HP-91 Simulator

[Joe Horn]

Shift Sigma+ stopped working correctly. Instead of performing Sigma- as it should, it instead performs Sigma+. Oh, those pesky shifted funtions!

EDIT: Indeed, many shifted functions seem broken, e.g. 10^x, LOG, SIN^-1...

EDIT: 0 / --> Error... which cannot be cleared except by turning the 91 off and back on.

EDIT: RCL and STO no longer work.