Machine Code Generation

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🎯 Aim

To develop a compiler phase that converts a given infix arithmetic expression into:

1. Postfix notation (Reverse Polish Notation),
2. Quadruples (Intermediate Code Representation),
3. Three-Address / Machine Code.

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🧠 Explanation

This program simulates the backend phase of a compiler, which is responsible for generating intermediate and target code from a high-level expression. It performs:

• Conversion from infix to postfix using operator precedence and a stack.
• Generation of quadruples, a standard intermediate representation in compilers using temporary variables.
• Creation of Three-Address Code (TAC) or Machine code-like instructions for arithmetic operations.

This process mirrors how a real compiler breaks down high-level arithmetic into machine-executable code.

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🔁 Logic

Step-by-step Process:

1. Infix to Postfix Conversion:

   • Use a stack to manage operators and apply precedence rules to form the postfix expression.

2. Quadruple Generation:

   • Traverse the postfix expression.
   • For each operator, pop the top two operands, apply the operation, and store the result in a temporary variable t1, t2....

3. Three-Address Code (TAC) / Machine Code Generation:

   • For each operation, generate equivalent low-level instructions:
     • Use MOV, ADD, MUL, and POW instructions for computation.
     • Results are stored in temporaries and finally assigned to a variable a.

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📥 Sample Input & Output

✅ Input

Input an expression: a+b*c

🔁 Output

Postfix Expression: abc*+

Quadruples:
(+, a, t1, t2)
(*, b, c, t1)

Three-Address Code/Machine Code:
MOV b, R0
MUL c, R0
MOV R0, t1
MOV a, R0
ADD t1, R0
MOV R0, t2
MOV t2, a

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🌐 Real-World Applications

• Compiler Construction: Forms the core of backend phases in compilers like GCC or Clang.
• Virtual Machines: Used in interpreters like Python (CPython) or JVM to generate bytecode.
• Code Optimisation Tools: Intermediate representations, such as quadruples, are used for optimisation passes.
• Static Analysis Tools: These tools utilise such representations to detect bugs, inefficiencies, or vulnerabilities.

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