Date: Tue, 14 Sep 93 13:12:57 -0400
From: DJ Delorie <dj AT ctron DOT com>
To: sandmann AT clio DOT rice DOT edu
Cc: rgrimes AT gndrsh DOT cdrom DOT com, djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Accessing real memory (ie, below 1MB) under go32


> 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.

As of 1.11 this area is available in all modes.

> 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?)

Correct.

> 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?

1.11's DPMIsim makes that kind of change to go32.exe obsolete.  I have
yet to work in extension mechanisms for int86() though.