Meteor GBA - RetroBIOS¶
| Type | libretro |
| Source | https://github.com/libretro/meteor-libretro |
| Version | v1.4 |
| Profiled | 2026-03-18 |
| Cores | meteor |
| Systems | nintendo-gba |
No BIOS or firmware files required. This core is self-contained.
Meteor is a Game Boy Advance emulator by Philippe Daouadi (2009-2011).
The libretro port does NOT load or use any external BIOS file. The core has a complete HLE BIOS implementation (ameteor/source/bios.cpp) that handles GBA SWI calls directly in C++. When no real BIOS is loaded (HasBios() returns false), Cpu::SoftwareInterrupt() dispatches SWI calls to the HLE handlers instead of executing the BIOS ROM (ameteor/source/cpu.cpp:244-311).
The standalone frontends (GTK, text) expose LoadBios() for optional real BIOS loading, but the libretro port (libretro/libretro.cpp) never calls LoadBios() and never queries RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY. The retro_load_game() function only loads the ROM via LoadRom().
HLE SWI coverage: SoftReset (0x00), RegisterRamReset (0x01), Halt (0x02), IntrWait (0x04), VBlankIntrWait (0x05), Div (0x06), DivArm (0x07), Sqrt (0x08), ArcTan (0x09), ArcTan2 (0x0A), CpuSet (0x0B), CpuFastSet (0x0C), BgAffineSet (0x0E), ObjAffineSet (0x0F), LZ77UnCompWram (0x11), LZ77UnCompVram (0x12), HuffUnComp (0x13), RLUnCompWram (0x14), RLUnCompVram (0x15).
Missing from HLE: Stop (0x03), BitUnPack (0x10), Diff8bitUnFilter (0x16-0x17), Diff16bitUnFilter (0x18), SoundBias (0x19), SoundDriverInit (0x1A-0x1F), MidiKey2Freq (0x1F), SoundDriverVSyncOff/On (0x28-0x29), GetBiosChecksum (0x0D).
The BIOS memory region (0x00000000-0x00003FFF, 16 KB) is allocated only if LoadBios() is called. Memory reads to this region return BIOS protection values (0x0E for 8-bit, 0xF00E for 16-bit, 0xE1B0F00E for 32-bit) when no BIOS is loaded and PC is outside the BIOS area.
Bios000h() (entry point) initializes stack pointers and jumps to 0x08000004, matching real GBA hardware boot sequence. In the libretro port, retro_reset() resets all units except BIOS and ROM memory.
Generated on 2026-03-20T19:12:20Z