Full Adder and Half Adder

package com.johnny.adder;

/**
 *
 * @author johnny
 */
public class Adder {

static public AdderResult halfAdder(int a, int b) {
return new AdderResult(a ^ b, a & b);
}

static public AdderResult fullAdder(int a, int b, int carryIn) {
AdderResult res1 = halfAdder(a, b);
AdderResult res2 = halfAdder(res1.getSum(), carryIn);

return new AdderResult(res2.getSum(), res1.getCarry() | res2.getCarry());
}

}

package com.johnny.adder;

/**

 *

 * @author johnny

 */

public class AdderResult {

private int sum;

private int carry;

public AdderResult(int sum, int carry) {

this.sum = sum;

this.carry = carry;

}

public int getSum() {

return sum;

}

public void setSum(int sum) {

this.sum = sum;

}

public int getCarry() {

return carry;

}

public void setCarry(int carry) {

this.carry = carry;

}

@Override

public String toString() {

return " sum " + getSum() + " carry " + getCarry();

}

}

package com.johnny.adder;

import com.johnny.app.AppException;

import com.johnny.app.AppInf;

import java.util.logging.Level;

import java.util.logging.Logger;

/**

 *

 * @author johnny

 */

public class App implements AppInf {

@Override

public String getTitle() {

return "Full Adder";

}

@Override

public void execute(String[] args) {

assertAdder(Adder.fullAdder(0, 0, 0), 0, 0);

assertAdder(Adder.fullAdder(0, 1, 0), 1, 0);

assertAdder(Adder.fullAdder(1, 0, 0), 1, 0);

assertAdder(Adder.fullAdder(1, 1, 0), 0, 1);

assertAdder(Adder.fullAdder(0, 0, 1), 1, 0);

assertAdder(Adder.fullAdder(0, 1, 1), 0, 1);

assertAdder(Adder.fullAdder(1, 0, 1), 0, 1);

assertAdder(Adder.fullAdder(1, 1, 1), 1, 1);

for (int i = -8192; i < 8192; i++) {

for (int j = -8192; j < 8192; j++) {

try {

assertCond((add(i, j) == (i + j)), " sum failed " + i + "+" + j);

} catch (Exception ex) {

Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);

}

}

}

}

public int add(int a, int b) {

int sum = 0;

int carryIn = 0;

//for each bit do fullAdder

for (int bitNumber = 0; bitNumber < 32; bitNumber++) {

if (a == 0 && b == 0 && carryIn == 0) {

break;

}

int abit = a & 1;

int bbit = b & 1;

AdderResult res = Adder.fullAdder(abit, bbit, carryIn);

sum |= (res.getSum() << bitNumber);

carryIn = res.getCarry();

a >>= 1;

b >>= 1;

}

return sum;

}

public void assertAdder(AdderResult result, int expectedSum, int expectedCarry) {

try {

assertCond(result.getSum() == expectedSum, "Sum not expected " + expectedSum + ":" + expectedCarry);

assertCond(result.getCarry() == expectedCarry, "Carry not expected " + expectedSum + ":" + expectedCarry);

} catch (AppException ex) {

Logger.getLogger(App.class.getName()).log(Level.SEVERE, null, ex);

}

}

public void assertCond(boolean condition, String failMessage) throws AppException {

if (!condition) {

throw new AppException(failMessage);

}

}

}