling conv.

; EMGCDECL(uint32_t) EMGCEmulateCmpXchg(RTGCPTR pu32Param1, uint32_t *pu32Param2, uint32_t u32Param3, size_t cbSize, uint32_t *pEflags);

;

; @returns eax=0 if data written, other code - invalid access, #PF was generated.

; @param [esp + 04h] Param 1 - First parameter - pointer to first parameter

; @param [esp + 08h] Param 2 - Second parameter - pointer to second parameter (eax)

; @param [esp + 0ch] Param 3 - Third parameter - third parameter

; @param [esp + 10h] Param 4 - Size of parameters, only 1/2/4 is valid.

; @param [esp + 14h] Param 4 - Pointer to eflags (out)

; @uses eax, ecx, edx

;

align 16

BEGINPROC EMGCEmulateCmpXchg

push ebx

mov ecx, [esp + 04h + 4] ; ecx = first parameter

mov ebx, [esp + 08h + 4] ; ebx = 2nd parameter (eax)

mov edx, [esp + 0ch + 4] ; edx = third parameter

mov eax, [esp + 10h + 4] ; eax = size of parameters

cmp al, 4

je short .do_dword ; 4 bytes variant

cmp al, 2

je short .do_word ; 2 byte variant

cmp al, 1

je short .do_byte ; 1 bytes variant

int3

.do_dword:

; load 2nd parameter's value

mov eax, dword [ebx]

cmpxchg dword [ecx], edx ; do 4 bytes CMPXCHG

mov dword [ebx], eax

jmp short .done

.do_word:

; load 2nd parameter's value

mov eax, dword [ebx]

cmpxchg word [ecx], dx ; do 2 bytes CMPXCHG

mov word [ebx], ax

jmp short .done

.do_byte:

; load 2nd parameter's value

mov eax, dword [ebx]

cmpxchg byte [ecx], dl ; do 1 bytes CMPXCHG

mov byte [ebx], al

.done:

; collect flags and return.

pushf

pop eax

mov edx, [esp + 14h + 4] ; eflags pointer

mov dword [edx], eax

pop ebx

mov eax, VINF_SUCCESS

retn

; Read error - we will be here after our page fault handler.

GLOBALNAME EMGCEmulateCmpXchg_Error

pop ebx

mov eax, VERR_ACCESS_DENIED

ret

ENDPROC EMGCEmulateCmpXchg