Date:	Wed, 26 Apr 1995 01:31:20 -0300 (ADT)
From:	Bill Davidson <bdavidson AT ra DOT isisnet DOT com>
Subject:	Re: Chaining real-mode interrupts
To:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
Cc:	djgpp AT sun DOT soe DOT clarkson DOT edu

On Tue, 25 Apr 1995, Eli Zaretskii wrote:

> I will try to make it more clear, but please also consider what, if
> anything, needs amendment after you've solved your problems.  If you
> cannot do it right by reading the FAQ and the docs, something *must* be
> missing.
> 
Thanks for the pointer to pctime12.zip.  I examined that code and noted 
that the only significant difference from mine was that the 
_go32_dpmi_registers struture whose address is passed to 
_go32_dpmi_simulate_fcall_iret() was a global, whereas I was allocating 
an auto in my handler (which is how the info page looks).
I changed that, and it worked!  Re-ran the program a couple of times to 
be sure, and the results were a bit erratic :-(.  Still, it wasn't seg 
faulting, so I applied the same fix to my kbd handler and 
un-commented-out (commented in?) the line that set the RM kbd handler.  
Program segfaulted on start-up (never even got to the start-up screen). :-(

The program sits in a pretty tight event loop, and I noticed that with 
'topline' in my GO32 variable the 'P' and 'R' at top left both sat there 
all the time, just barely flickering.  Should this tell me something?  It 
looks like the processor is mode-switching very fast (maybe 18.2 times a 
second?).

Incidentally, just to make sure that the compiler/library were OK I 
recompiled the pctime12 sources, and the program ran fine, which was 
really irritating!  "My" program is one I am porting, and I am beginning 
to suspect that there is some weird interaction going on with some other 
function, although I can't imagine where.  When it segfaults I always get 
_two_ "Segmentation Violation" messages (sometimes more), and symify 
can't make any sense of the tracebacks (which either show just one 
address or just two, the bottom one in that case being NULL).

*Sigh*  I have the depressing feeling that I am going to find the problem 
here some day, and it is going to be really simple...

Thanks for all your help.

Bill Davidson

PS -- Have you been seeing multiple copies of my/your messages?  I just 
received a "new" copy of my post from Monday.

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