DefineWordDirective.java

/*
  DefineWordDirective.java

  (c) 2008-2013 Edward Swartz

  All rights reserved. This program and the accompanying materials
  are made available under the terms of the Eclipse Public License v1.0
  which accompanies this distribution, and is available at
  http://www.eclipse.org/legal/epl-v10.html
 */
package v9t9.tools.asm.directive;

import java.util.List;
import java.util.ListIterator;

import v9t9.common.asm.IInstruction;
import v9t9.common.asm.ResolveException;
import v9t9.tools.asm.IAsmInstructionFactory;
import v9t9.tools.asm.IAssembler;
import v9t9.tools.asm.operand.hl.AssemblerOperand;
import v9t9.tools.asm.operand.ll.LLForwardOperand;
import v9t9.tools.asm.operand.ll.LLImmedOperand;
import v9t9.tools.asm.operand.ll.LLOperand;

/**
 * @author Ed
 *
 */
public class DefineWordDirective extends Directive {

	private List<AssemblerOperand> ops;

	public DefineWordDirective(List<AssemblerOperand> ops) {
		this.ops = ops;
	}
	
	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder();
		builder.append("DW ");
		boolean first = true;
		for (AssemblerOperand op : ops) {
			if (first)
				first = false;
			else
				builder.append(", ");
			builder.append(op.toString());
		}			
		return builder.toString();
	}

	public IInstruction[] resolve(IAssembler assembler, IInstruction previous, boolean finalPass) throws ResolveException {
		assembler.setPc((assembler.getPc() + 1) & 0xfffe);
		setPc(assembler.getPc());

		
		for (ListIterator<AssemblerOperand> iterator = ops.listIterator(); iterator.hasNext();) {
			AssemblerOperand op = iterator.next();
			LLOperand lop = op.resolve(assembler, this); 
			if (!(lop instanceof LLForwardOperand)) {
				if (!(lop instanceof LLImmedOperand))
					throw new ResolveException(op, "Expected number");
			}
			iterator.set(lop);
			assembler.setPc(assembler.getPc() + 2);
		}
		return new IInstruction[] { this };
	}
	
	public byte[] getBytes(IAsmInstructionFactory factory) throws ResolveException {
		byte[] bytes = new byte[ops.size() * 2];
		int idx = 0;
		for (AssemblerOperand op : ops) {
			if (op instanceof LLForwardOperand)
				throw new ResolveException(op);
			LLOperand lop = (LLOperand) op;
			if (!(lop instanceof LLImmedOperand))
				throw new ResolveException(op, "Expected number");
			bytes[idx++] = (byte) (lop.getImmediate() >> 8);
			bytes[idx++] = (byte) (lop.getImmediate() & 0xff);
		}
		return bytes;
	}
	

}