From: "Carlos Giani_AEN2003 (M2003)" <DARKVALE AT pcc DOT tgm DOT ac DOT at>
Organization:  TGM / PCC
To: djgpp AT delorie DOT com
Date:          Thu, 25 Feb 1999 11:51:30 MET-1MDT
Subject:       Re: HELP! NEED VERY SIMPLE TUTOR OF DMA PROGRAMMING!
X-mailer: Pegasus Mail v3.22
Message-ID: <14E13120AE0@pcc.tgm.ac.at>
Reply-To: djgpp AT delorie DOT com

> Hi!
> 
> I need a simple and easy tutorial on DMA-programming for Soundblaster.
> 
> Fozzie
> 
> 

Ahem... DMA programming in Protected Mode... that's painfully...
Well, I'm finishing a SoundBlaster multichannel sound system for 
DJGPP, you can rip the DMA stuff from there...

Anyway, here is a tip for you:
Allocate some DOS memory for DMA transfer. The DMA chip doesn't know 
anything about DPMI mem or virtual memory, so DOS mem is the best and 
easiest way. Next, the DOS memory block shouldn't be greater than 64k.
VERY IMPORTANT: The memory block MUST NOT be between two DMA pages.

       DOS segment & offset:     4000:34CF
       Linear address:           434CF
       DMA page & offset:        4:34CF
       
A good solution is to allocate a memory block which is two times 
bigger than needed.

         

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| Carlos Giani_AEN2003, PC-Club (M2003)               |
| TGM - Schule der Technik, Abteilung Elektronik      |
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