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HP Forum Archive 09

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fixes for HP-45 and HP-55 simulators
Message #1 Posted by Peter Monta on 12 Jan 2003, 6:32 p.m.

I've been playing with the HP-45 and HP-55 simulators---very interesting! It turns out there are some errors in the assembly code as transcribed from the listings in the patents:

hp45.asm: ---------

99c99 < if a[x] >= 1 --- > if a[xs] >= 1

hp55.asm: ---------

67c67 < ofl: delayed select rom 3 --- > ofl: delayed select rom 5 1601c1601 < ent14: c -> a[x] --- > ent14: 0 -> a[x] 2012c2012 < c + 1 -> c[w] --- > c + c -> c[w] 2025c2025 < c + 1 -> c[w] --- > c + c -> c[w] 3115,3116c3115,3116 < out1: c - 1 -> c[xs] < out2: c - 1 -> c[xs] --- > out1: c - 1 -> c[x] > out2: c - 1 -> c[x]

They were found by hacking up an OCR to look at the '1's and '.'s in the patent TIFFs, so these are probably all the mistakes.

The HP-55 now works under casmsim, at least in ordinary "run" mode. I don't know how to emulate the timer-program-run switch, though. Something to do with S3 or S8, maybe, but exactly what is not clear from the code (which could do with a few comments).

A modified xio.c to display the HP-55 keyboard is available here, along with revised hp45.asm and hp55.asm:

http://www.pmonta.com/calculators

Cheers, Peter Monta


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