🚀 go-pugleaf

In article <1993Feb17.102315.1798@aber.ac.uk> auj@aber.ac.uk (Alun Jones) writes:
>Sorry if this is the wrong group or I am being hopelessly naive...
>
>I am running GCC 2.2.2d on a PC. Until recently I've been using Borland
>C, but would like to port my code to GCC to avoid the brain-dead segmented
>rubbish they call real mode. My problem is that I have to access a driver
>to talk to a DSP processor using DOS interrupts. Whenever I try this I
>get an exception from the program. Using interrupt 0x21 to find the
>required interrupt vector gives exception no. 0x21, likewise interrupt
>0x65 (to access the board) gives exception 0x65. I have a suspicion that
>I'm asking for the impossible here, and that real mode calls can't be
>made under the GO32 extender. If anyone could confirm that or give me
>a useful counterexample I'd be very grateful,

[disclaimer: I've switched from dos to os/2, and no longer use djgpp, so
some of this info may be out of date, or misremembered]

There are basically two approaches to doing this type of hardware manipulation.

1) modify the dos extender (go32).  An example of doing this are the 
   lgrx.a functions (interrupt driven mouse routines instead of polling, 
   call back functions, etc).  Probably the only thing I would have 
   recommended being added using this method would be generic signal
   handlers.  NO INTERRUPTS USING THIS METHOD! go32 is running tight on
   real mode memory, and careful consideration should be made before
   adding anything to it.
2) TSR method.  the file aeasy10x.zip has an example of this.  Basically, 
   a generic interface is provide, and the TSR provides the specific 
   interface to the hardware.  While asy is for asychronous comm port 
   access, it should work with *any* hardware driven interrupts.


FYI, there is a mailling list dedicated to djgpp, go32, and apps written
for it.  It is pretty active (last I was subscribed to it, anyway), and a
pretty good forum for this type of discussion.  Be warned, DJ has just 
become a new father and doesn't have a lot of time to spend on extra 
development at the moment, though I beleive someone else is doing some
work on it (such as adding dpmi support), though I can't remember who 
it is (Alan Eldridge, I *think* , the 'ae' from aeasy above).

Info on the list is in the documentation that comes with djgpp, or mail
me and I will send you info.

regards,
mrc
-- 
Mike Castle .-=NEXUS=-.  Life is like a clock:  You can work constantly
  mcastle@cs.umr.edu     and be right all the time, or not work at all
S087891@UMRVMA.UMR.EDU   and be right at least twice a day.  -- mrc
    We are all of us living in the shadow of Manhattan.  -- Watchmen