Date: Tue, 25 Feb 1997 11:36:24 +0100 (MET)
From: Christoph Kukulies <kuku AT gil DOT physik DOT rwth-aachen DOT de>
Message-Id: <199702251036.LAA06425@gil.physik.rwth-aachen.de>
To: djgpp AT delorie DOT com
Subject: far pointer - passing to realmode

Envirnoment: djgpp V201, cwsdpmi


I'm trying to communicate with a TSR (stepper motor driver).
The vendor supplies a INT 0x78 interface and using __dpmi_int()
works fine so far. I could test some basic functions.

Now comes the following difficulty:

My program is in protected mode - flat linear addressing. The driver
requires for some functions an address to be passed (as far pointer,
seg,offset) where the driver can find a parameter list (of 12 to 16,
maybe max 32 bytes).

How can I supply these parameters from an address (linear) in my 
program and convert it into a seg:offset to be used by the
realmode program? Would that work at all or would it be better to
use some low memory area as the transfer buffer where seg:offset
is know beforehand.


--
Chris Christoph P. U. Kukulies kuku AT gil DOT physik DOT rwth-aachen DOT de