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# bsnes-mercury - RetroBIOS

Type | libretro
Classification | enhanced_fork
Source | https://github.com/libretro/bsnes-mercury
Upstream | https://byuu.org/higan
Version | v094 (Mercury)
Profiled | 2026-03-25
Cores | bsnes_mercury_accuracy, bsnes_mercury_balanced, bsnes_mercury_performance
Systems | nintendo-snes, nintendo-sgb, nintendo-satellaview, nintendo-sufami-turbo

Technical notes

Fork of higan v094 by Alcaro. Restores HLE for coprocessor chips removed in v094, adds firmware_appended support and SuperFX overclocking. Three profiles: accuracy, balanced, performance (PPU differs, not firmware). Core option bsnes_chip_hle (default LLE, requires bsnes_violate_accuracy) controls HLE/LLE at runtime. ref: target-libretro/libretro.cpp:428-442

Firmware loaded from system_dir via file::exists + mmapstream. No hash or size validation on any firmware file. ref: target-libretro/libretro.cpp:242-264

firmware_appended: firmware can be appended to end of ROM file. ref: ananke/heuristics/super-famicom.hpp:83

SPC700 IPL ROM (64 bytes) is embedded in the binary. ref: target-libretro/libretro.cpp:39

Upstream higan v094 by byuu (2014, site defunct). Mercury preserves v094 code with HLE additions documented in changes.diff at repo root.

18 files | 0 required, 18 optional | 18 in repo, 0 missing | 13 with HLE fallback

`dsp1.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 6.0 KB
- Source: `sfc/cartridge/markup.cpp:422-432`
- Platforms: lakka, retroarch, retropie
- only loaded via custom BML manifest, ananke uses dsp1b

`dsp1.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 2.0 KB
- Source: `sfc/cartridge/markup.cpp:422-432`
- Platforms: lakka, retroarch, retrodeck, retropie
- only loaded via custom BML manifest, ananke uses dsp1b

`dsp1b.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 6.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:381`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp1b.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 2.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:382`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp2.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 6.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:403`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp2.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 2.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:404`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp3.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 6.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:417`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp3.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 2.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:418`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp4.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 6.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:431`
- Platforms: lakka, retroarch, retrodeck, retropie

`dsp4.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 2.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:432`
- Platforms: lakka, retroarch, retrodeck, retropie

`cx4.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 3.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:146`
- Platforms: lakka, retroarch, retrodeck, retropie

`st010.program.rom` -optional, HLE available

- System: nintendo-snes
- Size: 48.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:445`
- Platforms: lakka, retroarch, retrodeck, retropie

`st010.data.rom` -optional, HLE available

- System: nintendo-snes
- Size: 4.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:446`
- Platforms: lakka, retroarch, retrodeck, retropie

`st011.program.rom` -optional

- System: nintendo-snes
- Size: 48.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:460`
- Platforms: lakka, retroarch, retrodeck, retropie

`st011.data.rom` -optional

- System: nintendo-snes
- Size: 4.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:461`
- Platforms: lakka, retroarch, retrodeck, retropie

`st018.program.rom` -optional

- System: nintendo-snes
- Size: 128.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:475`
- Platforms: lakka, retroarch, retrodeck, retropie

`st018.data.rom` -optional

- System: nintendo-snes
- Size: 32.0 KB
- Source: `ananke/heuristics/super-famicom.hpp:476`
- Platforms: lakka, retroarch, retropie

`sgb.boot.rom` -optional

- System: nintendo-sgb
- Size: 256 B
- Source: `ananke/heuristics/super-famicom.hpp:133`
- Platforms: lakka, retroarch, retropie

Generated on 2026-03-25T14:56:43Z