HP-25 Subroutines possible?

[Dave Britten]

(06-24-2017 10:01 AM)Dieter Wrote:  I beg to differ. I think subroutines even make sense with 49 (merged) steps, just as they do on the SR56 with 99 unmerged ones. There are essentially two reasons.

Note I said limited use, not no use. I can think of a few situations where a small subroutine or two might benefit such a short program, but I'd have a hard time coming up with one that could use more than three and still fit in 49 steps. I'm not sure how tight the 25 ROM is, but the added instructions would only have to push a return address, then jump to the appropriate GTO routine. RTN would just pop an address, and GTO. You'd probably need one extra register to hold the return stack and a stack pointer.