Commodore VIC-20 - Page 162

148 The VIC 20 User Guide
and TI; they are numbers representing real time, calculated from jiffy time
(TIME, TI). The conversion
is done as follows: Each second is divided into
60 jiffies. One minute is composed of 60 seconds. One hour is made up of 60
minutes. Thus, one second is 60 jiffies, one minute is 3600 jiffies, and one
hour
is 216,000 jiffies, as illustrated.
Jiffy
Minute
= 1
~ Second/60 = Jiffy
= 60 X Jiffy
= 60 Jiffies
~ 60 X S""ond ~
L- ___ ~_~~_O_~_}_~f_~i_~_~ff_ie_S_) --.JI- Minu~o = Second /60 = Jiffy
Hour
= 60 X Minute ~
= 60 X (3600 Jiffies) I- Hour/60 = Minute/60 = Second/60 = Jiffy
= 216,000 Jiffies
The following program converts jiffy time (J) into real time, shown as
hours (H), minutes (M), and seconds (S). A complete program follows the
statement descriptions.
19 J=TI Calculate hours. Integer function
20 H=INT(J/216000) takes only whole number.
39 IF H00 THEN J=J-H*216009 If any hours, subtract number of
jiffies in one hour by H to leave
remaining jiffies.
40
M= I NT< .TI3600) Calculate minutes.
Integer function takes only whole
number.
50 IF
MOe THEN J=J-M!lE3600 If any minutes, subtract number of
jiffies in minutes by 7 to leave
remaining jiffies.
60 S=INT<J/6fl) Calculate seconds. Integer function
takes only whole number.