Date: Fri, 21 Feb 1997 01:04:17 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, eivind@dimaga.com Cc: brian@awfulhak.demon.co.uk, hackers@freebsd.org Subject: Re: Screen flickering Message-ID: <199702201404.BAA02379@godzilla.zeta.org.au>
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>>Otherwise, the best that can be done is probably something like: > >Nope. If there is a *timer* interrupt available, you can use it to create >a vertical blanking interrupt by tweaking start point and delay. 'Nuff said? Well, there isn't a timer interrupt available, and keeping a timer interrupt in sync would require large code and/or large runtime overheads. For extra credit, use the standard timer to provide interrupts at HZ Hz, (normally 100), the screen refresh rate, and whatever is requested by acquire_timer_0() (which should be a multiple of 100 Hz <= 16000 Hz). The HZ Hz interrupt must not have significantly more drift or jitter than it does now. Well, there isn't a timer interrupt available :-). Bruce
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