[movitz-devel] Re: HD driver

Frode Vatvedt Fjeld ffjeld at common-lisp.net
Wed Apr 21 21:34:59 UTC 2004

Peter Minten <peter.minten at wanadoo.nl> writes:

> The only thing is to insert a delay of about 500 nanoseconds. I
> tried using sleep for it but according to grep it wasn't implemented
> yet, so for the moment I'm using (loop for x from 1 to 1000
> collecting x).

Ok. First of all I'd suggest not to use consing as a delay
mechanism. Secondly, if I'm not much mistaken, 500 nanoseconds is 500
cycles on a 1 GHz machine, so that loop expression is probably off by
a factor of about 100 to 1000.

Hm.. are you sure it's nanoseconds? I mean, 500 nanseconds is so
little it's getting complicated to measure with any accuracy, not the
least on older CPUs, or across the PCI bus.

Frode Vatvedt Fjeld

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