/*
 * Copyright (c) 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.graal.snippets;

import com.oracle.graal.api.code.RuntimeCallTarget.Descriptor;
import com.oracle.graal.graph.Node.ConstantNodeParameter;
import com.oracle.graal.graph.Node.NodeIntrinsic;
import com.oracle.graal.nodes.extended.*;
import com.oracle.graal.snippets.ClassSubstitution.MethodSubstitution;
import com.oracle.graal.snippets.nodes.*;
import com.oracle.graal.snippets.nodes.MathIntrinsicNode.Operation;

/**
 * Substitutions for {@link java.lang.Math} methods.
 */
@ClassSubstitution(java.lang.Math.class)
public class MathSubstitutionsX86 {

    private static final double PI_4 = 0.7853981633974483;

    @MethodSubstitution
    public static double abs(double x) {
        return MathIntrinsicNode.compute(x, Operation.ABS);
    }

    @MethodSubstitution
    public static double sqrt(double x) {
        return MathIntrinsicNode.compute(x, Operation.SQRT);
    }

    @MethodSubstitution
    public static double log(double x) {
        return MathIntrinsicNode.compute(x, Operation.LOG);
    }

    @MethodSubstitution
    public static double log10(double x) {
        return MathIntrinsicNode.compute(x, Operation.LOG10);
    }

    // NOTE on snippets below:
    // Math.sin(), .cos() and .tan() guarantee a value within 1 ULP of the
    // exact result, but x87 trigonometric FPU instructions are only that
    // accurate within [-pi/4, pi/4]. Examine the passed value and provide
    // a slow path for inputs outside of that interval.

    @MethodSubstitution
    public static double sin(double x) {
        if (abs(x) < PI_4) {
            return MathIntrinsicNode.compute(x, Operation.SIN);
        } else {
            return callDouble(ARITHMETIC_SIN, x);
        }
    }

    @MethodSubstitution
    public static double cos(double x) {
        if (abs(x) < PI_4) {
            return MathIntrinsicNode.compute(x, Operation.COS);
        } else {
            return callDouble(ARITHMETIC_COS, x);
        }
    }

    @MethodSubstitution
    public static double tan(double x) {
        if (abs(x) < PI_4) {
            return MathIntrinsicNode.compute(x, Operation.TAN);
        } else {
            return callDouble(ARITHMETIC_TAN, x);
        }
    }

    public static final Descriptor ARITHMETIC_SIN = new Descriptor("arithmeticSin", false, double.class, double.class);
    public static final Descriptor ARITHMETIC_COS = new Descriptor("arithmeticCos", false, double.class, double.class);
    public static final Descriptor ARITHMETIC_TAN = new Descriptor("arithmeticTan", false, double.class, double.class);

    @NodeIntrinsic(value = RuntimeCallNode.class, setStampFromReturnType = true)
    public static native double callDouble(@ConstantNodeParameter
    Descriptor descriptor, double value);
}