ContextSwitchRoutine.java

/*
  ContextSwitchRoutine.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.machine.ti99.asm;

import v9t9.common.asm.Block;
import v9t9.common.asm.IHighLevelInstruction;
import v9t9.common.asm.IMachineOperand;
import v9t9.common.asm.Routine;
import v9t9.machine.ti99.cpu.Inst9900;
import v9t9.machine.ti99.cpu.MachineOperand9900;

public class ContextSwitchRoutine extends Routine {
    private short wp;
    public ContextSwitchRoutine(int wp) {
        super();
        this.setWp((short) wp);
    }

    @Override
    public boolean isReturn(IHighLevelInstruction inst) {
        return inst.getInst().getInst() == Inst9900.Irtwp;
    }

    @Override
    public void examineEntryCode() {
        // TODO: look for stuff like LWPI
    	
    	dataWords = 0;
    	
    	int entryDataBytes = 0;
    	
    	for (Block block : getEntries()) {
    		IHighLevelInstruction inst = block.getFirst();
    		entryDataBytes = 0;
	        while (inst != null && !inst.isCall()) {
	        	// look for uses of parameter words; ignore any branching
	        	if (inst.getInst().getOp1() instanceof IMachineOperand) {
	                MachineOperand9900 mop1 = (MachineOperand9900) inst.getInst().getOp1();
	                if (mop1.isMemory() && mop1.type == MachineOperand9900.OP_INC 
	                        && mop1.val == 14) {
	                	if ((inst.getFlags() & HighLevelInstruction.fByteOp) != 0) {
	                		entryDataBytes++;
	                	} else {
	                		entryDataBytes += 2;
	                	}
	                }
	        	}
	        	
	            if (inst == block.getLast())
	            	break;
	            inst = inst.getLogicalNext();
	        }
	        
	        if (entryDataBytes / 2 > dataWords) {
	        	dataWords = entryDataBytes / 2;
	        }
    	}
    	
        if (dataWords > 0) {
			System.out.println("call site " + this + " seems to use " + dataWords + " data words");
		}
        
    }

	public void setWp(short wp) {
		this.wp = wp;
	}

	public short getWp() {
		return wp;
	}

}