; $Id$

;; @file

; IPRT - Assembly Functions, ASMMultU32ByU32DivByU32.

;

;

; Copyright (C) 2006-2010 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.

;

; 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.

;

%include "iprt/asmdefs.mac"

;;

; Multiple a 32-bit by a 32-bit integer and divide the result by a 32-bit integer

; using a 64 bit intermediate result.

;

; @returns (u32A * u32B) / u32C.

; @param u32A/ecx/edi The 32-bit value (A).

; @param u32B/edx/esi The 32-bit value to multiple by A.

; @param u32C/r8d/edx The 32-bit value to divide A*B by.

;

; @cproto DECLASM(uint32_t) ASMMultU32ByU32DivByU32(uint32_t u32A, uint32_t u32B, uint32_t u32C);

;

BEGINPROC_EXPORTED ASMMultU32ByU32DivByU32

%ifdef RT_ARCH_AMD64

%ifdef ASM_CALL64_MSC

mov eax, ecx ; rax = u32A

mov r9d, edx ; should check the specs wrt to the high bits one day...

mov r8d, r8d ; be paranoid for the time being.

%else

mov eax, edi ; rax = u32A

mov r9d, esi ; r9d = u32B

mov r8d, edx ; r8d = u32C

%endif

mul r9

div r8

%else ; X86

;

; This implementation is converted from the GCC inline

; version of the code. Nothing additional has been done

; performance wise.

;

%define u32A [esp + 04h]

%define u32B [esp + 08h]

%define u32C [esp + 0ch]

; Load parameters into registers.

mov eax, u32A

mul word u32B

div word u32C

%endif

ret

ENDPROC ASMMultU32ByU32DivByU32