Xref: news2.mv.net comp.arch.embedded:8650 comp.os.msdos.djgpp:5154 comp.realtime:7774 gnu.gcc.help:7181
From: tibors AT opera DOT iinet DOT net DOT au (Tibor Sashegyi)
Newsgroups: comp.os.msdos.djgpp,gnu.gcc.help,comp.arch.embedded,comp.realtime
Subject: GDB: target remote i386
Date: 18 Jun 1996 14:12:34 +0800
Organization: iiNet Technologies
Lines: 47
Message-ID: <4q5hci$2me@opera.iinet.net.au>
NNTP-Posting-Host: localhost
Summary: GDB: target remote i386
Keywords: GDB target remote i386
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp


I have used GCC/GDB for a while in the BSD world, but now I would
like to use DJGPP v2 for embedded system development targetting Intel
386 processors. Compiling and debugging under Windows 95 work just
fine.

My problem is how to use GDB for remote debugging. The info pages
are a bit unclear about how to specify the PC's COM ports. I had
a look through the GDB sources and the file ser-go32.c refers to
an external TSR called asynctsr.com which I found to be part of
the archive v1tk/aeasy102.zip. When I unzipped the archive and run
"asynctsr.com 1" the driver installs some interrupt vector at 0:0x2c.

I then run the test software via "go32 gtest" but the test software
dies with a SIGSEGV when it is checking for the presence of the 
interrupt vector at 0:0x2c. It does the check by adding the address
to 0xe0000000 and this seems to be the cause for the SIGSEGV. How
does the DPMI deal with this address. Is this maybe a problem with
Windows 95's DPMI?

My questions are:

1. Does v2gnu/gdb412b.zip support remote debugging or do I have to
   rebuild GDB to add the support? If I have to rebuild for remote
   debugging, is there a FAQ or any other info available to help?

2. Is asynctsr.com from the v1tk the right vehicle for what I want
   to do?

3. Has anybody done remote debugging for Intel 386 based embedded PC's
   using DJGPP and GDB? If yes, please share your experiences.

4. Has anybody got a i386-stu.c stub and startup code for a 386 
   based embedded PC to give away?

5. Is there a problem with implementing a serial driver for the PC
   directly in GDB?

Please reply by email and I will summarise.

Thanks and best regards

Tibor

Email: tibors AT iinet DOT net DOT au
       tibors AT iores DOT com DOT au