New firmware for the Swissmicros DM15L

[Johnp_g]

(10-04-2024 06:29 AM)jebedeo Wrote:  Hey guys, here's another beta. Not much to it, just the f CLEAR PREFIX fixed.

For example, sqrt(2) = 1.41421356237309504880... but if you do it with this firmware and use f CLEAR PREFIX you will see "X: 1414213562373095168. ", so the first 16 digits are correct, and after that it's just noise. So perhaps that's all the calculator should show. I'll read up on floating point numbers a bit more, but for right now know that you can't trust all those digits

My thought is that the 16 "accurate" digits is all that should be displayed, as the trailing noise digits add nothing and could mislead.

For example, using a number that makes the noise visible

Code:


1 
ENTER
6
/

This displays as 1.667 in FIX4 and fPREFIX shows

1666666666666666496

The trailing 496 is obviously garbage, and should be hidden.

For a number like PI, e or SQRT2 or any calculation result with many digits, it's not so obvious, as the digits may have no obvious pattern.

You don't want to be seduced into thinking "the 18th digit of PI is 8" because my calculator is super precise and accurate. Curtailing at 16 digits gives confidence that everything shown is correct.

If it costs too much in terms of code size, to add the extra code to curtail at 16 digits, then saving memory and the ability to add the Solver (and Integrate) should take precedence, and fPREFIX left with the user to disregard the last few digits themselves.

Thanks for all you've done so far. My DM15L was largely unused as it was mostly a curiosity for me to have a modern "HP15C".The complex number handling, archaic programming display of keycodes and the sedate speed meant I had better, if larger and more expensive, calculators to use. Now the DM15L has been given a new lease of life and is useful for pretty much anything I need in day to day life, at work or in my other hobbies. And the Voyager form factor is cool, so that it's great to carry it around everywhere. I'm very happy to have this firmware to pep up my forgotten DM15L.

Cheers,

John