[sebhc] Emulator evolution (& new download avail)

[Dwight K. Elvey]

>From: "Dave Dunfield" <dave04a at dunfield.com>
>
>>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.

Hi
 I see you stole my thoughts before I entered them. One thing you might
look into is being able to change the 2ms interrupt back to a true
2ms for code running in different areas of memory. This might be useful
for games and such.
 It is a pain that the disk I/O uses both timer delays and code
execution delays.
Dwight

>
>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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