Atari XL

72
The Atari XL Handbook
NOT. Forgetting about numerical representations
of true and false for the moment, let's look at what
these commands do.
Using AND to relate two expressions, as in the
example above, it seems fairly obvious that the
final result will be true only if both smaller
expressions are true. This is in fact what happens.
Here is a table of the possible combinations, with
the two simple expressions represented by X and Y.
This type of table is called a 'truth table'. -.
x Y
XANDY
TRUE TRUE
TRUE
TRUE FALSE
FALSE
FALSE TRUE
FALSE
FALSE FALSE
FALSE
Truth Table for AND
The command 0 R also does the obvious thing,
returning 1 if X or Y or both are true.
x
y
XORY
TRUE TRUE
TRUE
TRUE
FALSE
TRUE -
FALSE TRUE
TRUE
FALSE FALSE
FALSE
Truth Table for OR
NOT changes from true to false, and vice versa, so: