Mercurial > hg > graal-compiler
view graal/com.oracle.truffle.api/src/com/oracle/truffle/api/ExactMath.java @ 12432:90494fdf11c8
Merge.
author | Doug Simon <doug.simon@oracle.com> |
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date | Tue, 15 Oct 2013 23:06:27 +0200 |
parents | 494b818b527c |
children | 6a13c422fca4 |
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/* * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package com.oracle.truffle.api; /** * This class contains methods that will be part of java.lang.Math starting with JDK 8. Until JDK 8 * is release, we duplicate them here because they are generally useful for dynamic language * implementations. */ public class ExactMath { public static int addExact(int x, int y) { int r = x + y; // HD 2-12 Overflow iff both arguments have the opposite sign of the result if (((x ^ r) & (y ^ r)) < 0) { throw new ArithmeticException("integer overflow"); } return r; } public static long addExact(long x, long y) { long r = x + y; // HD 2-12 Overflow iff both arguments have the opposite sign of the result if (((x ^ r) & (y ^ r)) < 0) { throw new ArithmeticException("long overflow"); } return r; } public static int subtractExact(int x, int y) { int r = x - y; // HD 2-12 Overflow iff the arguments have different signs and // the sign of the result is different than the sign of x if (((x ^ y) & (x ^ r)) < 0) { throw new ArithmeticException("integer overflow"); } return r; } public static long subtractExact(long x, long y) { long r = x - y; // HD 2-12 Overflow iff the arguments have different signs and // the sign of the result is different than the sign of x if (((x ^ y) & (x ^ r)) < 0) { throw new ArithmeticException("long overflow"); } return r; } public static int multiplyExact(int x, int y) { long r = (long) x * (long) y; if ((int) r != r) { throw new ArithmeticException("long overflow"); } return (int) r; } public static long multiplyExact(long x, long y) { long r = x * y; long ax = Math.abs(x); long ay = Math.abs(y); if (((ax | ay) >>> 31 != 0)) { // Some bits greater than 2^31 that might cause overflow // Check the result using the divide operator // and check for the special case of Long.MIN_VALUE * -1 if (((y != 0) && (r / y != x)) || (x == Long.MIN_VALUE && y == -1)) { throw new ArithmeticException("long overflow"); } } return r; } }