MachineCodeTest

A progressive series of Windows PE executables generated entirely from raw x86 machine code bytes using Python. No compiler, no assembler, no linker — just Python scripts that emit bytes directly into valid PE32 executables.

Programs

Each subdirectory contains a gen_*.py script that generates a working .exe:

| # | Program | Description | Size | |---|---------|-------------|------| | 1 | hello | Hello World — console output via WriteConsoleA | ~2 KB | | 2 | triangle | Pascal's Triangle — loops, arithmetic, formatted output | ~2 KB | | 3 | fib_triangle | Fibonacci Triangle — nested loops, number formatting | ~2 KB | | 4 | gui | GUI Window — Win32 CreateWindowEx, message loop, WndProc | ~4 KB | | 5 | snake | Snake Game — real-time console game with input handling | ~4 KB | | 6 | mandelbrot | Mandelbrot Set — fixed-point math, ASCII art rendering | ~2 KB | | 7 | machedit | Text Editor — PE2-style console editor with file I/O | ~6 KB |

How It Works

Each Python generator script:

1. Builds a PE32 header (DOS stub, COFF header, Optional header, Section table)
2. Constructs an Import Directory Table with kernel32.dll (and user32.dll for GUI) function imports
3. Emits raw x86 machine code bytes using an Asm helper class that supports labels, forward references, and fixups
4. Writes out a valid Windows executable — no external tools required

gen_*.py  →  Asm class (labels, emit, fixups)  →  PE sections (.text, .rdata, .bss)  →  .exe

Quick Start

# Generate and run any program
cd hello
python gen_hello.py
./hello.exe

# Generate the text editor
cd machedit
python gen_machedit.py
./machedit.exe              # empty editor
./machedit.exe file.txt     # edit a file

Requirements: Python 3.6+ and Windows (executables are Win32 PE32)

MachEdit — The Text Editor

The crown jewel: a fully functional PE2-style console text editor generated from ~3400 bytes of hand-crafted x86 machine code.

Features:

• Arrow key navigation, Home/End, PgUp/PgDn
• Character insertion, Backspace, Delete
• Enter (line splitting), line joining
• Vertical scrolling
• File loading from command line
• Save (Ctrl+S)
• Help screen (Ctrl+H)
• Status bar with line/column, modified indicator
• Blue PE2 color scheme
• IME-aware (works on CJK Windows)

Mandelbrot Set

Reference

The reference/ directory contains pe2.asm — an x86 NASM assembly version of the text editor, which served as architectural reference for the machine code implementation.

License

MIT