[sebhc] HDOS 2 boot problem identified.

Dave Dunfield dave04a at dunfield.com
Tue May 25 14:23:02 CDT 2004

>Hi Dave
> It would seem that if you want to get things working right, you
>need to make index holes appear to your emulator, based on the
>instruction cycles executed. There are two possible choices here.
>You can attempt to add each instruction cycle time exactly
>or you can simply average the instruction count. I don't recall
>there being wait states on things but I don't think it would be
>an issue.
> Emulating the index holes and the 2 ms interrupt based on instruction
>count would mean that the emulator should work for all disk without
>any code modifications.

Hi Dwight,

Thats exactly what I did - it's already posted at:
If you want to try it out. It works not no matter what the actual speed
of the virtual 8080 is. I have now fully implemented the CPU throttle,
so that it runs at a reasonable speed by default, however you can now
disengage the throttle at let the H8 run like a bat out of H*** and
everything still works - however PAM-8 can get a bit "fast" with its
clock interrupt speeded up - (Interesting multiplexing effect on the
rotating dots - at certain speeds they appeare to go backwards!)

dave04a (at)    Dave Dunfield
dunfield (dot)  Firmware development services & tools: www.dunfield.com
com             Vintage computing equipment collector.

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