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Index > DOS > Example of port I/O virtualisation

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bjt



Joined: 24 Jun 2013
Posts: 2
bjt
Hi all,

I put together a TSR to emulate a MPU-401 MIDI interface card. Release with source: http://bjt42.github.io/softmpu

Things that might be interesting from a code perspective:

Calls high-level C procs from asm
I/O port trapping using EMM386
Hooking EMM386 GDT to allow PM access to far data
H/W interrupt generation using RTC
H/W interrupt generation using Sound Blaster
Delay timing using port 061h

Source has comments. Some of this stuff is not at all well documented so may come in useful for someone.


Last edited by bjt on 26 Jun 2013, 14:20; edited 2 times in total
Post 24 Jun 2013, 11:57
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nop



Joined: 01 Sep 2008
Posts: 165
Location: right here left there
nop
good work bjt but ur site say Microsoft C 6.0A & MASM 6.11 are required Shocked
Post 24 Jun 2013, 22:40
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nop



Joined: 01 Sep 2008
Posts: 165
Location: right here left there
nop
btw welcome to fasm board bjt Wink
Post 24 Jun 2013, 22:42
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bjt



Joined: 24 Jun 2013
Posts: 2
bjt
Yes not FASM I am afraid. Still I think the code may come in handy for someone Smile
Post 25 Jun 2013, 11:44
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rugxulo



Joined: 09 Aug 2005
Posts: 2341
Location: Usono (aka, USA)
rugxulo
When I saw this, I vaguely remembered such things would require MS EMM386 or similar.

BTW, I assume OpenWatcom + JWasm could be easily used to rebuild this, but I've not looked closely nor actually tried.

But it's still very impressive, though. Kudos. Cool
Post 04 Jul 2013, 19:01
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