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Truffle is a multi-language framework for executing dynamic languages
that achieves high performance when combined with Graal.
/*
* 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.
*
* @since 0.8 or earlier
*/
public class ExactMath {
/**
* @deprecated accidentally public - don't use
* @since 0.8 or earlier
*/
@Deprecated
public ExactMath() {
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
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;
}
/** @since 0.8 or earlier */
public static int multiplyHigh(int x, int y) {
long r = (long) x * (long) y;
return (int) (r >> 32);
}
/** @since 0.8 or earlier */
public static int multiplyHighUnsigned(int x, int y) {
long xl = x & 0xFFFFFFFFL;
long yl = y & 0xFFFFFFFFL;
long r = xl * yl;
return (int) (r >> 32);
}
/** @since 0.8 or earlier */
public static long multiplyHigh(long x, long y) {
// Checkstyle: stop
long x0, y0, z0;
long x1, y1, z1, z2, t;
// Checkstyle: resume
x0 = x & 0xFFFFFFFFL;
x1 = x >> 32;
y0 = y & 0xFFFFFFFFL;
y1 = y >> 32;
z0 = x0 * y0;
t = x1 * y0 + (z0 >>> 32);
z1 = t & 0xFFFFFFFFL;
z2 = t >> 32;
z1 += x0 * y1;
return x1 * y1 + z2 + (z1 >> 32);
}
/** @since 0.8 or earlier */
public static long multiplyHighUnsigned(long x, long y) {
// Checkstyle: stop
long x0, y0, z0;
long x1, y1, z1, z2, t;
// Checkstyle: resume
x0 = x & 0xFFFFFFFFL;
x1 = x >>> 32;
y0 = y & 0xFFFFFFFFL;
y1 = y >>> 32;
z0 = x0 * y0;
t = x1 * y0 + (z0 >>> 32);
z1 = t & 0xFFFFFFFFL;
z2 = t >>> 32;
z1 += x0 * y1;
return x1 * y1 + z2 + (z1 >>> 32);
}
}
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