Coming soon - HP-86 emulator



I am currently in e-mail contact with an HP-86 fan who is writing a HP-86 emulator. He said he has based this on an HP-71/HP-75/Capricorn emulator.

He has also produced a disassembler.

One area he is stuck on is input / output, this is very poorly described in the Assembler ROM manuals. I have heard there was a manual called something like 'Input / Output Assembler' that may help, but I have yet to see a copy.

If anyone else has an HP-85/86/87 emulator on the way it might be worth pooling ideas.




no, I can't help you with your question.

But, you wrote :

> He said he has based this on an HP-71/HP-75/Capricorn emulator.


Note that the HP-71 and the HP-75 are quite different machines.

The HP-71 has the original Saturn 4bit CPU,

whereas the HP-75 has a Series 80 compatible 8bit CPU.

So an HP-75 emulator could be used as base for an HP-86,

but I doubt an HP-71 emulator would do;-)





Well in fact I started with a emultor for HP42s to have a nice program structure, but I rewrite all the saturn stuff as capricorn stuff.

In fact there are 2 areas where I got problems, of course the IO of the 86/87 (the rom I got thanks to John) and also the behavior of the CPU in DCB mode when non-DCB number are used. The cpu is quite complicated due to the numerous status bits not so well documented in the HP85 assembler manual.

The emulator half-works actually, I got alpha-display, keybord, I can enter lines of programs, make some basic computation but actually I CAN'T display any numerical result !!! (DCB bug, or extended controller bug I think, need more work)



You may download a PDF-Scan of the HP-Series 80 I/O Assembler-Manual from



BTW in the PPC COMPUTER JOURNAL V3N3 (May/June 84) jim Horn mentioned that the following manuals were available for the HP-75C:

V1: ROM Description & Entry Points

V2: System Listing (Source Code)

CPU Description

These manuals were to be sold by the PPC and should provide a lot of information that is applicable to the Series 80 computers as well.

Has anybody seen these manuals?



keywords could be 'Jake Schwartz' and 'Philly Chapter' ;-)

IIRC, Jake used to offer the PPC CDROM archive set, too.


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