Mercurial > hg > truffle
view graal/com.oracle.jvmci.code/src/com/oracle/jvmci/code/UnsignedMath.java @ 21787:2766fee1809a
Use the fact that a range checked array index is not negative to avoid sign-extension of the index register.
author | Roland Schatz <roland.schatz@oracle.com> |
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date | Mon, 08 Jun 2015 19:32:59 +0200 |
parents | 48c1ebd24120 |
children |
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/* * Copyright (c) 2011, 2011, 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. * * 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.jvmci.code; import java.math.*; //JaCoCo Exclude /** * Utilities for unsigned comparisons. All methods have correct, but slow, standard Java * implementations so that they can be used with compilers not supporting the intrinsics. */ public class UnsignedMath { private static final long MASK = 0xffffffffL; /** * Unsigned comparison aboveThan for two numbers. */ public static boolean aboveThan(int a, int b) { return (a & MASK) > (b & MASK); } /** * Unsigned comparison aboveOrEqual for two numbers. */ public static boolean aboveOrEqual(int a, int b) { return (a & MASK) >= (b & MASK); } /** * Unsigned comparison belowThan for two numbers. */ public static boolean belowThan(int a, int b) { return (a & MASK) < (b & MASK); } /** * Unsigned comparison belowOrEqual for two numbers. */ public static boolean belowOrEqual(int a, int b) { return (a & MASK) <= (b & MASK); } /** * Unsigned comparison aboveThan for two numbers. */ public static boolean aboveThan(long a, long b) { return (a > b) ^ ((a < 0) != (b < 0)); } /** * Unsigned comparison aboveOrEqual for two numbers. */ public static boolean aboveOrEqual(long a, long b) { return (a >= b) ^ ((a < 0) != (b < 0)); } /** * Unsigned comparison belowThan for two numbers. */ public static boolean belowThan(long a, long b) { return (a < b) ^ ((a < 0) != (b < 0)); } /** * Unsigned comparison belowOrEqual for two numbers. */ public static boolean belowOrEqual(long a, long b) { return (a <= b) ^ ((a < 0) != (b < 0)); } /** * Unsigned division for two numbers. */ public static int divide(int a, int b) { return (int) ((a & MASK) / (b & MASK)); } /** * Unsigned remainder for two numbers. */ public static int remainder(int a, int b) { return (int) ((a & MASK) % (b & MASK)); } /** * Unsigned division for two numbers. */ public static long divide(long a, long b) { return bi(a).divide(bi(b)).longValue(); } /** * Unsigned remainder for two numbers. */ public static long remainder(long a, long b) { return bi(a).remainder(bi(b)).longValue(); } private static BigInteger bi(long unsigned) { return unsigned >= 0 ? BigInteger.valueOf(unsigned) : BigInteger.valueOf(unsigned & 0x7fffffffffffffffL).setBit(63); } }