001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.commons.nabla.forward.instructions;
018
019 import org.apache.commons.nabla.DifferentiationException;
020 import org.apache.commons.nabla.forward.analysis.InstructionsTransformer;
021 import org.apache.commons.nabla.forward.analysis.MethodDifferentiator;
022 import org.objectweb.asm.Opcodes;
023 import org.objectweb.asm.Type;
024 import org.objectweb.asm.tree.AbstractInsnNode;
025 import org.objectweb.asm.tree.InsnList;
026 import org.objectweb.asm.tree.InsnNode;
027 import org.objectweb.asm.tree.MethodInsnNode;
028
029 /** Differentiation transformer for DCMPx instructions.
030 * @version $Id$
031 */
032 public class DcmpTransformer implements InstructionsTransformer {
033
034 /** Name of the {@link org.apache.commons.math3.analysis.differentiation.DerivativeStructure} method corresponding to the value getter. */
035 private static final String VALUE_GETTER_METHOD = "getValue";
036
037 /** Indicator for top stack element conversion. */
038 private final boolean stack0Converted;
039
040 /** Indicator for next to top stack element conversion. */
041 private final boolean stack1Converted;
042
043 /** Simple constructor.
044 * @param stack0Converted if true, the top level stack element has already been converted
045 * @param stack1Converted if true, the next to top level stack element has already been converted
046 */
047 public DcmpTransformer(final boolean stack0Converted, final boolean stack1Converted) {
048 this.stack0Converted = stack0Converted;
049 this.stack1Converted = stack1Converted;
050 }
051
052 /** {@inheritDoc} */
053 public InsnList getReplacement(final AbstractInsnNode insn,
054 final MethodDifferentiator methodDifferentiator)
055 throws DifferentiationException {
056 final InsnList list = new InsnList();
057
058 if (stack1Converted) {
059 if (stack0Converted) {
060 // operand stack initial state: ds_a, ds_b
061 list.add(new InsnNode(Opcodes.SWAP)); // => ds_b, ds_a
062 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
063 VALUE_GETTER_METHOD,
064 Type.getMethodDescriptor(Type.DOUBLE_TYPE))); // => ds_b, a0
065 list.add(new InsnNode(Opcodes.DUP2_X2)); // => a0, ds_b, a0
066 list.add(new InsnNode(Opcodes.POP2)); // => a0, ds_b
067 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
068 VALUE_GETTER_METHOD,
069 Type.getMethodDescriptor(Type.DOUBLE_TYPE))); // => a0, b0
070 } else {
071 // operand stack initial state: ds_a, b0
072 list.add(new InsnNode(Opcodes.DUP2_X2)); // => b0, ds_a, b0
073 list.add(new InsnNode(Opcodes.POP2)); // => b0, ds_a
074 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
075 VALUE_GETTER_METHOD,
076 Type.getMethodDescriptor(Type.DOUBLE_TYPE))); // => b0, a0
077 list.add(new InsnNode(Opcodes.DUP2_X2)); // => a0, b0, a0
078 list.add(new InsnNode(Opcodes.POP2)); // => a0, b0
079 }
080 } else {
081 // operand stack initial state: a, ds_b
082 list.add(new MethodInsnNode(Opcodes.INVOKEVIRTUAL, DS_TYPE.getInternalName(),
083 VALUE_GETTER_METHOD,
084 Type.getMethodDescriptor(Type.DOUBLE_TYPE))); // => a0, b0
085 }
086
087 list.add(new InsnNode(insn.getOpcode())); // => bool
088
089 return list;
090
091 }
092
093 }