code: /**
   * Copyright (c) 2004-2005, Regents of the University of California
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * Neither the name of the University of California, Los Angeles nor the
   * names of its contributors may be used to endorse or promote products
   * derived from this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  package jintgen.isdl;
  
  import cck.text.StringUtil;
  import cck.util.Util;
  import jintgen.isdl.parser.Token;
  import jintgen.jigir.Expr;
  import java.util.LinkedList;
  import java.util.List;
  
  /**
   * The <code>FormatDecl</code> class represents the encoding of an instruction in machine code, describing
   * how to encode the mnemonic and operands into binary and vice versa.
   *
   * @author Ben L. Titzer
   */
  public class FormatDecl extends Item {
  
      protected final int prio;
  
      public final List<BitField> fields;
  
      public int bitWidth = -1;
  
      protected Cond condition;
  
      public FormatDecl(Token n, Token pr, List<Expr> f) {
          super(n);
          fields = new LinkedList<BitField>();
          if ( f != null ) for ( Expr e : f ) {
              fields.add(new BitField(e));
          }
          if ( pr == null ) {
              prio = 0;
          } else {
              prio = StringUtil.evaluateIntegerLiteral(pr.image);
          }
      }
  
      public static class BitField {
          public final Expr field;
          public int width = -1;
          BitField(Expr f) {
              field = f;
          }
          public BitField(Expr f, int w) {
              field = f;
              width = w;
          }
          public int getWidth() {
              if ( width < 0 )
                  throw Util.failure("negative bit width");
              return width;
          }
      }
  
      public static class Cond {
          public final Token name;
          public final Expr expr;
  
          public Cond(Token n, Expr e) {
              name = n;
              expr = e;
          }
      }
  
      public static class Substitution {
          public final Token name;
          public final Expr expr;
  
          public Substitution(Token n, Expr e) {
              name = n;
              expr = e;
          }
      }
  
      public static class Derived extends FormatDecl {
          public final Token pname;
          public final List<Substitution> subst;
          public FormatDecl parent;
  
          public Derived(Token n, Token pr, Token p, List<Substitution> s) {
              super(n, pr, null);
              pname = p;
              subst = s;
          }
  
          public void setParent(FormatDecl p) {
              parent = p;
          }
  
          public int getBitWidth() {
              if (bitWidth < 0)
                  bitWidth = parent.getBitWidth();
              return bitWidth;
          }
  
      }
  
      public int getBitWidth() {
          return bitWidth;
      }
  
      public void setCond(Cond c) {
          condition = c;
      }
  
      public Cond getCond() {
          return condition;
      }
  
      public boolean isConditional() {
          return condition != null;
      }
  
      public int getPriority() {
          return prio;
      }
  }
  