ConditionCodes.C

#include <iostream>
#include <iomanip>
#include "ConditionCodes.h"
#include "Tools.h"

//cc_instance will be initialized to reference the single 
//instance of ConditionCodes
ConditionCodes * ConditionCodes::ccInstance = NULL;

/**
 * ConditionCodes constructor
 * initialize the codes field to 0
 */
ConditionCodes::ConditionCodes() {
	codes = 0;
}

/**
 * getInstance
 * if ccInstance is NULL then getInstance creates the
 * single ConditionCodes instance and sets ccInstance
 * to that. Otherwise, it returns ccInstance
 *
 * @return ccInstance
 */
ConditionCodes * ConditionCodes::getInstance() {
	if (ccInstance == NULL) ccInstance = new ConditionCodes();
	return ccInstance;
}

/*
 * getConditionCode
 * accepts a condition code number (OF, SF, or ZF) and returns 
 * the value of the condition code 
 *
 * @param ccNum equal to either OF, SF, or ZF
 * @return the value of bit ccNum out of codes. if ccNum is 
 *         out of range then returns false
 * @return error is set to true if ccNum is out of range and
 *         false otherwise
 */
bool ConditionCodes::getConditionCode(int32_t ccNum, bool & error) {
   	if (ccNum == ZF || ccNum == OF || ccNum == SF) {
		error = false;
		return Tools::getBits(codes, ccNum, ccNum);	
	}
	error = true;
	return false;	
}

/*
 * setConditionCode
 * accepts a condition code number (OF, SF, or ZF) and value
 * (true or false) and sets the condition code bit to that
 * value (1/true or 0/false). if the ccNum value is out of 
 * range then codes does not get modified. 
 *
 * @param value to set the condition code bit to (true/1 or false/0)
 * @param ccNum condition code number, either OF, SF, or ZF
 * @return error is set to true if ccNum is out of range and
 *         false otherwise
 */
void ConditionCodes::setConditionCode(bool value, int32_t ccNum, bool & error) {
	if (ccNum == ZF || ccNum == OF || ccNum == SF) {
		error = false;
		if (value) codes = Tools::setBits(codes, ccNum, ccNum);	
		else codes = Tools::clearBits(codes, ccNum, ccNum);	
	} else error = true;
}

/*
 * dump
 * outputs the values of the condition codes
 */
void ConditionCodes::dump() {
   int32_t zf = Tools::getBits(codes, ZF, ZF);
   int32_t sf = Tools::getBits(codes, SF, SF);
   int32_t of = Tools::getBits(codes, OF, OF);
   std::cout << std::endl;
   std::cout << "ZF: " << std::hex << std::setw(1) << zf << " ";
   std::cout << "SF: " << std::hex << std::setw(1) << sf << " ";
   std::cout << "OF: " << std::hex << std::setw(1) << of << std::endl;
}