JWebAssembly/src/de/inetsoftware/jwebassembly/module/WasmNumericInstruction.java

/*
   Copyright 2018 - 2019 Volker Berlin (i-net software)

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

*/
package de.inetsoftware.jwebassembly.module;

import java.io.IOException;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import de.inetsoftware.jwebassembly.module.WasmInstruction.Type;
import de.inetsoftware.jwebassembly.wasm.AnyType;
import de.inetsoftware.jwebassembly.wasm.NumericOperator;
import de.inetsoftware.jwebassembly.wasm.ValueType;

/**
 * WasmInstruction for numeric operation.
 * 
 * @author Volker Berlin
 *
 */
class WasmNumericInstruction extends WasmInstruction {

    NumericOperator         numOp;

    private final ValueType valueType;

    /**
     * Create an instance of numeric operation.
     * 
     * @param numOp
     *            the numeric operation
     * @param valueType
     *            the type of the parameters
     * @param javaCodePos
     *            the code position/offset in the Java method
     */
    WasmNumericInstruction( @Nullable NumericOperator numOp, @Nullable ValueType valueType, int javaCodePos ) {
        super( javaCodePos );
        this.numOp = numOp;
        this.valueType = valueType;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    Type getType() {
        return Type.Numeric;
    }

    /**
     * {@inheritDoc}
     */
    public void writeTo( @Nonnull ModuleWriter writer ) throws IOException {
        writer.writeNumericOperator( numOp, valueType );
    }

    /**
     * {@inheritDoc}
     */
    AnyType getPushValueType() {
        switch( numOp ) {
            case eq:
            case ne:
            case gt:
            case lt:
            case le:
            case ge:
                return null;
            default:
                return valueType;
        }
    }

    /**
     * {@inheritDoc}
     */
    @Override
    int getPopCount() {
        switch( numOp ) {
            case neg:
                return 1;
            default:
                return 2;
        }
    }
}