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HP 12C Date calculations
04-24-2019, 03:50 PM
Post: #1
HP 12C Date calculations
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.
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04-24-2019, 04:17 PM
Post: #2
RE: HP 12C Date calculations
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/...mmands7.cc (lines 207-233)
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04-24-2019, 04:26 PM
Post: #3
RE: HP 12C Date calculations
(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/...mmands7.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.
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04-28-2019, 01:35 PM (This post was last modified: 04-28-2019 01:36 PM by Csaba Tizedes.)
Post: #4
RE: HP 12C Date calculations
(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
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