modular exponentiation?

[ijabbott]

(06-28-2018 12:42 AM)John Keith Wrote:  My HP 50 version,

Code:


\<< PUSH CASDIR MODULO \-> m
  \<< 10 DUP ^ MODSTO 0 1 1000
    FOR n n DUP POWMOD
      IF DUP 0 <
      THEN MODULO +
      END +
    NEXT MODULO MOD m MODSTO POP
  \>>
\>>

is rather slow and clunky due to the HP 50's quirky POWMOD function. It takes about 130 seconds to run, or about 2.5 seconds on the emulator.

I wonder why POWMOD is so slow? Does it do POW followed by MOD?