HP Prime Screen Dimming Hack

[Joe Horn]

(09-06-2018 01:52 AM)JDW Wrote:  Joe, the top of page 582 in the HP Prime User Guide says the default wordsize is 32. I just checked my Home "Settings" and confirmed that it is 32. Why then is "30" the wordsize for TDim? (I am just curious.)

MY GUESS: It's permanently fixed at 30 bits because otherwise it would be at the mercy of the 'Bits' system variable, which would be disastrous if 'Bits' were very small, thereby causing instant dimming. Why they wanted to let the user specify up to (2^30-1)/1000 seconds before dimming, I don't know, but allocating more bits than that would clearly have been silly, so they capped it at 30 bits.

Disclaimer: Tim and Cyrille know the answer. I'm just guessing here.

EDIT: Wild second guess: Maybe the real-time clock's system-interrupt word is 30 bits wide?