Nonpareil status

[brouhaha]

After a lot more redesign, coding, and debugging than I expected, Nonpareil has support for a row of the PICK-scanned keyboard in the 19C and 97 to also drive either a row line of the ACT keyboard scanner (19C) or one of the card reader controller external flag inputs (97). That's how HP implemented the feature that holding SST, BST, or R/S pressed shows the program line. The PICK chip doesn't have a way to sense that a key is still held down, so they had to do this weird hardware hack. The programmable calculators that don't use the PICK chip (25, 25C, 29C, 67) don't need the hardware hack as the ACT keyboard scanner does allow sensing key still down.

This is also used on the 19C for the paper advance to keep going while the key is held.

I have the 92 mostly working, though I don't yet have suitable graphics for it. However, some financial calculations crash the calculator, including the example on page 30 of the Owner's Handbook.

I'm not yet ready to do another Nonpareil release, but it's in the Github repo for those feeling adventurous.

The 19C display formatting is wrong, which seems surprising since I thought it worked the same as Topcat models (and unlike the 29C, which works like the other Woodstock models).

There's long been a known bug with the HP-55 "dot" registers. I found a general problem with the Classic series in how RAM is handled that I think explains that, but I haven't fixed it yet. There's something wrong with the 45, because after reloading a saved state (e.g., after exiting Nonpareil and restarting), the display does weird flikering and it has to be reset. Perhaps some state is being saved incorrectly, or there's some necessary state that isn't being saved at all.