Pass II Assembler Implementation

Problem Statement

Implement Pass-II of two pass assembler for pseudo-machine in Java/C++ using object oriented features. The output of assignment-1 (intermediate file, literal table and symbol table) should be input for this assignment.

Java Code Implementation

import java.util.*;

public class pass2 {

    public static void main(String[] args) {
        // ----------------- SYMBOL TABLE -----------------
        Map symbolTable = new HashMap<>();
        symbolTable.put(0, new ST(0, "ONE", 205));
        symbolTable.put(1, new ST(1, "TWO", 209));
        symbolTable.put(2, new ST(2, "RESULT", 210));

        // ----------------- LITERAL TABLE ----------------
        Map literalTable = new HashMap<>();
        literalTable.put(0, new LT(0, "='5'", 211));
        literalTable.put(1, new LT(1, "='3'", 212));

        // ----------------- INTERMEDIATE CODE -------------
        String[] intermediateCode = {
            "AD 01 C 200",
            "IS 04 RG 1 S 0",
            "IS 01 RG 2 S 1",
            "IS 01 RG 2 L 0",
            "IS 05 RG 3 S 2",
            "IS 01 RG 2 L 1",
            "DL 01 C 4",
            "DL 02 C 2",
            "DL 01 C 1",
            "AD 02",
            "DL 02 C 5",
            "DL 02 C 3"
        };

        System.out.println("Final Machine Code:");
        System.out.println("-------------------");

        for (String line : intermediateCode) {
            String tokens[] = line.split("[ ,]+");
 
            // IS 04 RG 1 S 0   //  04 1 205
            
            String token_opcodeClass   = tokens[0]; // AD, IS, DL  //IS
            String token_opcode        = tokens.length > 1 ? tokens[1] : null; //04
            String token_operand1Type  = tokens.length > 2 ? tokens[2] : null; // RG
            String token_operand1      = tokens.length > 3 ? tokens[3] : null; // 1
            String token_operand2Type  = tokens.length > 4 ? tokens[4] : null; //S
            String token_operand2      = tokens.length > 5 ? tokens[5] : null;  //0

            // ---- Process Imperative Statements ----
            if ("IS".equals(token_opcodeClass)) {
                System.out.print(token_opcode + " ");

                // Operand 1: Register
                if ("RG".equals(token_operand1Type)) {
                    System.out.print(token_operand1 + " ");
                }

                // Operand 2: Symbol
                if ("S".equals(token_operand2Type)) {
                    ST sym = symbolTable.get(Integer.parseInt(token_operand2));
                    System.out.print(sym.address);
                }

                // Operand 2: Literal
                if ("L".equals(token_operand2Type)) {
                    LT lit = literalTable.get(Integer.parseInt(token_operand2));
                    System.out.print(lit.address);
                }

                System.out.println();
            }

            // ---- Process Declarative Statements ----
            else if ("DL".equals(token_opcodeClass)) {
                if ("01".equals(token_opcode)) { // DC
                    System.out.println("00 0 " + token_operand1);
                }
                if ("02".equals(token_opcode)) { // DS
                   // System.out.println("00 0 " + "0".repeat(Integer.parseInt(token_operand1)));
                     System.out.println("00 0 " + token_operand1);
                }
            }

            // ---- Assembler Directives (AD) - no machine code ----
            else if ("AD".equals(token_opcodeClass)) {
                continue;
            }
        }

        // ----------------- Print Symbol & Literal Tables -----------------
        System.out.println("\nSYMBOL TABLE:");
        for (ST s : symbolTable.values()) {
            System.out.println(s.index + "\t" + s.name + "\t" + s.address);
        }

        System.out.println("\nLITERAL TABLE:");
        for (LT l : literalTable.values()) {
            System.out.println(l.index + "\t" + l.Literal + "\t" + l.address);
        }
    }
}

Output

Final Machine Code:
-------------------
04 1 205
01 2 209
01 2 211
05 3 210
01 2 212
00 0 4
00 0 2
00 0 1
00 0 5
00 0 3

SYMBOL TABLE:
0	ONE	205
1	TWO	209
2	RESULT	210

LITERAL TABLE:
0	='5'	211
1	='3'	212