EASM — Eren's Educational 2-Pass Assembler

EASM is an educational project that demonstrates the inner workings of a simple two-pass assembler.
It’s designed to help students and hobbyists learn about assembler structure, symbol resolution, and code generation using the GNU toolchain.

⚠️ Note: This project is educational and work in progress.

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📘 Overview

An assembler translates human-readable assembly language into machine code.
A two-pass assembler first scans the source to collect symbols and labels, then generates final machine code in the second pass.

EASM is not intended as a production assembler, but as an educational resource for understanding:

• How instruction parsing and tokenization work
• How symbol tables and relocations are handled
• How code is emitted after symbol resolution

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🧠 Features

• Two-pass parsing and symbol table management
• Basic instruction and directive recognition
• Minimal, clear code aimed at readability and learning
• Written in C/C++ using the GNU toolchain (gcc, g++)
• Cross-platform build system using make
• Compatible with Windows (MSYS2 / MinGW) and Linux

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⚙️ Building the Project

Clone the repository and build using GNU Make:

git clone https://github.com/herenturker/easm.git
cd easm
make

This command will compile all source files and produce the executable:

easm.exe    # On Windows
./easm      # On Linux

Requirements

You will need:

• GCC (C and C++ compilers)
• GNU Make
• Optionally MSYS2 or MinGW if you are on Windows

To verify installation:

gcc --version
g++ --version
make --version

By default, EASM reads the input assembly file and performs two passes:

1. Pass 1: Scans for labels, directives, and builds the symbol table
2. Pass 2: Resolves symbols and emits the final binary output

Runtime Dependencies

When compiled with GCC, the generated binary may depend on these runtime libraries:

DLL	Source	License	AGPL Compatibility
libgcc_s_seh-1.dll	GCC runtime	GPL + linking exception	Yes
libstdc++-6.dll	GNU C++ standard library	GPL + linking exception	Yes
KERNEL32.dll	Windows API	System component	Yes
msvcrt.dll	Microsoft C runtime	System component	Yes

These are standard system or compiler-provided libraries. They are not distributed with this repository and are automatically available on typical systems.

Usage

After compiling codes, you can run:

./easm examples/hello.asm

Thank you for reading.