;; @file

; innotek Portable Runtime - ASMMultU64ByU32DivByU32().

;

;

; 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 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 "iprt/asmdefs.mac"

BEGINCODE

;;

; Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer

; using a 96 bit intermediate result.

;

; @returns (u64A * u32B) / u32C. (rax)

; @param u64A rcx The 64-bit value.

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

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

;

BEGINPROC_EXPORTED ASMMultU64ByU32DivByU32

mov r9d, edx ; r9 = B

mov rax, rcx ; rax = A

xor edx, edx ; rdx = 0

mul r9 ; rax:rdx = A*B

mov ecx, r8d ; rcx = C (overly careful)

div rcx ; rax = A*B/C (rdx=reminder)

ret

ENDPROC ASMMultU64ByU32DivByU32