1 /*++ 2 3 Copyright (c) 2006, Intel Corporation. All rights reserved.<BR> 4 This program and the accompanying materials 5 are licensed and made available under the terms and conditions of the BSD License 6 which accompanies this distribution. The full text of the license may be found at 7 http://opensource.org/licenses/bsd-license.php 8 9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 11 12 Module Name: 13 14 DivU64x32.c 15 16 Abstract: 17 18 64-bit division function for IA-32 19 20 --*/ 21 22 #include "Tiano.h" 23 24 UINT64 25 DivU64x32 ( 26 IN UINT64 Dividend, 27 IN UINTN Divisor, 28 OUT UINTN *Remainder OPTIONAL 29 ) 30 /*++ 31 32 Routine Description: 33 34 This routine allows a 64 bit value to be divided with a 32 bit value returns 35 64bit result and the Remainder. 36 37 Arguments: 38 39 Dividend - dividend 40 Divisor - divisor 41 Remainder - buffer for remainder 42 43 Returns: 44 45 Dividend / Divisor 46 Remainder = Dividend mod Divisor 47 48 N.B. only works for 31bit divisors!! 49 50 --*/ 51 { 52 __asm { 53 xor edx, edx ; Clear EDX 54 55 mov eax, dword ptr Dividend[4] ; Put high 32 bits of 64-bit dividend in EAX 56 mov ecx, Divisor ; Put 32 bits divisor in ECX 57 div ecx ; Dividend Divisor Quoitent...Remainder 58 ; 0:EAX / ECX = EAX EDX 59 60 push eax ; Push quoitent in stack 61 62 mov eax, dword ptr Dividend[0] ; Put low 32 bits of 64-bit dividend in EAX 63 div ecx ; Leave the REMAINDER in EDX as High 32-bit of new dividend 64 ; Dividend Divisor Quoitent...Remainder 65 ; EDX:EAX / ECX = EAX EDX 66 67 mov ecx, Remainder ; Put &REMAINDER to ecx 68 69 jecxz Label1 ; If ecx == 0, no remainder exist, return with quoitent in EDX directly 70 mov dword ptr [ecx], edx ; Put EDX through REMAINDER pointer in ECX 71 72 Label1: 73 pop edx ; Pop High 32-bit QUOITENT to EDX 74 } 75 } 76
