Date: Mon, 9 Jan 1995 18:59:00 +0500
From: hvb AT netrix DOT com
To: sandmann AT new-orleans DOT neosoft DOT com
Subject: Re: Accessing absolute addresses in memory (>1M) and ports.
Cc: djgpp AT sun DOT soe DOT clarkson DOT edu
Reply-To: hvb AT netrix DOT com

 
> > We have a number of memory mapped devices. Some of them are mapped
> > to the 0xd000 page of the low 1MB, some of them are mapped to the
> > area above 12MB of the physical memory addressing space. Will the call
> > to the DPMI (0x0800) function allow me:
> > 
> >  - to map to the whole 16MB of the physical memory addressing space
> > in one call, so effectively I will be able to obtain an equivalent
> > offset to the 0xe0000000 offset that I have today?
> 
> No.  You can only map the memory which have devices.  It must be 
> outside the range of the DPMI's managed memory, and cannot include
> anything in the 1Mb region.  You will end up with a separate memory
> offset for each device potentially.  I haven't tried this; maybe 
> the providers out there will give the same values each time.  Try it.
> The free DPMI will always return the same values each time.
> 

How do I map to the 0xd000 page of the low 1MB area then?

Thanks,
Hung.