🚀 go-pugleaf

In article <1992Aug3.210504.57823@cc.usu.edu> sl8nl@cc.usu.edu writes:
> detect the retrace with an interrupt, rather than polling for it. 

>
>>Question:  If you set the retrace up as an interrupt (possible...by modifying
>>the timer interrupt to run at 60 times a second), wouldn't you still have

  I think the original posting was about the user of the VGA Card's hardware
interrupt, not the timer chip.  The timer chip wouldn't stay in phase with the
video retrace, and therefore wouldn't help.
  The VGA card does have an interrupt line which can be used for this, but I
wouldn't use it if you plan to distribute the program to others.  Since the
PC stupidly has so few interrupt lines, this line get used for all sorts of
other things.  Infact this video int is always disabled normally, and
I've never heard of a program that uses it.  I have a feeling that this would
be the kind of thing that would fail on about 1/2 the people's computers.
  Anyone else out there have any experience in this?

  I believe Micheal Abrash's book covers the use of the interrupt line,
certainly Ferraro's book would.

                                         -Kevin

-- 
	Kevin Stokes
	Duke University Dept. of Physics	kds@phy.duke.edu
	Durham, N.C.      27706