whatisgithub

What is riscboy?

wren6991/riscboy — explained in plain English

Analysis updated 2026-05-18

500CAudience · researcherComplexity · 5/5Setup · hard

In one sentence

RISCBoy is an open-source portable game console built from scratch, including a custom RISC-V processor, graphics hardware, and PCB design.

Mindmap

mindmap
  root((RISCBoy))
    What it does
      Custom RISC-V processor
      Graphics pipeline
      PCB hardware design
    Tech stack
      Verilog
      RISC-V RV32IMC
      KiCad
      FPGA toolchains
    Use cases
      FPGA synthesis and testing
      PCB manufacturing
      Processor verification study
    Components
      Hazard5 CPU core
      Busfabric
      Memory controllers

Code map

Detail Auto

An interactive map of this repo's files and how they connect — its source is parsed live in your browser. Click Visualize to build it.

filefunction / class

What do people build with it?

USE CASE 1

Study or extend a complete custom RISC-V processor and graphics pipeline built in Verilog.

USE CASE 2

Synthesize and run the RISCBoy gateware on an iCE40 or ECP5 FPGA development board.

USE CASE 3

Manufacture the RISCBoy PCB design through a low-cost prototyping service to build real hardware.

What is it built with?

VerilogRISC-VCKiCadFPGA

How does it compare?

wren6991/riscboyv4bel/januscape0xdeadbeefnetwork/ssh-keysign-pwn
Stars500507514
LanguageCCC
Setup difficultyhardhardmoderate
Complexity5/55/54/5
Audienceresearcherresearcherresearcher

Figures from each repo's GitHub metadata at analysis time.

How do you get it running?

Difficulty · hard Time to first run · 1day+

Requires building a RISC-V toolchain and open-source FPGA synthesis tools from source.

License terms were not covered in the provided explanation.

So what is it?

RISCBoy is an open-source portable game console built entirely from scratch, including its own custom processor, graphics hardware, and printed circuit board design. The creator describes it as a version of a Game Boy Advance imagined for a world where the RISC-V processor design existed decades earlier, built as a personal tribute to the handheld consoles of their childhood. At the heart of the project is a custom processor compatible with the RISC-V RV32IMC instruction set, along with a graphics pipeline for drawing images to a screen, and supporting hardware such as memory controllers and basic input and output connections. All of this hardware is described in Verilog, a language used to design digital circuits, and is built to fit onto a specific budget FPGA chip, a type of reconfigurable hardware, with a fairly limited amount of logic capacity. The processor has been checked against official RISC-V compliance tests and additional verification tools to confirm it behaves correctly. Building and testing RISCBoy is a multi-step hardware development process rather than a simple software install. It requires cloning the repository along with its linked sub-projects, building a specialized compiler toolchain for the RISC-V instruction set, and using open-source chip design tools to turn the Verilog design into a file that can be loaded onto an FPGA board. The README also documents the printed circuit board design, including a real revision of the board that can be manufactured through a low-cost prototyping service, and it notes that a redesigned version is planned once the underlying processor and startup software are more mature. This project is aimed at people with a background in digital hardware design or embedded systems who want to explore or extend a complete, working custom computer built from first principles, not those looking for a plug-and-play emulator or ready-to-play device.

Copy-paste prompts

Prompt 1
Walk me through cloning RISCBoy with submodules and building the RV32IMC toolchain it needs.
Prompt 2
Explain how RISCBoy's custom RISC-V processor differs from using an off-the-shelf CPU core.
Prompt 3
How do I synthesize the RISCBoy gateware for an iCE40 HX8k FPGA using the open-source toolchain?
Prompt 4
Summarize the directory structure of this repo and what each part of the hardware design covers.

Frequently asked questions

What is riscboy?

RISCBoy is an open-source portable game console built from scratch, including a custom RISC-V processor, graphics hardware, and PCB design.

What language is riscboy written in?

Mainly C. The stack also includes Verilog, RISC-V, C.

What license does riscboy use?

License terms were not covered in the provided explanation.

How hard is riscboy to set up?

Setup difficulty is rated hard, with roughly 1day+ to a first successful run.

Who is riscboy for?

Mainly researcher.

Open on GitHub → Ask about another repo

This repo across BitVibe Labs

Verify against the repo before relying on details.