CPU-Processor-Simulator/ALU.java at main · Harri1118/CPU-Processor-Simulator · GitHub

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public class ALU {
    // Final variables paired different values for the ALU instruction to perform
    private static final Bit TRUE = new Bit(true);
    private static final Bit FALSE = new Bit(false);
    private static final Word16 ADD_NUM = new Word16(new Bit[]{FALSE, FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 AND = new Word16(new Bit[]{FALSE, FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 MULTIPLY_NUM = new Word16(new Bit[]{FALSE, FALSE, FALSE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 LEFT_SHIFT = new Word16(new Bit[]{FALSE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 SUBTRACT_NUM = new Word16(new Bit[]{FALSE, FALSE, TRUE, FALSE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 OR = new Word16(new Bit[]{FALSE, FALSE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    private static final Word16 RIGHT_SHIFT = new Word16(new Bit[]{FALSE, FALSE, TRUE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    public static final Word16 COMPARE = new Word16(new Bit[]{FALSE, TRUE, FALSE, TRUE, TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE});
    // Built vals for ALU.
    public Word16 instruction = new Word16();
    public Word32 op1 = new Word32();
    public Word32 op2 = new Word32();
    public Word32 result = new Word32();
    public Bit less = new Bit(false);
    public Bit equal = new Bit(false);
    // doInstruction handles any arithmetic involving variables instruction, op1, and op2
    public void doInstruction(){
        // Handle adding
        if(instruction.equals(ADD_NUM,5)){
            Word32 fNum = new Word32();
            Word32 sNum = new Word32();
            op1.copy(fNum);
            op2.copy(sNum);
            Adder.add(fNum, sNum, result);
        }
        // Handle and
        else if(instruction.equals(AND,5))
            op1.and(op2, result);
        // Handle multiplication
        else if(instruction.equals(MULTIPLY_NUM,5)){
            Word32 fNum = new Word32();
            Word32 sNum = new Word32();
            op1.copy(fNum);
            op2.copy(sNum);
            Multiplier.multiply(fNum, sNum, result);
        }
        // Handle left shifting
        else if(instruction.equals(LEFT_SHIFT,5)){
            // Create copies of op1 and op2, subtract from op2 by 1 and leftshift by 1
            // the op1Fin. After op2 amount of times of being leftshifted, set it to result.
            Word32 one = new Word32();
            one.setBitN(31, new Bit(true));
            Word32 op1Fin = new Word32();
            op1.copy(op1Fin);
            Word32 iterator = new Word32();
            op2.copy(iterator);
            while(!iterator.equals(new Word32())){
                Shifter.LeftShift(op1Fin, 1, op1Fin);
                Word32 cp = new Word32();
                iterator.copy(cp);
                Adder.subtract(cp, one, iterator);
            }
            op1Fin.copy(result);
        }
        // Handle subtracting
        else if(instruction.equals(SUBTRACT_NUM,5))
            Adder.subtract(op1, op2, result);
        // Handle OR
        else if(instruction.equals(OR,5))
            op1.or(op2, result);
        // Handle right shifting
        else if(instruction.equals(RIGHT_SHIFT,5)){
            // Create copies of op1 and op2, subtract from op2 by 1 and rightshift by 1
            // the op1Fin. After op2 amount of times of being rightshifted, set it to result.
            Word32 one = new Word32();
            one.setBitN(31, new Bit(true));
            Word32 op1Fin = new Word32();
            op1.copy(op1Fin);
            Word32 iterator = new Word32();
            op2.copy(iterator);
            while(!iterator.equals(new Word32())){
                Shifter.RightShift(op1Fin, 1, op1Fin);
                Word32 cp = new Word32();
                iterator.copy(cp);
                Adder.subtract(cp, one, iterator);
            }
            op1Fin.copy(result);
        }
        // Handle comparing
        else if(instruction.equals(COMPARE,5)) {
            // Account for negative numbers
            Bit a = new Bit(false);
            Bit b = new Bit(false);
            op1.getBitN(0, a);
            op2.getBitN(0, b);
            if (a.getValue() == Bit.boolValues.TRUE && b.getValue() == Bit.boolValues.FALSE){
                less.assign(Bit.boolValues.TRUE);
                equal.assign(Bit.boolValues.FALSE);
            }
            else if (a.getValue() == Bit.boolValues.FALSE && b.getValue() == Bit.boolValues.TRUE) {
                less.assign(Bit.boolValues.FALSE);
                equal.assign(Bit.boolValues.FALSE);
            }
            else{
            // Subtract op1 and op2 and set to res
            Word32 res = new Word32();
            Adder.subtract(op1, op2, res);
            // If res is 0 then set equal to true and less to false
            if (res.equals(new Word32())) {
                less.assign(Bit.boolValues.FALSE);
                equal.assign(Bit.boolValues.TRUE);
            }
            // Else, check if res is positive or negative. If negative then
            // set equal to false and less to true, else set equal to false and
            // res to false.
            else {
                Bit checkNegBit = new Bit(false);
                res.getBitN(0, checkNegBit);
                if (checkNegBit.getValue() == Bit.boolValues.TRUE) {
                    less.assign(Bit.boolValues.TRUE);
                    equal.assign(Bit.boolValues.FALSE);
                } else {
                    less.assign(Bit.boolValues.FALSE);
                    equal.assign(Bit.boolValues.FALSE);
                }
            }
        }
        }
        else{
            System.out.println("Error!");
        }

    }
}