0100 ;CLOCK.M65›0110 ;BY J. LITTLE›0120 ;(c)1988, ANTIC PUBLISHING›0130 ;›0140 ;USES RTCLOK FOR REAL-TIME CLOCK›0150 ;IN VBI. USES ADDRESS 20 TO KEEP›0160 ;COUNT OF JIFFIES AND USES 18 & 19›0170 ;FOR STORAGE OF COUNT OF MINUTES›0180 ;& SECONDS INSTEAD OF THEIR USUAL›0190 ;FUNCTIONS. USES LOCATION $CF TO›0200 ;KEEP COUNT OF HOURS. COUNTS›0210 ;JIFFIES IN $D0 AND $D1.›0220 ;›0230 ;Because this clock is intended›0240 ;for long-term applications,›0250 ;all calculations were made using›0260 ;the maximum number of decimal›0270 ;places, for the highest accuracy.›0280 ;Working from RTCLOK'S calculated›0290 ;error of .12776% (59.92334 HZ›0300 ;instead of 60 HZ), the jiffy›0310 ;counter is incremented every›0320 ;13.05 seconds (783 jiffies), for›0330 ;a calculated accuracy of›0340 ;approximately .00004%, or about›0350 ;1/4 second per week.›0360 ;›0370 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;›0380 ;›0390     *=  $0680›0400 ;›0410 ;SET UP VBI›0420     PLA ›0430     LDX # >START›0440     LDY # <START›0450     LDA #7›0460     JSR $E45C›0470     RTS ›0480 ;›0490 ;FIRST PART OF CODE MAKES UP›0500 ;FOR LOST TIME›0510 ;›0520 START›0530     INC $D0›0540     BNE AA›0550 ;›0560     INC $D1›0570 AA›0580     LDA $D0     ;WHEN $D0=15›0590     CMP #15     ;AND $D1=3,›0600     BCC RESUME  ;ELAPSED TIME›0610 ;›0620     LDA $D1     ;=13.05 SEC›0630     CMP #3›0640     BCC RESUME›0650 ;›0660     LDA #0      ;CLEAR COUNTERS›0670     STA $D0›0680     STA $D1›0690     LDA 20      ;IF # OF JIFFIES›0700     CMP #60     ;=60,INCREASE›0710     BCC BB      ;TO 1 INSTEAD›0720 ;›0730     LDA #1      ;OF 0 AND INC›0740     STA 20      ;SECOND COUNT.›0750     BNE CC›0760 ;›0770 BB›0780     INC 20›0790 ;›0800 ;REST OF CODE COUNTS JIFFIES,›0810 ;SECONDS, MINUTES, AND HOURS.›0820 ;›0830 RESUME›0840     LDA 20      ;COUNT JIFFIES›0850     CMP #60     ;FOR 1 SECOND›0860     BCC END›0870 ;›0880     LDA #0      ;ZERO JIFFIE›0890     STA 20      ;COUNTER THEN›0900 CC›0910     INC 19      ;UPDATE SECONDS›0920     LDA 19›0930     CMP #60›0940     BCC END     ;FOR 1 MINUTE›0950 ;›0960     LDA #0›0970     STA 19›0980     INC 18›0990     LDA 18      ;COUNT MINUTES›1000     CMP #60     ;FOR 1 HOUR›1010     BCC END›1020 ;›1030     LDA #0›1040     STA 18›1050     INC $CF     ;STORE HOUR›1060     LDA $CF     ;COUNT IN $CF›1070     CMP #24›1080     BCC END›1090 ;›1100     LDA #0›1110     STA $CF›1120 END›1130     JMP $E462›