From:	sandmann AT clio DOT rice DOT edu (Charles W. Sandmann)
Subject:	Re: Accessing real memory (ie, below 1MB) under go32
To:	rgrimes AT gndrsh DOT cdrom DOT com (Rodney W. Grimes)
Date:	Tue, 14 Sep 1993 10:14:34 -0600 (CDT)
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu (DJGPP Mailing List), dj AT ctron DOT com (DJ Delorie)

> The dosmem.s file allows you to read and write memory below 1M.  What
> they don't provide is a mechanism for allocating and freeing memory
> below 1M.  These functions are currently useful for accessing the BIOS
> data area or at-bus peripherals.

There is a 4K buffer in low memory (___transfer_buffer contains the 
32 bit address in .s gas code).  This value is currently only set for non-DPMI
mode (and is NULL for DPMI).  This area can be used if you understand the
GO32 extender calls which use it and don't interfere with them.

If you are willing to do DPMI only, you can call the Int 31h call to allocate
low memory under DPMI.  This is probably better, since I believe V1.11
emulates this DPMI function for non-DPMI, so you would have future
compatibility built in (is this correct DJ?)

Finally, I know that for one commercial software project that has
been recently done with DJGPP they needed to add Int 13 support to the
extender.  Maybe it's time to put that in the release?

I missed part of the discussion, our mail area has been full for the last
week so I didn't get any mailing list items :-(

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