README

Advent of Code - Amiga Edition

Cross-platform Advent of Code solver written in Free Pascal with the ability to compile for and run on vintage Commodore Amiga hardware.

Solve puzzles on your PC (x64 Linux/Windows/macOS), test and debug with native tools, then automatically export and cross-compile to Amiga m68k. Same Pascal source code runs on both modern systems and 1980s hardware.

Screenshots

GUI Application

Lazarus IDE

Running on Amiga

Features

• Advent of Code solver written in Free Pascal
• GUI application (Windows, Linux, macOS)
• Cross-compilation to Amiga m68k (68000/68020/68030+)
• Bootable ADF disk image generation
• Docker-based build pipeline
• Configurable CPU targeting

Project Structure

fpc-aoc/
????????? solvers/              # AOC puzzle solutions by year
???   ????????? 2015/
???       ????????? aoc2015day1.pas
???       ????????? aoc2015day2.pas
????????? inputs/               # Puzzle inputs (not included, add your own)
???   ????????? 2015/
???       ????????? day1.txt
????????? templates/            # Templates for Amiga exports
???   ????????? AocInputAmiga.pas
???   ????????? compile-amiga.sh.template
????????? AmigaExport.pas       # Amiga export logic
????????? AocBase.pas           # Core solver framework
????????? AocGui.pas            # GUI application
????????? aoc_solver.lpr        # Main program
????????? Dockerfile.adf-tools  # Docker image for ADF creation
????????? amiga.config          # Amiga build configuration

Requirements

For Modern Development

• Free Pascal Compiler (FPC) 3.2.0+
• Lazarus IDE (optional, for GUI)
• Git

For Amiga Cross-Compilation

• Docker
• The project's Docker images (see Setup section)

For Running on Real Amiga

• Amiga with 68000/68020/68030 CPU
• 8MB+ RAM recommended
• Kickstart 1.3+ (3.0+ recommended)
• WinUAE emulator for testing

Setup

1. Clone the Repository

git clone https://github.com/mbdev87/fpc-aoc.git
cd fpc-aoc

2. Add Your Puzzle Inputs

Create input files for your puzzles:

mkdir -p inputs/2015
# Add your puzzle input from adventofcode.com
echo "your input here" > inputs/2015/day1.txt

3. Build Docker Images (for Amiga cross-compilation)

Build the ADF tools image:

docker build -t adf-tools:latest -f Dockerfile.adf-tools .

Pull the Free Pascal Amiga cross-compiler:

docker pull alb42/crossamigalazarus:latest

4. Configure CPU Target (Optional)

Edit amiga.config to match your Amiga hardware:

# CPU Target Options:
# - 68000: All Amigas (A500, A600, A1000, A2000)
# - 68020: A1200, A3000, A4000, accelerated A500/600
# - 68030: Accelerated Amigas with 68030+
CPU_TARGET=68020

# Optimization Level (1-3)
OPTIMIZATION=2

Usage

Native Solving (Linux/Windows)

Compile and run the solver:

# Linux
lazbuild aoc_solver.lpi
./aoc_solver --year 2015 --day 1

# Windows
lazbuild aoc_solver.lpi
aoc_solver.exe --year 2015 --day 1

GUI Mode

# Linux
./aoc_solver --gui

# Windows
aoc_solver.exe --gui

The GUI allows you to:

• Select year and day
• Run solvers
• Export to Amiga format
• View results

Amiga Cross-Compilation

Method 1: Via GUI

1. Launch GUI: ./aoc_solver --gui
2. Select year and day
3. Click "Export to Amiga"
4. Find generated ADF in amiga/YYYY-dayN-TIMESTAMP/

Method 2: Manual Export

After exporting via GUI, compile for Amiga:

cd amiga/2015-day1-2025-11-27-12-00/
./compile.sh

This will:

1. Cross-compile the Pascal code to m68k
2. Create a bootable ADF disk image
3. Include your puzzle input
4. Add auto-run startup sequence

Method 3: Direct Docker Compilation

docker run --rm \
  -v $(pwd):/sources \
  -w /sources \
  alb42/crossamigalazarus:latest \
  /usr/bin/ppcross68k \
    -Tamiga \
    -Cp68020 \
    -Avasm \
    -XV \
    -Xs \
    -XX \
    -O2 \
    yourprogram.pas

Running on Amiga

WinUAE (Emulator)

1. Open WinUAE
2. Go to Floppy Drives
3. DF0: → Select the generated .adf file
4. Configure:
   • CPU: 68020+ (or 68000 if compiled for it)
   • Chip RAM: 2MB
   • Fast RAM: 8MB minimum
   • Kickstart: 3.0+ recommended
5. Boot the Amiga
6. Program auto-runs on boot

Real Amiga Hardware

1. Transfer ADF to physical floppy using:
   • Greaseweazle
   • Kryoflux
   • Amiga with Gotek drive
2. Boot from the floppy
3. Program auto-executes

Writing Your Own Solvers

Basic Template

unit Aoc2015Day1;

{$mode ObjFPC}{$H+}
{ AmigaUses: Math }  // Optional: add units needed for Amiga

interface

uses
  Classes, SysUtils, AocBase;

type
  TAoc2015Day1 = class(TAocSolver)
  public
    function SolvePart1: String; override;
    function SolvePart2: String; override;
  end;

procedure RegisterSolver;

implementation

{ AmigaExportBegin }
// Optional: Add helper functions here for Amiga export
procedure MyHelper(X: Integer);
begin
  // Helper code
end;
{ AmigaExportEnd }

function TAoc2015Day1.SolvePart1: String;
var
  Line: String;
begin
  for Line in InputLines do
  begin
    // Your solution here
  end;

  Result := IntToStr(answer);
end;

function TAoc2015Day1.SolvePart2: String;
begin
  // Part 2 solution
  Result := IntToStr(answer);
end;

procedure RegisterSolver;
begin
  SolverRegistry.RegisterSolver(2015, 1, TAoc2015Day1);
end;

initialization
  RegisterSolver;

end.

Amiga Export Markers

Use these special comments to control Amiga exports:

Custom Units

{$mode ObjFPC}{$H+}
{ AmigaUses: Math, StrUtils }

Helper Functions

{ AmigaExportBegin }
procedure ParseLine(const S: String; out X, Y: Integer);
begin
  // This function will be included in Amiga export
end;
{ AmigaExportEnd }

How It Works

Cross-Compilation Pipeline

1. Development: Write solvers in Free Pascal on modern system
2. Testing: Run and debug using native compiler
3. Export: GUI generates standalone Amiga program
4. Compilation: Docker runs FPC cross-compiler for m68k
5. ADF Creation: Docker runs xdftool to create bootable disk
6. Deployment: Load ADF in emulator or transfer to real hardware

Technical Details

• Compiler: Free Pascal 3.2.0 with m68k target
• Assembler: VASM (included in crossamigalazarus image)
• ADF Format: 880KB DD floppy, FFS filesystem
• Auto-boot: Startup-sequence in S/ directory
• Input Handling: AocInput.pas provides common patterns

Memory Requirements

Amiga programs compiled with FPC need:

• Minimum: 4MB Fast RAM
• Recommended: 8MB+ Fast RAM
• Chip RAM: 2MB

Without sufficient Fast RAM, programs may crash silently.

Troubleshooting

Docker Image Not Found

# Build ADF tools
docker build -t adf-tools:latest -f Dockerfile.adf-tools .

# Pull Amiga compiler
docker pull alb42/crossamigalazarus:latest

Compilation Errors on Amiga

Check CPU target matches your hardware:

• Error about fpc_mul_longint: Change CPU_TARGET to 68020+
• Program crashes: Increase Fast RAM in WinUAE config
• "Unknown compilerproc": Math unit requires 68020+

ADF Won't Boot

• Ensure ADF has bootblock: xdftool yourfile.adf boot install
• Check startup-sequence is in S/ directory
• Verify FFS format: xdftool yourfile.adf format YourDisk ffs

Contributing

1. Fork the repository
2. Create a feature branch
3. Add your solver in solvers/YYYY/
4. Test on both native and Amiga (if possible)
5. Submit a pull request

Resources

• Advent of Code
• Free Pascal
• FPC Amiga Wiki
• WinUAE
• amitools

License

MIT License - See LICENSE file for details

Acknowledgments

• ALB42 for the crossamigalazarus Docker image
• The Free Pascal team
• The Amiga community
• Eric Wastl for Advent of Code