Commodore VIC-20 - Page 81

binary code called "ASCII." The Appendix lists the ASCII code
assigned to every VIC character.
EXAMPLES:
"A"<"B" results in true (-1)
"X" = "XX" results in false (0)
C$ S
The Boolean operators AND, OR, and NOT specify a Boolean
logic operation to be performed on two variables, on adjacent sides
of the operator. In the case of NOT, only the term to the right is
considered. Boolean operations are not performed until all
anthmetic and relational operations have been completed.
EXAMPLES:
IF A- 100 AND B = 100 THEN 10
If both A and B are equal to 100, branch to
statement 10.
IF X<Y AND B> = 44 THEN F = 0
If X is less than Y, and B is greater than
or equal to 44, then set F equal to 0.
IF A = 100 or B = 100 THEN 20
If either A or B has a value of 100, branch to
statement 20.
IF X<Y OR B> = 44 THEN F = 0
F is set to 0 if X is less than Y, or B is greater
than 43.
Asingle term being tested for "true" or "false" can be specified by
the term itself, with an implied "<>0" following it. Any non-zero
value is considered true; a zero value is considered false.
EXAMPLES:
IF A THEN B = 2
IF A<>0 THEN B = 2
The above two statements are equivalent.
IF NOT B THEN 100
Branch if B is false, i.e., equal to zero. This is
probably better written as:
IFB = 0THEN 100
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