Date: Tue, 14 Jan 97 11:26:22 GMT
Message-Id: <9701141126.AA12985@leopard.proteon.com>
From: Neil Jarvis <Neil DOT Jarvis AT proteon DOT com>
To: hotpulp AT netidea DOT com, salvador AT natacha DOT inti DOT edu DOT ar
Cc: djgpp AT delorie DOT com
Subject: Re: DMA buffer in protected mode
Reply-To: Neil DOT Jarvis AT proteon DOT com
Mime-Version: 1.0 (generated by tm-edit 7.43)
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Hi Shawn and SET,

>> In protected mode, to make a DMA buffer, one must allocate memory under
>> 1M, correct? 
>
>Yes.

No. It depends for what device we are talking about. For example I
have program the DMA for an ISA device that can address any memory
up to 16M.

The trick about using memory above 1M is getting the physical address
to program the DMA with. If you are interested I have a piece of code
that lets me malloc() the DMA buffer and then work out its the
physical address.

-Neil

-- 
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                              Neil Jarvis
    Proteon International Ltd, R&D, York, UK. Tel: (+44) 1904 693409
                        Neil DOT Jarvis AT proteon DOT com
                   http://tom.proteon.com:8080/~naj/
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                          Thought of the day:
               The gene pool could use a little chlorine.
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