Commodore VIC-20 User Manual page 396

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The VIC 20 User Guide
Example:
?TAN(3.2)
XY(1)=TAN(180*_/180)
TI, TI$
Displays 0.0584738547
TI and TI$ represent two system time variables.
Format:
TI Number of jiffies since current startup
TI$ Time of day string
Example:
?TI
TIf"'1081000"
USR
USR is a system function that passes a parameter to a user-written
assembly language subroutine whose address is contained in memory loca-
tions I and 2. USR also fetches a return parameter from the subroutine.
Format:
USR(arg)
VAL
V AL returns the numeric equivalent of the string argument.
Format:
VAL(data$)
The number returned by VAL may be used in arithmetic computations.
V AL converts the string argument by first discarding any leading
blanks. If the first nonblank character is not a numeric digit (0-9), the
argument is returned as a value of
o.
If the first non blank is a digit, VAL
begins converting the string into real number format. If it subsequently
encounters a nondigit character, it stops processing so that the argument