Nuance - RetroBIOS¶
Technical notes
NUON emulator written by Mike Perry (2002-2007) and continued as NuanceResurrection by Carsten Waechter from the source archive released after the author's death. The Linux and libretro ports were merged into the upstream tree in 2026 (pull request 75), so the port and the upstream share the same revision.
The three BIOS files are not firmware dumps. bios.cof, minibios.cof and minibiosX.cof are Aries assembly implementations of BIOS routines, assembled from bios.s, minibios.s and minibiosX.s in the source tree; every other BIOS call is handled in C++ through BiosJumpTable (src/bios.cpp:395-547). The entries left to the assembly code are the comm bus calls, TimeToSleep, MPEWait and BiosGetInfo.
retro_load_game looks for
Two builds of bios.cof exist. The source tree carries the NuanceExperimental build (23938 bytes, 12 sections, with commrecv_vars and commrecv_queues); the 0.6.6 and 0.6.7 release archives ship the 2007 build (19410 bytes, 10 sections). Both carry the same biosvars, haltab, biosinfo, halstub, biosdata, halts and controllerdata sections and the C++ side references neither extra section.
nuance.cfg is read from the working directory, then from the directory of the running executable (src/NuonEnvironment.cpp:533-549); without it the values set in NuonEnvironment::Init apply. The GLSL shaders are opened from the working directory and fall back to the copies compiled into the binary (src/ShaderProgram.cpp:85-135, src/embedded_shaders.h). FlashEEPROM.bin is read by the FlashEEPROM constructor and written by the destructor, both relative to the process working directory at load and unload of the core (src/FlashEEPROM.h:36-51). Game data (nuon.run, nuon.dat) is read from the loaded disc image or directory; no other fixed file is opened.
9 files | 3 required, 6 optional | 8 in repo, 1 missing
bios.cof required in repo bundled
BIOS routines for MPE3, Aries COFF assembled from bios.s
- Path:
nuance/bios.cof - Size: 23.4 KB
- SHA1:
515a3d9a9e43... - MD5:
23bf80c259f1... - Source:
src/libretro.cpp:313-352,src/NuonEnvironment.cpp:581,src/NuonEnvironment.cpp:603-605,src/bios.cpp:566-582,src/coff.cpp:47-70 - Loaded into MPE3 by InitBios. The 2007 build shipped in the release archives (19410 bytes, sha1 4f42ed8f5e171cc79112d1c1e201381e83b1fc0d) loads the same way.
minibios.cof required in repo bundled
Media MPE minibios for MPE0, assembled from minibios.s
- Path:
nuance/minibios.cof - Size: 7.7 KB
- SHA1:
5265dbc871ad... - MD5:
1abc7f6265b8... - Source:
src/media.cpp:243-321,src/bios.cpp:661,src/Bios.h:29-33 - Loaded by MediaInitMPE when the media MPE is MPE0, which InitBios does at every BIOS initialisation. Entry point and interrupt vectors come from the fixed addresses in Bios.h.
minibiosX.cof required in repo bundled
Media MPE minibios for MPEs 1 to 3, addresses shifted down by 4 KB
- Path:
nuance/minibiosX.cof - Size: 7.7 KB
- SHA1:
e45a96ce1848... - MD5:
ceb37f4e78c1... - Source:
src/media.cpp:277-296,src/Bios.h:35-38 - Loaded by MediaInitMPE when a program installs the minibios on an MPE other than MPE0.
nuance.cfg optional in repo bundled
Emulator configuration (compiler options, audio interrupts, controller mappings)
- Path:
nuance/nuance.cfg - Size: 3.3 KB
- SHA1:
dfbac2a22f17... - MD5:
20becfdb9320... - Source:
src/NuonEnvironment.cpp:533-549,src/NuonEnvironment.cpp:917-1056 - Read from the working directory, then beside the running executable. Absent file leaves the defaults of NuonEnvironment::Init in place.
video_generic.vs optional in repo bundled built-in fallback
GLSL vertex shader
- Path:
nuance/video_generic.vs - Size: 491 B
- SHA1:
92fca43b9229... - MD5:
5944fea1ff20... - Source:
src/video.cpp:119,src/ShaderProgram.cpp:85-135,src/embedded_shaders.h:31-52 - Opened from the working directory; the copy compiled into the binary is used when the file is absent. The release archives ship the file without the EMBED_HLSL guards (413 bytes).
video_m32_o32.fs optional in repo bundled built-in fallback
GLSL fragment shader, YCrCb to RGB conversion
- Path:
nuance/video_m32_o32.fs - Size: 6.0 KB
- SHA1:
d0477bd73ba5... - MD5:
e23f4668fea6... - Source:
src/video.cpp:120,src/ShaderProgram.cpp:85-135,src/embedded_shaders.h:31-52 - Selected when UseCRTshader is disabled in nuance.cfg. Same lookup and fallback as video_generic.vs; the release copy is 6090 bytes.
video_m32_o32_crt.fs optional in repo bundled built-in fallback
GLSL fragment shader with CRT post-processing
- Path:
nuance/video_m32_o32_crt.fs - Size: 7.9 KB
- SHA1:
e57671f844c3... - MD5:
2e1335cd9b14... - Source:
src/video.cpp:120,src/ShaderProgram.cpp:85-135,src/embedded_shaders.h:31-52 - Selected when UseCRTshader is enabled, the shipped default. Same lookup and fallback as video_generic.vs; the release copy is 8052 bytes.
FlashEEPROM.bin optional in repo bundled
Atmel AT49BV162A flash ROM image, 2 MB at 0xF0000000
- Size: 2.0 MB
- Source:
src/FlashEEPROM.h:36-51,src/FlashEEPROM.cpp:273-292,src/dma.cpp:679-693 - Read by the FlashEEPROM constructor from the process working directory when the core is loaded, truncated to 2 MB, and written back by the destructor. The release archives ship one; its content is the flash state of the session that produced it.
breakpoint.txt optional missing standalone
Single breakpoint address, first line in hexadecimal
- Source:
src/NuanceMain_linux.cpp:124,src/NuanceMain.cpp:446 - Read from the working directory by the standalone executables only; NuanceMain.cpp and NuanceMain_linux.cpp are excluded from the libretro build (CMakeLists.txt:190).
Generated on 2026-09-14T09:03:10Z