[sebhc] Emulator evolution (& new download avail)

[Dave Dunfield]

>How rude!  :-)

Yeah - I though so!

>>So - looks like I will have to implement the auto-calibration function to
>>set the CPU speed when the emulator starts.
>
>Darn.  It's nice having an extra-fast H8.   :-)  Maybe that could be 
>switchable, so you could turn on "max speed" after boot, or start up that 
>way if your disk image has the new driver?

I have decided to completely change the way I do my clock simulation - instead
of letting the 8080 run "wild" and regulating the frequency of interrupts to
approximate real time, I now generate the clock interrupts based on the number
of 8080 instructions executed, and now I regulate the speed of the 8080 to
approximate real time.

This has a distinct advantage that the virtual envuironment always sees correct
"real time", even if this has nothing to do with the outside world. Thus you
can speed up or slow down the entire system (I have also provided a performance
tuning parameters to let you adjust the interrupt frequency relative to the
simulated CPU speed so you can basically tweak it any way you like).

I have uploaded a new version of the simulator to:
   http://www.dunfield.com/pub/H8H17.ZIP

This version will self-calibrate to a reasonable CPU speed - see the HELP info.
for details on the new options.

This version boots HDOS 2.0 with no trouble. To test the speed regulator, I
ran it on a 286 - it took a while, but HDOS booted just fine.

Btw1: if you want to see a FAST H8, try: H8 XS=0 XT=0 ...

Btw2: I notice that the HDOS 1.6 disk contains text to the effect that it has a
      special driver for the Macintosh emulator? - do anyone know what this is
      about?


>>It may not be obvious, but the L= command line option can load code/data
>>anywhere, even in ROM space.
>
>That works too!

This new version has this fixed so that it does work - you can use L=
to load your own ROM. I have also included my latest H8T in the ZIP.


>I wonder if you'd be willing to do one thing in your emulator that would 
>diverge from reality?  Add a stub so that a device driver could get access 
>to files in a specific folder on the PC.  This would effectively create a 
>virtual HD on the PC.  What do you think?  :-)

Does HDOS support the concept of accessing files on a device (not through
the HDOS filesystem?) - this would be similar to the redirector support in
DOS, and I would be suprised of HDOS had this. Otherwise HDOS will want to
read and write directory entries, allocation blocks etc. from the device.

If your goal is to move files in and out of the HDOS disk images, then why not
write a utility like my ADI that I include with the Altair simulator to read
and write files from the PC into/outof a disk image.

Is there clear documentation available on the format of an HDOS disk image?
(I can guess the answer to that one).

I have to be careful --- too many more features, and the emulator will grow
out of TINY model!

Regards,
Dave
-- 
dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.
                http://www.parse.com/~ddunfield/museum/index.html

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