1/* 2 * COPYRIGHT: See COPYING in the top level directory 3 * PROJECT: ReactOS kernel 4 * PURPOSE: Run-Time Library 5 * FILE: lib/sdk/crt/math/i386/allmul_asm.s 6 * PROGRAMER: Alex Ionescu (alex@relsoft.net) 7 * 8 * Copyright (C) 2002 Michael Ringgaard. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the project nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 24 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES// LOSS OF USE, DATA, OR PROFITS// OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37#include <asm.inc> 38 39PUBLIC __allmul 40 41/* FUNCTIONS ***************************************************************/ 42.code 43 44// 45// llmul - long multiply routine 46// 47// Purpose: 48// Does a long multiply (same for signed/unsigned) 49// Parameters are not changed. 50// 51// Entry: 52// Parameters are passed on the stack: 53// 1st pushed: multiplier (QWORD) 54// 2nd pushed: multiplicand (QWORD) 55// 56// Exit: 57// EDX:EAX - product of multiplier and multiplicand 58// NOTE: parameters are removed from the stack 59// 60// Uses: 61// ECX 62// 63 64__allmul: 65 66#define ALO [esp + 4] // stack address of a 67#define AHI [esp + 8] // stack address of a 68#define BLO [esp + 12] // stack address of b 69#define BHI [esp + 16] // stack address of b 70 71// 72// AHI, BHI : upper 32 bits of A and B 73// ALO, BLO : lower 32 bits of A and B 74// 75// ALO * BLO 76// ALO * BHI 77// + BLO * AHI 78// --------------------- 79// 80 81 mov eax,AHI 82 mov ecx,BHI 83 or ecx,eax //test for both hiwords zero. 84 mov ecx,BLO 85 jnz short hard //both are zero, just mult ALO and BLO 86 87 mov eax,ALO 88 mul ecx 89 90 ret 16 // callee restores the stack 91 92hard: 93 push ebx 94 95// must redefine A and B since esp has been altered 96 97#define A2LO [esp + 8] // stack address of a 98#define A2HI [esp + 12] // stack address of a 99#define B2LO [esp + 16] // stack address of b 100#define B2HI [esp + 20] // stack address of b 101 102 mul ecx //eax has AHI, ecx has BLO, so AHI * BLO 103 mov ebx,eax //save result 104 105 mov eax,A2LO 106 mul dword ptr B2HI //ALO * BHI 107 add ebx,eax //ebx = ((ALO * BHI) + (AHI * BLO)) 108 109 mov eax,A2LO //ecx = BLO 110 mul ecx //so edx:eax = ALO*BLO 111 add edx,ebx //now edx has all the LO*HI stuff 112 113 pop ebx 114 115 ret 16 // callee restores the stack 116 117END 118