Assembler Project in C

📌 Overview

This project is an **assembler written in C, developed as part of a university course. The assembler reads assembly source files (.as) and produces the corresponding machine code and supporting output files. It implements a two-pass process (first pass & second pass) for symbol resolution and code generation.

🛠 Features

• Pre-assembler stage (macro handling and preprocessing).
• First pass for symbol table creation and label detection.
• Second pass for encoding instructions and resolving references.
• Support for external and entry symbols.
• Generates output files:
  • .ob – Object file (machine code).
  • .ent – Entry symbols.
  • .ext – External symbols.

📂 Project Structure

project/
├── encoding.c / encoding.h
├── first_pass.c / first_pass.h
├── second_pass.c / second_pass.h
├── pre_assembler.c / pre_assembler.h
├── define_variable.c / define_variable.h
├── data.c / data.h
├── makefile
├── ps.as          # Example input file
├── ps.ob          # Example object output
├── ps.ent / ps.ext# Example symbol outputs
└── ...

⚡ Compilation

Use the provided makefile to build the project:

make

This will compile all modules and generate the assembler executable.

To clean build files:

make clean

▶️ Usage

Run the assembler with an assembly source file:

./assembler ps.as

This will produce .ob, .ent, and .ext files as output.

🧪 Example

Input file (ps.as):

; sample assembly file
MAIN:   mov r3, LENGTH
        add r2,
         r3
        stop
LENGTH: .data 6

Output files include:

• ps.ob (object code)
• ps.ent (entries)
• ps.ext (externals, if used)

📚 Skills Gained

• Low-level programming in C
• Modular software design
• Understanding of assembler internals and machine code translation
• Working with symbol tables and memory management