Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hpda!hpcupt1!dclaar
From: dclaar@hpcupt1.HP.COM (Doug Claar)
Newsgroups: comp.sys.ibm.pc
Subject: Precise loop timing on PC?
Message-ID: <5930024@hpcupt1.HP.COM>
Date: 7 Feb 89 21:45:37 GMT
Organization: Hewlett Packard, Cupertino
Lines: 16

This has probably been discussed before, but is it possible for the PC
to execute something precisely and repeatedly, at or near the clock
speed? I have a little 75 clock loop that I would like to take 75
clocks EVERY time...no interrupts. It is important that the I/O port
referenced is accessed in uniform time slices. I tried doing a CLI
and also setting bit 7 of port 0A0H and 070H (I saw differing docs
on which one was supposed to control NMI), but these steps didn't
help. Can this be done?


Thanks,

Doug Claar
HP Computer Systems Division
UUCP: mcvax!decvax!hplabs!hpda!dclaar -or- ucbvax!hpda!dclaar
ARPA: dclaar%hpda@hplabs.HP.COM