14 Nov
2005
14 Nov
'05
8:06 a.m.
Allison wrote:
Everyone has done the PC emulating whatever. Why not
take a
single chip micro and use that to emulate another micro as
hardware? Same idea maybe slow but for a lot of things speed
is not the whole world.
I did it on paper for PDP8 and it was possible using an 11mhz
8049 to come within 1/10 the speed of a real 8. I guess a
36bit machine could be done as well (though really slow.).
Also a front pannel could be programmed into it as well
(maybe a speed hit). Any cpu that gets an instruction from
memory and then executes it can be emulated that way.
1/10 the speed of a real PDP8? Really? That is fast indeed!
My emulation of a PDP8, running on a 68B09 (at 2 MHz) gets to
approx 1/60 of the real thing. I measured that by running some
diagnostics. The diag says "bell rings after approx 5 seconds),
and timed how long it took on my 68B09...
I am sure that when I remove the front panel code things run
faster. The front panel requires time to update. But running
the emulation without the front panel is no fun.
- Henk, PA8PDP.
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