ToMachine

/*
 *  Please don't give empty lines in code  else scanning exception will occur(NoSuchElementException)
 *  movi --> can take max immediate value =511
 *  mov1i will put immediate value in register 1 
 *  register no. 7 is used as jump register
 *  Only first 64 locations are for memory, rest are used by stack pointer
 *  SLT r1,r2   compares r1 and r2 ,if val(r1) < val(r2) then r0 =1,else r0=0
 *  beq  label      check the contents of r0 , if val(r0) = 1 then goto label 
 */

package coa_pipelining;

import java.util.NoSuchElementException;
import java.util.Scanner;

public class ToMachine {
	
	static label[] labels =null;
	static  int lAdd = 0 ;
	static int lCount = 0;

	public String AssemblyToMachine(String str) {
		str = str.toUpperCase();
		
		Scanner in = new Scanner(str);
		
		String opcode = in.next();		
		
		String restCode = "";
		try{
			restCode = in.nextLine();
		}catch(NoSuchElementException e){
			
		}
		in.close();
		return AssemblyDecoder(opcode, restCode);

	}

	private String AssemblyDecoder(String opcode, String restCode) {
		
		Scanner in1 = new Scanner(restCode);
		String machineIns = "";
		int[] op = new int[3];
		switch (opcode) {

		case "ADD":
		case "SUB":
		case "MUL":
		case "DIV":
			if (opcode.contentEquals("ADD"))
				machineIns += "0000";
			if (opcode.contentEquals("SUB"))
				machineIns += "0001";
			if (opcode.contentEquals("MUL"))
				machineIns += "0010";
			if (opcode.contentEquals("DIV"))
				machineIns += "0011";

			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			op[2] = in1.nextInt();
			for (int i = 0; i < 3; i++)
				machineIns += deciToBinary(op[i], 3); // Second argument is to
														// take output in 3
														// digits
			machineIns += "000";
			break;

		case "SLL":
		case "SLR":
			if (opcode.contentEquals("SLL"))
				machineIns += "0100";
			if (opcode.contentEquals("SLR"))
				machineIns += "0101";

			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			op[2] = in1.nextInt();
			for (int i = 0; i < 2; i++)
				machineIns += deciToBinary(op[i], 3);
			machineIns += deciToBinary(op[2], 6);// Second argument is to take
													// output in 3 digits

			break;

		case "MOV1I":
			machineIns += "0110";
			int val = in1.nextInt();
			machineIns += deciToBinary(val, 12);
			break;
			
		case "JMP":
		case "JAL":
		case "BEQ":
			if(opcode.contentEquals("JMP"))machineIns+="0111";
			if(opcode.contentEquals("JAL"))machineIns+="1000";
			if(opcode.contentEquals("BEQ"))machineIns+="1110";
			String label = in1.next();
			int addValue = lAdd;
			for(int ii=0;ii<lCount;ii++){				
				if(labels[ii].lName.contentEquals(label))
				{
					addValue=labels[ii].lAddress;
					break;
					
				}
			}
			machineIns+=deciToBinary(addValue, 12);
			break;

			
			
		case "MOVR":
			machineIns += "1001";
			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			for (int i = 0; i < 2; i++)
				machineIns += deciToBinary(op[i], 3);
			machineIns += "000000";
			break;

		case "MOVI":
			machineIns += "1010";
			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			machineIns += deciToBinary(op[0], 3);
			machineIns += deciToBinary(op[1], 9);
			break;

		case "JR":
			machineIns += "1011";
			op[0] = in1.nextInt();
			machineIns += deciToBinary(op[0], 3);
			machineIns += deciToBinary(0, 9);
			break;
			
		case "LD":
		case "ST":
			if(opcode.contentEquals("LD"))machineIns+="1100";
			if(opcode.contentEquals("ST"))machineIns+="1101";
			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			machineIns+=deciToBinary(op[0], 3);
			machineIns+=deciToBinary(op[1], 6);
			machineIns+="000";
			break;
		
			
		case "SLT":
			machineIns+="1111";
			op[0] = in1.nextInt();
			op[1] = in1.nextInt();
			machineIns+=deciToBinary(op[0], 3);
			machineIns+=deciToBinary(op[1], 3);
			machineIns+="000000";
			break;
			
			
		 default:
			 
			 machineIns+=deciToBinary(65535,16);   // whole instruction consist of 1's only
			 break;
		
		}
		in1.close();
		return machineIns;
	}

	private String deciToBinary(int i, int j) {
		// TODO Auto-generated method stub
		String str = "";
		int n = Integer.toBinaryString(i).length();
		for (int ii = 0; ii < j - n; ii++)
			str += "0";
		str += Integer.toBinaryString(i);
		return str;
	}

	public void fillLabels(String str) {
		// TODO Auto-generated method stub
		lAdd++;
		str = str.toUpperCase();
		Scanner ume = new Scanner(str);
		String opcode="",restcode="";
		opcode = ume.next();
		try{
			restcode = ume.nextLine();
		}catch(NoSuchElementException e){
			restcode="";
		}
		if(restcode.contentEquals(""))
		{
			labels[lCount] = new label();
			 labels[lCount].lName=opcode;
			 labels[lCount].lAddress=lAdd;
			 lCount++;	
		}
		ume.close();
	}
}


class label {
	String lName;
	int lAddress;
}