🚀 go-pugleaf

     -=> Sl8nl@cc.usu.edu spoke of "Re: modey vs 13h" <=-
    To All at 08-10-92  03:10
 Sl> I see a potential problem there in that I have a VGA shareware
 Sl> manual... and the complete description of the register set is around
 Sl> 550k!!! (And that doesn't include the 4 chapters the guy left out so
 Sl> the file would be downloadable!)

Well a DETAILED description combined with terse programing
examples.  The registers that are pertinent to graphics/game
programers.

 Sl> I still prefer the Blitter Chip...

Don't we all!  :)

 Sl> Then again...I just saw the Cronolog demo.  Blew my socks off.  As
 Sl> many of you know, I have written an interrupt-driven Amiga module
 Sl> player on the IBM; it pumps out one byte each interrupt call.  This

Thatwould be REAL slow!

 Sl> resulted in SLOOOOWWWWW system access.  In fact, since IRQ 08 is a

Never mind :)z

 Sl> priority interrupt, the system slowed  down to 1/4 "impulse" (sometimes
 Sl> less, depending on the module).  Next, I just finished writing a DMA
 Sl> based module player...for any sound card  capable of digitized output
 Sl> through the DMA.  That opened up plenty of system, enough now to be
 Sl> bearable in programming.

You must have a SB with DMA.  after reading that intresting post
on DMA abuse.  I'm tempted to write a BGI driver that takes
advantage of the memory to memory DMA exfer for the GET and PUT
images.  On my machine that would be 800k per second or 800000
pixels per second in mode 13h not bad!

 Sl> OK, my point is, at least as far as I can tell, the Cronolog demo
 Sl> played it the byte way, not through the DMA.  I figured no way.  But
 Sl> it's true!  They can play through the Covox, the Soundblaster, the
 Sl> internal speaker, a DAC.  The Soundblaster is the only one that can use
 Sl> DMA out of the above, but it doesn't appear that they do.  I can see
 Sl> pulling the graphics off at such high speeds, but graphics and sound?

My guess is they used polling combined with interupts.  Also if
you can get the systtem to do other things while your pumping the
printer port then your in good shape.  I wish they had made the
hardware so that you could just set up a DMA channel and program
the channels speed for a given port :)

        Stephen Cyberman@Toz.Buffalo.NY.US
        Scripted at Tue  08-11-1992  09:30:26

... Morality is timeless,......
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