HP-97 Emulator

[teenix]

(01-15-2017 04:26 AM)Joe Horn Wrote:  Oh no, please don't "fix" this! It's a bug in the original '67 and '97 which really should be kept. Here's what happens: After turning on, pressing Sigma-Minus followed by X-bar puts a negative zero in stack register Y. This can only be seen by executing the STK command on the '67 (or by executing PRINT STACK on a *real* '97 or on a very good emulator). If %CH is executed with that negative zero in Y, the poor machine attempts to divide by zero (the negative sign makes it think it's not zero) and of course it crashes.

Some '97 emulators (e.g. "RPN-97 Pro" from cuveesoft.ch) generate an "Error" when division by negative zero is attempted. I personally dislike that, since IMHO the best emulators act exactly like the original calculators, bugs and all.

I quite agree, it will stay as is :-)

I put a little note about the bug on the front page of the help file and just uploaded a new HP97.zip.

PS Thanks for the kind words, the emulator does print out the stack with -0.00 in Y. You can also see this value in the Y register when the debug screen is open.

cheers

Tony