RetroC64 1.0.2

RetroC64

<img align="right" width="160px" height="160px" src="https://raw.githubusercontent.com/RetroC64/RetroC64/main/img/RetroC64.png">

The RetroC64 SDK brings genuine Commodore 64 development directly into your C# and .NET workflow. Build, assemble, and run real 6510 programs without leaving your IDE - no external toolchain required!

✨ Features

• 🚀 Zero-friction dev loop - Emit PRG/D64 and auto-launch live coding into VICE straight from .NET.
• 🧱 Fluent 6510 assembler with Asm6502 - Labels, sections, data blocks, helpers, and source mapping back to C#.
• 🧪 BASIC integration - Ideal for quick demos and prototyping.
• ⚙️ Core helpers - C64Assembler with Zero-Page allocator, raster IRQ setup, memory, and CPU/NMI utilities from RetroC64.Core assembly.
• 🎨 Sprite pipeline with SkiaSharp - Draw in Skia and convert to C64 sprite bytes automatically.
• 🎵 SID tooling - Loader, relocator, and player (target address and ZP ranges).
• 💾 Disk and program formats - D64 and PRG support.
• 🔌 Cross-platform - Targets net9.0+.
• 🐞 First-class VS Code debugging
  • Attach to debugger: Connect to RetroC64 debugger running on port 6503 (default)
  • Register access: Full read-write access to CPU registers, CPU flags, stack, and zero page addresses
  • Hardware registers: Access to VIC and SID registers
  • Breakpoints: Set code breakpoints and data breakpoints (watchpoints)
  • Execution control: Step-in, step-over, step-out, pause, and continue
  • Memory inspection: View RAM contents
  • Code analysis: View disassembly

📦 Install

Make sure you have the .NET SDK 9.0 or higher installed.

Then, you simply need to add the RetroC64 to your .NET project:

dotnet add package RetroC64

🚀 Quick Start

Create this simple Program.cs:

using Asm6502;
using RetroC64;
using RetroC64.App;
using static RetroC64.C64Registers;

// A program is a command line app that builds and runs a 6510 assembly program.
return await C64AppBuilder.Run<HelloAsm>(args);

/// <summary>
/// A simple assembler program that changes the background and border colors.
/// </summary>
public class HelloAsm : C64AppAsmProgram
{
    protected override Mos6502Label Build(C64AppBuildContext context, C64Assembler asm)
    {
        asm.Label(out var start)
            .BeginCodeSection("Main")
            .LDA_Imm(COLOR_RED)
            .STA(VIC2_BG_COLOR0)
            .LDA_Imm(COLOR_GREEN)
            .STA(VIC2_BORDER_COLOR)
            .InfiniteLoop()
            .EndCodeSection();
        return start;
    }
}

Run: dotnet watch -- run with launch VICE and allow live coding. It will display the following screen:

See the emulator setup section in the user guide.

🧪 Examples

Go to the Examples repository for more examples.

📖 User Guide

For more details on how to use RetroC64, please visit the user guide.

🪪 License

This software is released under the BSD-2-Clause license.

🤗 Author

Alexandre Mutel aka xoofx.