Hi Rob,
Simh device wait units are instructions.
Usually a device has no specific knowledge about the significance of wall time
vs instructions. To help solve this problem some methods exist to specify wait
times which correlate with the simulated machine's clock ticks which are
dynamically calibrated to produce a number of instructions per unit of time
(clock tick). Devices usually behave well if wait units are aligned on clock
ticks and doing this helps produce better 'idling' behavior. A device which
wants to wake up on every simulated clock tick would code the following:
extern int32 tmxr_poll; /* calibrated delay */
sim_activate (uptr, clk_cosched (tmxr_poll)); /* reactivate */
Good Luck,
- Mark
From: [email protected] [mailto:[email protected]] On
Behalf Of Rob Jarratt
Sent: Sunday, October 07, 2012 10:05 AM
To: [email protected]
Subject: [Simh] Device Timing Question
The device I am emulating appears to be running too fast for the driver that
uses it and I need to get to grips with device timing in SIMH. I have never
fully understood the use of sim_activate, in particular what are the units of
time that are passed to this routine?
Thanks
Rob
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