Within the ESHO1 final project our group implemented an emulator for the Gameboy Advance.
The current project status includes the following components:
- 2 instruction sets, ARMv4 and Thumb
- 4 DMA channel
- 4 Timer channel
- LCD rendering
- Interrupt processing
- external bios rom support
- (buggy) fallback bios
With this, most games can already be emulated without problems. The following open points remain:
- The 6 audio channels (For 2 of the channels a functional start has already been made in the corresponding branch. However, this is not optimized at all).
- Real Time Clock (RTC) support
For compiling the emulator, SDL2 and gcc are required. If those requirements are met, the provided Makefile can be used for building.
On most distributions SDL2 can be installed via the packet manager, i.e. for Debian:
apt-get install libsdl2-dev
Building:
make
Download SDL2 MinGW version from here.
make
Download SDL2 Visual C++ version from here.
make windows
or to avoid a complete rebuild (after initial make windows)
make windows_
Several flags can be set to enable debug features.
In the src/logging.hpp source file debug output for various submodules can be adjusted.
These are:
| Flag | Debug target / Meaning |
|---|---|
| LEGACY_RENDERING | Use legacy rendering mode (might be more stable, but slower) |
| DEBUG_CLI | Enables interactive debugging tools (see src/debugger.cpp for available commands) |
| DUMP_CPU_STATE | only usable with DEBUG_CLI, dumps the cpu state onto the console after each step, highly recommended to pipe into a file |
| DEBUG_DMA | DMA emulation |
| DEBUG_IRQ | Interrupt emulation |
| DEBUG_TIM | Timer emulation |
| DEBUG_LCD | LCD rendering |
| DEBUG_MEM | Memory management |
| DEBUG_IO | Handling of I/O address space |
| DEBUG_SAVE | Save file handling |
| DEBUG_SWI | Software interrupt emulation |
In src/main.cpp the following additional flags may be adjusted:
| Flag | Meaning |
|---|---|
| LIMIT_FPS | Caps FPS to 60 (considers only time needed for current frame) |
| PRINT_FPS | Prints the current FPS (per frame) onto the console |
| DUMP_ROM | Dumps the dissassembled rom in ARM and Thumb mode onto the console prior to emulation, highly recommended to pipe into a file! |
In src/lcd/defs.hpp
| Flag | Meaning |
|---|---|
| RENDERER_DECOMPOSE_LAYERS | show each layer, useful for graphical debugging |
| RENDERER_DECOMPOSE_BG_COLOR | replaces transparent color with specified one |
| RENDERER_USE_FB_CANVAS | for usage of a frame buffer for showing the image, probably wrong color format in master branch, see rpi branch. This also affects the usage: first argument is expected to be a path to the frame buffer, i.e. /dev/fb1 |
The emulator may be used via the console as follows
./gbaemu rom [bios.rom]
Although the usage of an external bio rom is not required, it is highly recommended as there are known bugs in the fallback solution (i.e. decompression) and no time to fix those (yet).
Save file is automatically generated with appended .sav to the whole rom name: i.e. for rom.gba the resulting save file would be rom.gba.sav.
The keymap is not configurable during runtime, but can be adjusted by modifying the std::map in src/input/keyboard_control.hpp.
| GBA Button | Key mapping |
|---|---|
| A | Space, j |
| B | k, left shift |
| Select | esc |
| Start | enter |
| L | l |
| R | colon, p |
| Up | w |
| Down | s |
| Left | a |
| Right | d |
Specifics on the implementation are to be found in the subdirectory doc.
- For general GBA info: GBATEK
- For Audio: http://belogic.com/gba/
- Further documentation GBADEV
- Demos GBADEV
- Eggvance Blog
- mGBA Blog
- mGBA test suite
- eggvance test suite
The original developers of this project are: