#23 Gravis Ultrasound support

I'm thinking a bit of GUS emulation would be a useful
addition to DOSbox. Not only would it allow you to run
old GUS-only 64K intros (though I admit, most of them
need DPMI support) - in most games it'd be more
efficient than the Soundblaster driver, because all the
mixing would be done outside the emulator (possibly
even in the hardware) rather than inside on the virtual
CPU.

I might be prepared to try implementing it, too. IIRC
the official GUS specs were eventually released for
free by Gravis, so it shouldn't be impossible to code
an accurate emulator.

[Guillaume Serre]

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I just started to code a gus emulator for dosbox. Right now
most programs detect a gus and the dram is completely
emulated with registers or dma access. but still no sound
... I'm still working on it but I would like help so tell me
if you're interested.

[Qbix]

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Any interresting updates on this matter ?

[Tibor Schütz]

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Adding GUS emulation to DOSbox would be great for running
several hard-to-run demos and intros, however do not expect
much benefit for games and trackers.

Speed wise, GUS support will be a bit faster since the mixing is
done by native code rather than by interpreted x86 code -
assuming that GUS mixing is used!

However, it is very unlikely that hardware acceleration will be
of any use: Quite a lot of playback routines require exact
emulation of the GUS, thus translating the GUS registers to the
hardware voices would be tricky. Even worse, quite a lot of
those routines update or read the GUS registers several
thousand times per second - thus, the overhead for translating
would be much greater than the minimal speed benefit gained.

Concerning games, most treat the GUS just like any other
soundcard: As a combination of a MIDI and single stream
playback device. There, using GUS in combination with SBOS,
Ultramid or MegaEM wouldnt be a better alternative for SB
and MIDI, but might cause additional problems due to the TSRs
involved.

Only the few ones supporting the wavetable directly would
benefit much of it.

[Dean Beeler]

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Just added full GUS functionality to the CVS. Enjoy.