libmsx ; C library for MSX

The libmsx library exposes MSX, MSX2, MSX2+, and MSXturboR hardware functionality to the C programmer.

The library is intended for use with the C cross compiler SDCC, and makes it easy to build MSX ROM cartridge image (16KiB, 32KiB, or MegaROM).

MSX is a registered trademark of MSX Licensing Corporation.

Pull requests (PRs) and issues (bug reports, feature requests) are welcome. 😉

libmsx.mp4

LICENSE

Copyright (c) 2021-2025 Daishi Mori (mori0091)

This software is released under the MIT License.
See https://github.com/mori0091/libmsx/blob/main/LICENSE

GitHub libmsx project
https://github.com/mori0091/libmsx

A code snippet (gsinit.s) extracted and derived from the SDCC runtime library are available under the GPLv2 license.
See https://github.com/mori0091/libmsx/blob/main/sdcc/README.md.

API reference

The API reference of the libmsx library is hosted on GitHub Pages.
See https://mori0091.github.io/libmsx/index.html

Supported functionality

The below functionality is supported.

• Getting MSX system version code

• VSYNC based timing synchronization

• Almost of TMS9918A, V9938, V9958 VDP (Video Display Processor) functionality.

  • Display screen mode setting
  • Display area position adjustment
  • Display lines setting (192 lines / 212 lines)
  • VRAM memory map setting (pattern name table, color table, and so on)
  • Color palette
  • Hardware vertical scroll
  • Hardware horizontal scroll
  • Enable / disable display visibility
  • Enable / disable sprites visibility
  • VDP command execution (HMMM, HMMV, LMMM, and LMMV)
  • VRAM read / write
  • … and so on

• GPIO (8-bit parallel I/O port ; a.k.a Joystick I/F)

  • Reading joystick input state.

• Sound output

  • PSG (AY-3-8910)
  • OPLL (YM2413 / MSX-MUSIC)
    • OPLL sound chip inspection, discovery,
    • Enabling/Disabling register access, and
    • Write registers.
  • Konami SCC / SCC+ Sound Cartridge
    • SCC / SCC+ sound cartridge inspection, discovery,
    • Enabling/Disabling register access, and
    • Read/Write registers.

• Sound driver

  • NDP - PSG Driver for MSX
    • NTSC (60Hz)
    • Stop, Start, Pause, Resume, Auto-Repeat.
    • Playing sound effects (SFX) during playing background music (BGM).
    • NDP was originally programmed and provided by naruto2413 and later modified for libmsx by Daishi Mori (mori0091).
    • The original NDP driver for MSX and MML editor/compiler for Windows are distributed at the following site by naruto2413.
      • See also NDP - PSG Driver for MSX
  • LA0 - a PSG, SCC/SCC+, and OPLL sound driver
    • NTSC (60Hz), PAL/SECAM (50Hz), auto detect and auto adjust.
    • Available to specify default playing frequency that the sound data author expecting.
    • Run-time replay speed/frequency control.
    • Stop, Start, Pause, Resume, Auto-Repeat.
    • Playing sound effects (SFX) during playing background music (BGM).
    • VGM files to LA0 file conversion tool is bundled vgm2la.
  • SNDDRV a PSG sound driver
    • SNDDRV covers almost feature of replayer of the Arkos Tracker 2.
    • SNDDRV and libmsx's build system make it easy to integrate Arkos Tracker 2 song file (.aks file) into your application.
    • See also the design note of SNDDRV
  • Another OLD PSG sound driver (sound.h, sound_eg.h) is still available, but is no longer maintained.

• MegaROM Mapper

  • SDCC __banked functions support (SDCC 4.2.0 or later)
  • Supported ROM mappers:
    • ASCII8 ROM mapper
    • ASCII16 ROM mapper

• Utility functions for inspecting MSX slot mechanisms.

  • Various inspection functions; inspect slot contents.
    • MAIN ROM, SUB-ROM, BDOS/FDC,
    • MSX-MUSIC, SCC/SCC+,
    • Internal RAM,
    • ROM cartridges.
  • Iteration function; invoke user-defined callbacks for each slot.

• Compression / Decompression

  • Decompressor of ZX0 data compression format v.2.
    • The ZX0 decompressor for libmsx has been reimplemented by Daishi Mori (mori0091).
    • That supports decompression of ZX0 data in ROM/RAM/MegaROM to RAM/VRAM.
  • The ZX0 file compressor tool. (for PC)
    • The ZX0 file compressor tool reimplemented by Daishi Mori (mori0091) is bundled.
    • ZX0 data compression format v.2 compatible.
    • Supports MSX-optimized ZX0 compression mode to compress MSX BSAVE format files.

The origins of the ZX0 data compression format and algorithm were designed and implemented by Einar Saukas.
See also https://github.com/einar-saukas/ZX0.

Pre-requisites

Target Machine

• MSX
• MSX2
• MSX2+
• MSXturboR

Host Platform

Linux

Host Platform	SDCC version	status
Ubuntu 24.04	4.4.0	✔ (outdated)
	4.5.0	✔ (recommended)

Windows

Host Platform	SDCC version	status
MSYS2 UCRT64	4.4.0	(not tested)
	4.5.0	(not tested)

Ofcourse, Ubuntu on WSL2 is okey. 😄
(WSL2: Windows Subsystem for Linux)

Build tools

• SDCC
  Small Device C Compiler
  http://sdcc.sourceforge.net/

SDCC 4.5.0 or later is recommended.

• Other toolchain required for libmsx
  GNU find, make, gcc, gzip, zcat, xsltproc, and so on.

Install instructions of Build tools

To use libmsx,

1. Install SDCC.
2. Install other toolchain.

Ubuntu

1. Install SDCC

Download a SDCC pre-built binary for Linux from http://sdcc.sourceforge.net/ and install it.

SDCC 4.5.0 or later is recommended.

Don't forget adding SDCC to PATH environment variable.
Add the below to ~/.bashrc or ~/.bash_profile.

At here it is assuming that the SDCC 4.5.0 is installed under ~/sdcc-4.5.0.

export PATH=${PATH}:~/sdcc-4.5.0/bin

Why don't we install sdcc by sudo apt install sdcc ?

Because the latest version of SDCC may not be installed by apt. In case of Ubuntu 24.04, SDCC 4.2.0 is installed. Thus we recommend that you download SDCC 4.5.0 pre-built binary and use it on Ubuntu 24.04 or later.

2. Install other toolchain

sudo apt update
sudo apt install build-essential make gcc gzip xsltproc git

Windows (Ubuntu on WSL2)

The 1st case is using Ubuntu on WSL2 environment.
In this case, it is same as for Ubuntu.

Launch a terminal of Ubuntu on WSL2, and proceed with the above instructions.

Windows (MSYS2)

The 2nd case is using MSYS2 UCRT64 environment.

1. Install SDCC

Download a SDCC pre-built binary for Windows from http://sdcc.sourceforge.net/ and install it.

2. Install other toolchain

Download and install MSYS2.

Then launch a terminal for the MSYS2 UCRT64 environment, and do as follows:

pacman -S coreutils findutils make gcc gzip libxslt git

Don't forget adding SDCC to PATH environment variable.
Add the below to ~/.bashrc or ~/.bash_profile, on MSYS2 UCRT64 environment.

At here it is assuming that the SDCC is installed under C:\Program Files\SDCC.

export PATH=${PATH}:/c/Program\ Files/SDCC/bin

Build instructions of the library and sample projects

The below makes the library libmsx.lib into lib folder, and bundled tools into bin folder.

make

To build sample projects in sample/, do as follows:

make sample

And for cleaning up:

make clean

Build instructions of user applications

There are several sample projects, please refer to the sample/ folder of the libmsx project.

Preparation

Step 1. Make your project's Git repository.

git init my_proj

Step 2. Download libmsx and place it somewhere.

git clone https://github.com/mori0091/libmsx.git libmsx

Step 3. Copy libmsx/mk/Makefile to top of your repository, and customize it.

See https://github.com/mori0091/libmsx/blob/main/mk/Makefile

cp libmsx/mk/Makfile my_proj/

Step 4. Create the folder my_proj/src/ and place your C source files under it or in its subfolders.

mkdir my_proj/src

Build your application

To build your application, do as follows on the top of your repository my_proj.
Then the ROM image will be made into my_proj/bin folder.

make

And for cleaning up:

make clean