Of course you are right and it has to do with internal precision and formula used for

all exponantial calculations. But 2^x values are so common to programmers and so easy to handle for processors of all kinds, that I somehow expected a special treatment.

(08-05-2017 04:36 PM)Dieter Wrote: (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.

These early calculators do not feature the extended (13-digit) internal precision routines of the later models (AFAIK since mid 1976). Since y^x is evaluated via e^(y*lnx) the roundoff error of these operations may show up in the last digit(s). This can even happen with newer calculators for very large results, cf. the 15C Advanced Functions Handbook, p. 150 ff.

(08-05-2017 08:55 AM)Sadsilence Wrote: Even more strange, that HP-19C can, HP-25 cannot.

Sure, the 19C is a later model with extended internal precision. But even this is not always sufficient: try 3^201. ;-)

Dieter