HP-12C Platinum Version 02 calculator from 2010 week 21?

[BobVA]

(07-11-2015 02:21 AM)rprosperi Wrote:  ... I'd speculate (sounds better than guess...) that this is due to the more complex programming model in the 15C design, maybe calculating the offset to jump back each time, while the 12C just jumps to a known offset, or something along those lines.

I'd speculate your speculation is correct :-)

Either of the ways to do the branch in the 15 has some overhead. Label searches proceed forward in program memory - the wrong way in this case - and indirect branching to a line number involves a register load and whatever complexity is involved in converting that floating point value into a line number. Both seem a lot more complicated than just resetting the program counter in the 12.