Which calculators had no known bugs?

[[kby]]

(08-05-2017 08:55 AM)Sadsilence Wrote:  Not a real bug, but all classics and most woodstocks are not able to calculate 2^32 correctly. They tell us 4294967304, correct would be 4294967296. Even more strange, that HP-19C can, HP-25 cannot.

The HP-29c does it correctly as well and so does the 97s (and presumably the 67 and 97).

There was a significant algorithm change between the 25[c] and 67/97: Machines prior to the 67/97 appear to use a logarithm-based algorithm; later machines have exceptions built in for certain cases. The primary visibility on those machines is the ability to raise negative numbers to integral powers, which can be done by multiplication as an alternative to using logarithms. This requires soecial-casing integers, do I expect the 2**n issue to use the multiplication code as well.

The only intervening machine is the HP-27, which oddly has no y**x function built in.

In addition to multiplying directly, using x**2 repeatedly also works.