Date: Sat, 14 Jan 1995 22:55:22 -0500
From: Cuthalion / Sliced Bread <enrico AT max DOT tiac DOT net>
Subject: Unsupported Int?
To: djgpp AT sun DOT soe DOT clarkson DOT edu

  Several weeks ago, I tried to post about this problem, but instead 
somehow managed to unsubscribe myself to the list.  Let's hope I get more 
helpfull results this time.

  I am writing a .MOD file player for the Gravis UltraSound, using GNU 
C++.  My first problem is that the GUS SDK, although it has Watcom 32 bit 
libs along with the BC and MSC libs, all of the source is for BC, and I 
don't really feel up to porting the whole mess.  So, I rewrote what I 
needed into a somewhat less user-friendly, but sufficient, chunk o' 
source.  So that problem's out of the way.  Then I wrote some loading and 
basic [timer IRQ driven] playback routines.  But the problem is that with 
certain files, it crashes, real unfriendly-like.  It's sort of hard to 
debug, since I never see a call-frame traceback, and everything that 
happens happens in interrupt vectors, and thus can't even have debugatory 
printf's in it.  All it does is say "Unsupported Int 0x00" and then one 
of two things happen.  

1)  Sometimes it just crashes.  Right there, in the middle of the printf 
that the "Unsupported INT 0x00" error message interrupted.  When it does 
this, it often does other weird stuff.  (Putting a couple high ASCII 
characters (in brilliant technicolour) on the screen, turning on the PC 
speaker, etc) 
 
2)  Other times, and this is REALLY strange, it just keeps going with the 
main program stream, but with all interrupts cut off, it seems.  None of 
the values get incremented, none of the playback calls are made, but the 
while (!kbhit()) printf("%d, %d/%d: %d %d\n", A, bunch, of, status, 
vars); keeps going.  Any keyboard input (^C, Ctrl-Alt-Del included) are 
ignored.  

  I see no pattern that might predict which of these crashes occur.  Both 
have happened with the same input file. 

  So, if anyone tells me what's wrong, I'll give them $47 000 000.  
(Offer only valid while supplies last.)  

  Thank you.  

  -Jesse