Date: Fri, 6 Jan 95 13:16:09 MST
From: craig AT sunspot DOT noao DOT edu (Craig Gullixson)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: Data acquisition with djgpp??

>Hi all,
>
>Has anybody tried using djgpp to control one of the popular data
>acquisition cards (Nat. Inst.; Scientific Solutions/Tecmar; Metrabyte
>...)?  How hard would it be to convert C libraries written for bcc that
>control the cards?  Obviously one would need to handle different-sized
>data types, but I'm wondering whether there's some particularly nasty
>sticking point.
>
>Thanks in advance,
>D
>
>--
>David J. Perkel					perkel AT slice DOT etho DOT caltech DOT edu
>Division of Biology, 216-76
>California Institute of Technology
>Pasadena, CA  91125
>Tel: (818) 395-6816   FAX: (818) 449-0679
>

I've just finished with converting two of the libraries from a
Symmetric Research DSP board. The libraries were set up to be
compiled using bcc and msc. Besides the should an int become
a short question, I found most of the conversion to be pretty
straight forward.

On semi-nasty thing was converting inline assembly.  In the end,
I ended with one line of inline assembly replacing the rest with
libc and libpc library calls.  The libc stuff replaced file I/O
calls that were in assembly for using the library with fortran.
The libpc calls were mostly inport and outport calls.

Most of the other problems I had were where there were sloppy 
code problems containing assumptions about incrementing pointers
properly and assumptions about initialization of memory chunks and
string pointers that didn't fly in a strict ansi enviroment.

I think that any board that communicates to the PC using the
PIO ports should be pretty straight forward to convert using
the libpc library routines.  It is important to exercise the system
pretty completely using whatever examples that came with it.

Note: I haven't had the need to use the graphics library yet ---
when I do get around to converting it, I expect to rip out most/all
of the low level graphics routines (mostly assembly) and replace
them with libgrx calls.

________________________________________________________________________
Craig A. Gullixson
Senior Research Associate		INTERNET: craig AT sunspot DOT noao DOT edu
National Solar Observatory/Sac. Peak    PHONE: (505) 434-7065
Sunspot, NM 88349 USA