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From: acmfiu@serss0.fiu.edu (ACMFIU)
Newsgroups: comp.sys.apple2
Subject: heartbeat interrupts
Message-ID: <1995@kluge.fiu.edu>
Date: 13 Jan 91 03:17:43 GMT
Sender: news@kluge.fiu.edu
Organization: Florida International University, Miami
Lines: 74

I have the following inline asm function to handle HeartBeat interrupts. my
main purpose for using it is to catch keypresses and pause control of the
program in progess. Then, I just wait for another keypress. Also, if the
user presses oa-period, then the program should immediately end, regardless
of where it is.

However, when i oa-period 3/4 times, the computer crashes. can anyone
suggest a better (i.e. WORKING) solution to my problem.


asm void
check_key (void)
{
  dcl 0
 count: dcw 10
  dcw 0xa55a

  phb
  phk
  plb
  php
  rep #0x30
  lda #10
  sta count

  sep #0x20
  lda >0xe0c000
  bpl end
  cmp #0xae
  bne wait
  lda >0xe0c025
  and #0x80
  beq wait
  rep #0x20
  lda >0xe0c010
  jsl raise_signal
  bra end
 wait: lda >0xe0c010
 rdkey:  lda >0xe0c000
  bpl rdkey
  lda >0xe0c010
 end: rep #0x20
  plp
  plb
  dcb 0x6b
}

void
raise_signal (void)
{
        raise (SIGTERM);
}

void
bye (int sig)
{
	fclose (global_file);

	DelHeartBeat (check_key);
	exit (1);
}

int
main (int argc, char **argv)
{
	signal (SIGTERM, bye);
	SetHeartBeat (check_key);

	<blah>
}

-----------------------

albert chin ... acmfiu@fiu.edu