From:	pete AT duchess DOT compulink DOT co DOT uk
Newsgroups:	comp.os.msdos.djgpp
Subject:	BEGINNER - DJGPP array addresses!!! HELP
Date:	Thu, 02 Oct 1997 22:47:57 GMT
Message-ID:	<875803348.236.0.nnrp-08.9e9889d0@news.demon.co.uk>
NNTP-Posting-Host:	mythinc.demon.co.uk
Lines:	31
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

I am working on the BT848 chip and with the sample code comes the
DJGPP compiler etc.

There are various routines to talk to the PCI-based chip and one
requires sending the address of mode 13 graphics. The routine simply
says:

risc_main[i*2+1]=bt848.GetScreenPhysAdr() + i * width * 2;

No problems, anoth routine SetScreenPhyAdr accepts 0xa0000 which we
all know is the base address for mode 113h graphics. No other info is
passed, so as a Borland small model programmer I figured this is a
simple 32-bit address. BUT I wanted the card to write to memory
instead of Video memory, so I created an array

char m[80000]; 

which is WAY oversize. Then I altered the code to read:

risc_main[i*2+1]=(unsigned int) &m + i * width * 2;
And all manner of variations, but the program when running just goes
away for a walk. Obviously I'm missing something, all I want to do is
pass the address of the local array to the routine. (I want to work on
the graphics instead of simply displaying them).

Comments please, and be delicate, never done 32 bit flat programming,
Always used Borland small model.

Regards, pete AT duchess DOT cix DOT co DOT uk

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