001    /*
002     *  This file is part of the Jikes RVM project (http://jikesrvm.org).
003     *
004     *  This file is licensed to You under the Eclipse Public License (EPL);
005     *  You may not use this file except in compliance with the License. You
006     *  may obtain a copy of the License at
007     *
008     *      http://www.opensource.org/licenses/eclipse-1.0.php
009     *
010     *  See the COPYRIGHT.txt file distributed with this work for information
011     *  regarding copyright ownership.
012     */
013    package org.jikesrvm.compilers.baseline;
014    
015    /**
016     * A set of constants that define some useful Java types and stack
017     * sizes that describe the state of a basic block and its stack
018     * contents on entry.
019     */
020    public interface BBConstants {
021    
022      // first two bits determine the number of Java words making up the
023      // entity
024      byte LENGTH_MASK = 0x03;
025    
026      byte VOID_TYPE = 0x00;
027      byte INT_TYPE = 0x01;
028      byte ADDRESS_TYPE = 0x02;
029      byte LONG_TYPE = 0x04;
030      byte FLOAT_TYPE = 0x08;
031      byte DOUBLE_TYPE = 0x10;
032      byte LONGHALF_TYPE = 0x20;
033    
034      short DUMMYBLOCK = -1;
035      short STARTBLOCK = 1;
036      short EXITBLOCK = 2;
037      short EXCEPTIONHANDLER = -2;
038    
039      byte TARGET_ = 0x10;
040      byte CONDITIONAL_ = 0x20;
041      byte FALLTHRU_ = 0x40;
042      byte TRYSTART_ = (byte) 0x80;
043    
044      byte NOTBLOCK = 0x0;
045      byte INJSR_ = 0x1;
046      byte JSRENTRY = 0x2;
047      byte TRYHANDLERSTART = 0x4;
048      byte HASHANDLER_ = 0x8;
049      byte METHODENTRY = TARGET_;
050      byte CONDITIONALTARGET = TARGET_ | CONDITIONAL_;
051      byte UNCONDITIONALTARGET = TARGET_;
052      byte FALLTHRUTARGET = TARGET_ | CONDITIONAL_ | FALLTHRU_;
053    
054    }