SR-52 programming tip

[Gene]

What? None of you program your Texas Instruments SR-52 these days? :-)

from TI PPX V1N1 (essentially their version of Key Notes):

"Calculations with fixed decimals are usually slower than those with floating decimals. Fix 0 is the slowest with speed increasing as the number of decimals is increased.

Strangely, Fix 8 is faster than floating decimal, by as much as 10%, even for simple whole numbers, and can be as much as 30% faster than Fix 0."


Thoughts:

1) If you are writing an SR-52 program and do not intend to round numbers off by the type of trick that involves EE INV EE and a change of FIX mode, then put a FIX 8 at the start of the program and then at the end invoke the FIX setting you desire at program end. May speed up execution up to 30%!

2) This must relate somehow I guess to the TI-58/59 fast mode. Users in the TI club found that the speed of the calculator increased dramatically if they could trick the calculator into running a user program in the same way it ran a program in a plug in rom. A user program took a number from the display and executed a program step. It would convert the displayed number into an internal representation, execute the step and then convert it back every time, every step. This greatly slowed execution down compared to the way the TI 58/59 ran plug in rom programs. With those, the calculator did not convert the number's representation with each step but only when it stopped or paused execution. Since library programs were non-interruptible, this made a lot of sense. It was noticed when users copied programs from the roms into ram and noticed they ran slower than before.

3) Since the SR-52 runs faster in FIX 8 than floating or FIX N, there has to be some sort of connection.


By the way, here are my notes on TI 58/59 FAST mode presented at a recent HHC conference.

Fast Mode

What? You don't come to those? :-)