Path: utzoo!attcan!uunet!husc6!cmcl2!nrl-cmf!ames!pacbell!att!chinet!saj From: saj@chinet.UUCP (Stephen Jacobs) Newsgroups: comp.sys.atari.st Subject: Turning off vertical blank interrupts Keywords: interrupts traps vbl Message-ID: <5888@chinet.UUCP> Date: 26 Jun 88 02:56:46 GMT Organization: Chinet - Chicago Public Access UNIX Lines: 9 A while ago I asked what would happen if I set the interrupt level of an ST high enough to disable the vertical blank interrupt. The responses were not unanymous, but I got the idea that there should be about a 5% speed increase, against the possibility of crashing GEM. I just tried it in a computation-intensive GEM application. The good news is no crash. The bad news is only maybe a 1% speed-up. By the way: I tested that the vbl interrupt was really disabled by flipping the switch that controls whether my Thomson Ultrascan monitor is claiming to be color or mono: monitor change is detected in the vbl routine.