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Hi, some recent news about my FPGA emulation.

The CPU is ok, the timers too, the keyboard also.
Now the extended controller is ok.
So it can emulate an HP85B with MASS ROM and ELECTRONIC DISK

More infos : http://sites.google.com/site/olivier2smet2/hpseries80/fpga-hp85b

I will start IO processor and HPIB emulation for SD flash based disk.


Edited: 26 May 2010, 2:25 p.m.

impressive! and most interesting.

i had a read of your emulator code and, presumably, you've implemented the 80 series cpu instructions in vhdl? so how fast is it running. im thinking it ought to be amazingly quick, any benchmarks?

does this open the feasibility of re-implementing the hardware of other processors like that of the 41 or the saturn - but at modern cpu clocks !!

For the CPU it's not done from the software emulator code. It's based on the hardware description of the system in an HP patent. The described microcoded machine is coded in verilog.

Actually it's running at real speed (625 kHz) for debugging reasons but the actual code should run at x4 speed and perhaps at x10 which is the maximum this board could achieve (50 MHz base clock with 110 ns RAM). As the cpu can access to memeory every cycle, the limit is the RAM speed (plus some timing delays).

In fact a pure software emulator could be faster but not as energy efficient :) (2 GHz system to have x50 speed)

The IO system is more based on the behavior from the software emulator which is enough to have a running system.

For other architecture, I don't know if the hardware description is detailled enough to permit this kind of emulation.


Edited: 27 May 2010, 1:09 a.m.

Very very amazing. Even the error of my HP-85 are ported (self test). Looks very nice.