13fb3ca8c7ca439d408449a395897395c0faae8d1Ben Murdoch// Copyright 2011 the V8 project authors. All rights reserved. 2402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// Redistribution and use in source and binary forms, with or without 3402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// modification, are permitted provided that the following conditions are 4402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// met: 5402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// 6402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// * Redistributions of source code must retain the above copyright 7402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// notice, this list of conditions and the following disclaimer. 8402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// * Redistributions in binary form must reproduce the above 9402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// copyright notice, this list of conditions and the following 10402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// disclaimer in the documentation and/or other materials provided 11402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// with the distribution. 12402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// * Neither the name of Google Inc. nor the names of its 13402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// contributors may be used to endorse or promote products derived 14402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// from this software without specific prior written permission. 15402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// 16402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu 283fb3ca8c7ca439d408449a395897395c0faae8d1Ben Murdoch#include "../include/v8stdint.h" 293fb3ca8c7ca439d408449a395897395c0faae8d1Ben Murdoch#include "globals.h" 303fb3ca8c7ca439d408449a395897395c0faae8d1Ben Murdoch#include "checks.h" 316ded16be15dd865a9b21ea304d5273c8be299c87Steve Block#include "diy-fp.h" 32402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu 33402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescunamespace v8 { 34402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescunamespace internal { 35402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu 366ded16be15dd865a9b21ea304d5273c8be299c87Steve Blockvoid DiyFp::Multiply(const DiyFp& other) { 376ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // Simply "emulates" a 128 bit multiplication. 386ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // However: the resulting number only contains 64 bits. The least 396ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // significant 64 bits are only used for rounding the most significant 64 406ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // bits. 416ded16be15dd865a9b21ea304d5273c8be299c87Steve Block const uint64_t kM32 = 0xFFFFFFFFu; 426ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t a = f_ >> 32; 436ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t b = f_ & kM32; 446ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t c = other.f_ >> 32; 456ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t d = other.f_ & kM32; 466ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t ac = a * c; 476ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t bc = b * c; 486ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t ad = a * d; 496ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t bd = b * d; 506ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t tmp = (bd >> 32) + (ad & kM32) + (bc & kM32); 516ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // By adding 1U << 31 to tmp we round the final result. 526ded16be15dd865a9b21ea304d5273c8be299c87Steve Block // Halfway cases will be round up. 536ded16be15dd865a9b21ea304d5273c8be299c87Steve Block tmp += 1U << 31; 546ded16be15dd865a9b21ea304d5273c8be299c87Steve Block uint64_t result_f = ac + (ad >> 32) + (bc >> 32) + (tmp >> 32); 556ded16be15dd865a9b21ea304d5273c8be299c87Steve Block e_ += other.e_ + 64; 566ded16be15dd865a9b21ea304d5273c8be299c87Steve Block f_ = result_f; 576ded16be15dd865a9b21ea304d5273c8be299c87Steve Block} 58402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu 59402d937239b0e2fd11bf2f4fe972ad78aa9fd481Andrei Popescu} } // namespace v8::internal 60