Wow, that "Astronomical Formulae for Calculator" by Jean Meeus looks heavy. Too heavy. I want something simple for date/time calculations:
a) to subtract two dates to get the number of days
b) to add n days to a date; e.g. Jul 4 2004 + 207 days =
c) to convert hh:mm:ss into 0.xxxx; e.g. noon = 0.5

And not to put myself down, but I was sort of hoping I would not have my own program doing that logic (this is my 1st year as an 8051 assembler programmer -- though I've programmed in 360 Assembler and in SAS). I was hoping that all the logic would be done in a nice, self-contained 8051 assembler language subroutine by someone who has used the code and has debugged it over the years.