HP-25 vs. SR-56 - HHC 2016 Follow-up

[Dieter]

(10-10-2016 02:42 AM)Gene Wrote:  What Jim Davidson found after analyzing a lot of pretty amazing HP 25 programs was that on average, there were about 1.6-1.7 keys per step, so that 50 merged was equivalent to about 80-85 steps on the SR-56.

Please note that we are talking about two slightly different figures in this thread. One thing is the "keys per step" ratio, the other thing is the "HP steps : TI steps" thing.

For instance, STO+1 requires three keys on most HPs and two (SUM 1) on the SR-56, while it takes one step resp. two steps in program memory. So a key-to-step-ratio of 1,6...1,7 in an HP25 program is one thing, and a TI-steps-to-HP-steps-ratio of 1,7...1,8 is another. The latter consists of both the more merged program steps as well as the more effective way things can be done in RPN, e.g. intermediate results do not require an "=" or even "(" and ")", tests can execute or skip any command instead of merely jumps, etc. While on the other hand special commands like the TI59 OP2x and OP3x increment/decrements or not being limited to one single indirect register will change the figure in favor of TI.

So a fair comparison of the two worlds has to consider more than just the more or less merged program steps. For the HP67/TI59 case, I think the 4:7 ratio fits quite well.

Dieter