- Move TIM ISR emulation to dedicated function .tim_emulation and dedicated file timer_isr.s - Make TIM ISR emulation save entirety of ALL_REGTEMPS_BEGIN to ALL_REGTEMPS_END - Improve emulation to allow average TIM rate to be faster compared to vblank rate - Add support for consistent average TIM rate on PAL, for a less system-dependent timer - Add support for different base dividers defined by GB-like TAC_REG variable - Add defines values for "vblank parity mode" to global.s and nes.h - Update crt0 init code to set TMA_REG to vblank parity mode correctly for PAL/Dendy - Update documentation, describing the improved GB TIM emulation and vblank parity mode - Update cross-platform IRQ example to better showcase the emulation
GBDK-2020
GBDK is a cross-platform development kit for sm83, z80 and 6502 based gaming consoles. It includes libraries, toolchain utilities and the SDCC C compiler suite.
Supported Consoles: (see docs)
- Nintendo Game Boy / Game Boy Color
- Analogue Pocket
- Sega Master System & Game Gear
- Mega Duck / Cougar Boy
- NES
Experimental consoles (not yet fully functional)
- MSXDOS
Current Release
Upgrading to a new version? Check the Migration notes. You can find older versions here.
For a full list of changes see the ChangeLog file or online Docs.
Build status
Made with GBDK-2020
See our gallery showcasing Games and Programs made with GBDK, including open source and cart release filters.
Docs
GBDK includes extensive documentation. A good place to begin is the Getting Started Section.
Check the Links and Third-Party Tools Section for a list of recommended emulators, graphics tools, music drivers and more.
For SDCC you can check its website and the manual
Usage
Most users will only need to download and unzip the latest release
Then go to the examples folder and build them (with compile.bat on Windows or running make). They are a good starting point.
The sources in this repo are only needed if you want to re-compile GBDK-2020 yourself instead of using the release binaries linked above.
Discord servers
-
gbdk/zgb Discord - For help with using GBDK (and ZGB), discussion and development of gbdk-2020
-
gbdev Discord - There is a #gbdk channel and also people with a lot of Game Boy development knowledge
-
SMS Power! Discord - Additional SMS & Game Gear discussion and resources.
Forums
- The Game Boy Development Forum - A good place to search for Game Boy related answers.
- SMS Power! Forum - Additional SMS & Game Gear discussion and resources.
Current status
- Updated CRT and library that suits better for game development
- SDCC Versions
- A custom build of SDCC is used with patches to support Sega GG/SMS and the Nintendo NES. See the github workflow for details of how to patch and build SDCC.
- The default calling convention changed in
SDCC 4.2. This is supported starting withGBDK-2020 4.1.0. Older versions of GBDK should use SDCC builds #12539 or older (see per-version GBDK notes).
- The compiler driver lcc supports the latest sdcc toolchain.
Origin
Over the years people have been complaining about all the GBDK issues caused by a very old version of SDCC (the compiler). This is a proper attempt of updating it while also keeping all the old functionality working, like support for banked code and data and so on.
The last version in the OLD repo is 2.96 although releases are available until 2.95-3. Version 2.96 is the starting point of this repo.
Build instructions
Unless you are interested on recompiling the sources for some reason (like fixing some bugs) you don't need to build GBDK
- Windows only: Download and install mingw
- Clone, download this repo or just get the source from the releases
- Download and install the PATCHED sdcc builds from the separate repo for that (https://github.com/gbdk-2020/gbdk-2020-sdcc).
- On Linux don't use package managers The latest release available won't work, you need to compile or download one of the nightlies
- Create SDCCDIR environment variable, that points into the folder, where you installed sdcc
- Open command prompt or a terminal, go to the root directory of the repo and run make
