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|
; $Id: support.asm $
;; @file
; Compiler support routines.
;
;
; Copyright (C) 2012 Oracle Corporation
;
; 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.
;
;*******************************************************************************
;* Exported Symbols *
;*******************************************************************************
public __U4D
public __U4M
ifndef VBOX_PC_BIOS
public __I4D
public __I4M
endif
public _fmemset_
public _fmemcpy_
.386p
_TEXT segment public 'CODE' use16
assume cs:_TEXT
;;
; 32-bit unsigned division.
;
; @param dx:ax Dividend.
; @param cx:bx Divisor.
; @returns dx:ax Quotient.
; cx:bx Reminder.
;
__U4D:
pushf
push eax
push edx
push ecx
rol eax, 16
mov ax, dx
ror eax, 16
xor edx, edx
shr ecx, 16
mov cx, bx
div ecx ; eax:edx / ecx -> eax=quotient, edx=reminder.
mov bx, dx
pop ecx
shr edx, 16
mov cx, dx
pop edx
ror eax, 16
mov dx, ax
add sp, 2
pop ax
rol eax, 16
popf
ret
ifndef VBOX_PC_BIOS
;;
; 32-bit signed division.
;
; @param dx:ax Dividend.
; @param cx:bx Divisor.
; @returns dx:ax Quotient.
; cx:bx Reminder.
;
__I4D:
pushf
push eax
push edx
push ecx
rol eax, 16
mov ax, dx
ror eax, 16
xor edx, edx
shr ecx, 16
mov cx, bx
idiv ecx ; eax:edx / ecx -> eax=quotient, edx=reminder.
mov bx, dx
pop ecx
shr edx, 16
mov cx, dx
pop edx
ror eax, 16
mov dx, ax
add sp, 2
pop ax
rol eax, 16
popf
ret
endif ; VBOX_PC_BIOS
;;
; 32-bit unsigned multiplication.
;
; @param dx:ax Factor 1.
; @param cx:bx Factor 2.
; @returns dx:ax Result.
;
__U4M:
pushf
push eax
push edx
push ecx
rol eax, 16
mov ax, dx
ror eax, 16
xor edx, edx
shr ecx, 16
mov cx, bx
mul ecx ; eax * ecx -> edx:eax
pop ecx
pop edx
ror eax, 16
mov dx, ax
add sp, 2
pop ax
rol eax, 16
popf
ret
ifndef VBOX_PC_BIOS
;;
; 32-bit unsigned multiplication.
; memset taking a far pointer.
;
; @param dx:ax Factor 1.
; @param cx:bx Factor 2.
; @returns dx:ax Result.
; cx, es may be modified; di is preserved
;
__I4M:
pushf
push eax
push edx
push ecx
push ebx
rol eax, 16
mov ax, dx
ror eax, 16
xor edx, edx
shr ecx, 16
mov cx, bx
imul ecx ; eax * ecx -> edx:eax
pop ebx
pop ecx
pop edx
ror eax, 16
mov dx, ax
add sp, 2
pop ax
rol eax, 16
popf
ret
endif ; VBOX_PC_BIOS
;;
; memset taking a far pointer.
;
; cx, es may be modified; di is preserved
;
; @returns dx:ax unchanged.
; @param dx:ax Pointer to the memory.
; @param bl The fill value.
; @param cx The number of bytes to fill.
;
_fmemset_:
push di
mov es, dx
mov di, ax
xchg al, bl
rep stosb
xchg al, bl
pop di
ret
;;
; memset taking far pointers.
;
; cx, es may be modified; si, di are preserved
;
; @returns dx:ax unchanged.
; @param dx:ax Pointer to the destination memory.
; @param cx:bx Pointer to the source memory.
; @param sp+2 The number of bytes to copy (dw).
;
_fmemcpy_:
push bp
mov bp, sp
push di
push ds
push si
mov es, dx
mov di, ax
mov ds, cx
mov si, bx
mov cx, [bp + 4]
rep movsb
pop si
pop ds
pop di
leave
ret
_TEXT ends
end
|
