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From: empty AT sans DOT vuw DOT ac DOT nz (Malcolm Taylor)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: interrupt stops being invoked
Date: 13 Sep 1995 21:03:42 GMT
Organization: SANS, Student Access Network System
Lines: 37
References: <199509120623 DOT QAA22743 AT tinny DOT eis DOT net DOT au> <DEsyFI DOT FC3 AT jade DOT mv DOT net>
Nntp-Posting-Host: tao.sans.vuw.ac.nz
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

Mat Hostetter (mat AT ardi DOT com) wrote:
: ----------------------------------------------------------------------
: void interrupt_memory_start (void) { }

: void my_interrupt_handler (void)
: {
:   ...
: }

: void interrupt_memory_end (void) { }
: ----------------------------------------------------------------------


: and then lock:

: 	(char *) interrupt_memory_end - (char *) interrupt_memory_start

: bytes, starting at:

: 	(char *) interrupt_memory_start

: Of course, there's no guarantee that this will work (I think even
: casting a function pointer to a char * is forbidden) but it happens to
: be the case that this works with the latest djgpp (just make sure all
: of your functions are non-static).

It will work, casting a function pointer is allowed (just another type of 
pointer, nothing special). There are a few other things to watch for. 
Make sure you do not compile with optimizations (esp. not -O3) as these 
can shift code about. If your interrupt routine uses any static variables 
(ie in the data seg) then lock these as well. And a question. Is the 
stack locked? (It seems like a funny question to ask, but I can't think 
of an answer)

Malcolm

: -Mat