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+--- Thread: HP 12C Date calculations (/thread-12860.html)
HP 12C Date calculations - detron - 04-24-2019 03:50 PM
can anyone shed any light on how the HP 12C does date calculations?
not how to do them, I get that. I am curious how this might have been achieved on a calculator that has such limited ROM space. what type of programming would yield these features?
the fact it even returns day of the week, and has a large date range it supports is a marvel to me.
RE: HP 12C Date calculations - Thomas Okken - 04-24-2019 04:17 PM
I don't know the specific algorithms used by the 12C, but compared to the other functionality in that calculator, date calculations are pretty easy. Take a look at the greg2jd and jd2greg functions here: https://fossies.org/linux/free42/common/core_commands7.cc (lines 207-233)
RE: HP 12C Date calculations - detron - 04-24-2019 04:26 PM
(04-24-2019 04:17 PM)Thomas Okken Wrote: I don't know the specific algorithms used by the 12C, but compared to the other functionality in that calculator, date calculations are pretty easy. Take a look at the greg2jd and jd2greg functions here: https://fossies.org/linux/free42/common/core_commands7.cc (lines 207-233)
thank you! I find it amazing that so much can be done in so little ROM space. I agree it is not that hard, but it is impressive anyway.
RE: HP 12C Date calculations - Csaba Tizedes - 04-28-2019 01:35 PM
(04-24-2019 03:50 PM)detron Wrote: how the HP 12C does date calculations?
In the Manual on Page 187 maybe?!
Or you want to know it in machine code level?
Csaba