Nintendo - SNES / Famicom (bsnes-mercury Accuracy)¶

Background¶

bsnes-mercury is a fork of higan, aiming to restore some useful features that have been removed, as well as improving performance a bit. Maximum accuracy is still uncompromising; anything that affects accuracy is optional and off by default.

This core has been compiled with the Accuracy profile.

Improvements include:

Improved framerate
Faster ROM loading
HLE emulation of some special chips is optionally restored (defaults to LLE), to improve performance and reduce reliance on those chip ROMs (they're not really easy to find). Chips for which no HLE emulation was developed (ST-0011 and ST-0018) are still LLE.
SuperFX overclock is now available (off by default, of course); if enabled, it makes SuperFX look quite a lot smoother.

The bsnes-mercury cores are not less accurate at default settings than the mainline bsnes cores (you have to explicitly enable 2 core options to switch to the less accurate special chip HLE).

Author/License¶

The bsnes-mercury Accuracy core has been authored by

byuu
Alcaro

The bsnes-mercury Accuracy core is licensed under

GPLv3

A summary of the licenses behind RetroArch and its cores can be found here.

Extensions¶

Content that can be loaded by the bsnes-mercury Accuracy core have the following file extensions:

.sfc
.smc
.bml

Databases¶

RetroArch database(s) that are associated with the bsnes-mercury Accuracy core:

BIOS¶

Required or optional firmware files go in the frontend's system directory.

Filename	Description	md5sum
dsp1.data.rom	DSP1 co-processor firmware	3d81b45fa0c2aa8b852dfb1ece7c0971
dsp1.program.rom	DSP1 co-processor firmware	ae209fbe789fbf11a48aea5ab1197321
dsp1b.data.rom	DSP1B co-processor firmware	1e3f568634a7d8284020dddc0ae905bc
dsp1b.program.rom	DSP1B co-processor firmware	d10f446888e097cbf500f3f663cf4f6d
dsp2.data.rom	DSP2 co-processor firmware	e9417e29223b139c3c4b635a2a3b8744
dsp2.program.rom	DSP2 co-processor firmware	aa6e5922a3ed5ded54f24247c11143c5
dsp3.data.rom	DSP3 co-processor firmware	0a81210c0a940b997dd9843281008ee6
dsp3.program.rom	DSP3 co-processor firmware	d99ca4562818d49cee1f242705bba6f8
dsp4.data.rom	DSP4 co-processor firmware	ee4990879eb68e3cbca239c5bc20303d
dsp4.program.rom	DSP4 co-processor firmware	a151023b948b90ffc23a5b594bb6fef2
cx4.data.rom	CX4 co-processor firmware	037ac4296b6b6a5c47c440188d3c72e3
st010.data.rom	ST010 co-processor firmware	254d70762b6f59f99c27c395aba7d07d
st010.program.rom	ST010 co-processor firmware	1d70019179a59a566a0bb5d3f2845544
st011.data.rom	ST011 co-processor firmware	10bd3f4aa949737ab9836512c35bcc29
st011.program.rom	ST011 co-processor firmware	95222ebf1c0c2990bcf25db43743f032
st018.data.rom	ST018 co-processor firmware	49c898b60d0f15e90d0ba780dd12f366
st018.program.rom	ST018 co-processor firmware	dda40ccd57390c96e49d30a041f9a9e7
sgb.boot.rom	Super Game Boy BIOS

Features¶

Frontend-level settings or features that the bsnes-mercury Accuracy core respects.

Feature	Supported
Restart	✔
Screenshots	✔
Saves	✔
States	✔
Rewind	✔
Netplay	✔
Core Options	✔
RetroAchievements	✔
RetroArch Cheats	✔
Native Cheats	✕
Controls	✔
Remapping	✔
Multi-Mouse	-
Rumble	✕
Sensors	✕
Camera	✕
Location	✕
Subsystem	✔
Softpatching	✔
Disk Control	✕
Username	✕
Language	✕
Crop Overscan	✕
LEDs	✕

Directories¶

The bsnes-mercury Accuracy core's internal core name is 'bsnes-mercury'

The bsnes-mercury Accuracy core saves/loads to/from these directories.

Frontend's Save directory

'content-name'.srm (Cartridge battery save)

Frontend's State directory

'content-name'.state# (State)

Geometry and timing¶

The bsnes-mercury Accuracy core's core provided FPS is 60.0988118623 for NTSC games and 50.0069789082 for PAL games.
The bsnes-mercury Accuracy core's core provided sample rate is 32040.5 Hz
The bsnes-mercury Accuracy core's core provided aspect ratio is dependent on the 'Preferred aspect ratio' core option.

Super GameBoy¶

Warning

Super GameBoy support in this core is Windows only, and has buggy save state support and visual glitches. Use the higan Accuracy core or the nSide Balanced core for simplified, functional, and easily accessible Super Gameboy support.

For Super GameBoy support, you need sgb.boot.rom (in RetroArch's System directory), a GameBoy ROM and a Super GameBoy ROM.

Please note that the Game Boy and Super GameBoy ROMs have to be unzipped.

Super GameBoy is supported via the Subsystem API.

There are two ways to access the Subsystem API.

One way is to access the Subsystem API through RetroArch's GUI like this.

First, we load our GameBoy ROM through 'Load Super GameBoy' in RetroArch's Main Menu.

Next, we load our Super GameBoy ROM through 'Load Super GameBoy' in RetroArch's Menu Menu.

Then, we start the content by selecting 'Start GameBoy' In RetroArch's Menu Menu.

The other way is to launch RetroArch with commandline like this.

retroarch -L {path to bsnes core} {path to Super GameBoy ROM} --subsystem sgb {path to GameBoy rom}

MSU-1¶

Attention

MSU-1 support in this core is complex. Use the Snes9x core for simplified and easily accessible MSU-1 support.

MSU-1 support can be used by loading a correct .bml file.

There's documentation for loading MSU-1 games in standalone higan here.

Core options¶

The bsnes-mercury Accuracy core has the following option(s) that can be tweaked from the core options menu. The default setting is bolded.

Settings with (Restart) means that core has to be closed for the new setting to be applied on next launch.

Allow settings to reduce accuracy [bsnes_violate_accuracy] (disabled|enabled)

Respect accuracy-impacting settings.
Special chip accuracy [bsnes_chip_hle] (LLE|HLE)

**The Allow settings to reduce accuracy core option must be enabled in order for this to function properly. **

Choose whether to use LLE (real BIOS) or HLE (emulated BIOS) for enhancement chips.

HLE is less accurate but also less demanding for the special chips.

The ST-0011 and ST-0018 co-processors cannot be HLE'd.
SuperFX speed [bsnes_superfx_overclock] (100%|150%|200%|300%|400%|500%|1000%)

The Allow settings to reduce accuracy core option must be enabled in order for this to function properly.

Overclock the SuperFX chip. 100% is stock clockspeed.
System region [bsnes_region] (auto|ntsc|pal)

Choose which region the system is from.
Preferred aspect ratio [bsnes_aspect_ratio] (auto|ntsc|pal)

Choose the preferred aspect ratio. RetroArch's aspect ratio must be set to Core provided in the Video settings.
Crop overscan [bsnes_crop_overscan] (disabled|enabled)

Crop out the potentially random glitchy video output that would have been hidden by the bezel around the edge of a standard-definition television screen.
Gamma ramp (requires restart) [bsnes_gamma_ramp] (disabled|enabled)

Simulates the way a console’s display device differs from modern computer monitor’s colour reproduction. In particular, it simulates the slightly-different gamma correction used by the Super Famicom.

Gamma ramp - Disabled

Gamma ramp - Enabled

Controllers¶

The bsnes-mercury Accuracy core supports the following device type(s) in the controls menu, bolded device types are the default for the specified user(s):

User 1 device types¶

None - Doesn't disable input.
SNES Joypad - Joypad
SNES Mouse - Mouse

User 2 device types¶

None - Doesn't disable input.
SNES Joypad - Joypad
SNES Mouse - Mouse
Multitap - Joypad - Allows for up to five players to play together in multitap games.
SuperScope - Lightgun
Justifier - Lightgun
Justifiers - Lightgun - Two Justifiers are plugged in, for two-player Justifier games.

Multitap support¶

Activating multitap support in compatible games can be configured by switching to the Multitap device type for User 2.

Controller tables¶

Joypad¶

User 1 - 5 Remap descriptors	RetroPad Inputs
B
Y
Select
Start
D-Pad Up
D-Pad Down
D-Pad Left
D-Pad Right
A
X
L
R

Mouse¶

RetroMouse Inputs	SNES Mouse
Mouse Cursor	SNES Mouse Cursor
Mouse 1	SNES Mouse Left Button
Mouse 2	SNES Mouse Right Button

Lightgun¶

RetroLightgun Inputs	SuperScope	Justifier(s)
Gun Crosshair	SuperScope Crosshair	Justifier Crosshair
Gun Trigger	SuperScope Trigger	Justifier Trigger
Gun Aux A	SuperScope Cursor
Gun Aux B	SuperScope Turbo
Gun Start	SuperScope Pause	Justifier Start

Compatibility¶

The bsnes-mercury Accuracy core fully emulates all SNES games that have ever been officially released.