| 1 | ;; @file
|
|---|
| 2 | ; innotek Portable Runtime - ASMMultU64ByU32DivByU32().
|
|---|
| 3 | ;
|
|---|
| 4 |
|
|---|
| 5 | ;
|
|---|
| 6 | ; Copyright (C) 2006-2007 innotek GmbH
|
|---|
| 7 | ;
|
|---|
| 8 | ; This file is part of VirtualBox Open Source Edition (OSE), as
|
|---|
| 9 | ; available from http://www.virtualbox.org. This file is free software;
|
|---|
| 10 | ; you can redistribute it and/or modify it under the terms of the GNU
|
|---|
| 11 | ; General Public License as published by the Free Software Foundation,
|
|---|
| 12 | ; in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
|
|---|
| 13 | ; distribution. VirtualBox OSE is distributed in the hope that it will
|
|---|
| 14 | ; be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 15 |
|
|---|
| 16 | ;*******************************************************************************
|
|---|
| 17 | ;* Header Files *
|
|---|
| 18 | ;*******************************************************************************
|
|---|
| 19 | %include "iprt/asmdefs.mac"
|
|---|
| 20 |
|
|---|
| 21 | BEGINCODE
|
|---|
| 22 |
|
|---|
| 23 | ;;
|
|---|
| 24 | ; Multiple a 64-bit by a 32-bit integer and divide the result by a 32-bit integer
|
|---|
| 25 | ; using a 96 bit intermediate result.
|
|---|
| 26 | ;
|
|---|
| 27 | ; @returns (u64A * u32B) / u32C. (rax)
|
|---|
| 28 | ; @param u64A rcx The 64-bit value.
|
|---|
| 29 | ; @param u32B edx The 32-bit value to multiple by A.
|
|---|
| 30 | ; @param u32C r8d The 32-bit value to divide A*B by.
|
|---|
| 31 | ;
|
|---|
| 32 | BEGINPROC_EXPORTED ASMMultU64ByU32DivByU32
|
|---|
| 33 | mov r9d, edx ; r9 = B
|
|---|
| 34 | mov rax, rcx ; rax = A
|
|---|
| 35 | xor edx, edx ; rdx = 0
|
|---|
| 36 | mul r9 ; rax:rdx = A*B
|
|---|
| 37 | mov ecx, r8d ; rcx = C (overly careful)
|
|---|
| 38 | div rcx ; rax = A*B/C (rdx=reminder)
|
|---|
| 39 | ret
|
|---|
| 40 | ENDPROC ASMMultU64ByU32DivByU32
|
|---|
| 41 |
|
|---|
