/cch/ - Casio Calculator Hacking

the function that user202729 named as "num_invalid__" is unsurprisingly NOT a function that checks if the number is invalid
how it works is surprisingly simple, after testing in an emulator i realized it's a fucking sign checker
it returns 1 for zero value, 2 for negative, 4 for positive, 0xf0 for unsupported number formats (namely matrix/vector pointers and ERROR values)