The elusive negative zero on the HP 30b

[rprosperi]

(05-12-2021 08:37 PM)FabioBrasil Wrote:  This has nothing to do with settings, I believe.

But it probably is because you are treating it like classic RPN and doing this:

a) 55555 [+/-] [Input] [shift] [Y^X] => 0.00

While for Entry RPN (used on the 30B) you must do this:

b) 55555 [+/-] [Input] 55555 [+/-] [shift] [Y^X] => -0.00

I also think it has nothing to do with it. Perhaps that ² (from SW 4 5 2010 ²) explains something.
I did it both ways a) and b) and the result was 0,00

You may be right... Checking my version again, the small raised number on the right edge is a 1.

So... maybe HP did consider this "-0.00" as an invalid, or at least undesirable, display and changed the f/w to prevent it.