Hello Kurt:
"It pulls the Year, Month and Day values from the clock chip but then does it's own calculations. This makes leap days valid." As I recall, the clock chip does not express February 29 on leap days because it does not incorporate leap years within its date algorithm. So when a leap year arrives and time passes 23:59:00 on February 28, the clock chip advances to time of 00:00:00 and date of March 1. But it is possible to incorporate a Modified Julian Date algorithm into a program that will be accurate. One is part of the Sun Compass program, which can be found at the Club 100 website as first place entry of the Club 100 27th annual programming contest. Keeper of the Primordial Bit (mother of all bits), -= Ron Wiesen =- _____ From: M100 [mailto:m100-boun...@lists.bitchin100.com] On Behalf Of Kurt McCullum Sent: Monday, June 29, 2015 20:20 To: Model 100 Discussion Subject: [M100] Time Minder I recently acquired (Thanks Lee!) a copy of Time Minder for the T200. After loading it up I realized that it suffered from a Y2K bug. Different from what we see on Menu which is just a fixed value. Time Minder calculates all dates from an epoch of Jan 1 1900 and ignores the DAY$ value in the clock. So when calculating calendar, there was no way to make it work on dates above December 31st, 1999. It pulls the Year, Month and Day values from the clock chip but then does it's own calculations. This makes leap days valid. But trying to build a calendar for 2015 results in a 1915 calendar. After some digging with Virtual-T, I replaced a LDA command with a CALL to 6 new bytes of code. There I loaded the Year and added 100 to the accumulator. This makes all the calendars appear perfectly on dates past 2000. The only problem now is displaying 20 instead of 19 on the screen. For some reason finding that code has eluded me, but the software is not functional. There are 4 version of Time Minder, two for loading from the cassette port and two from the DVI/TS-Dos. Right now I have the DVI/TS-Dos versions working but still displaying 19 instead of 20 for the century. My next step is to apply the epoch year fix to the cassette versions and then try to fix the display issue. Kurt
