Performs a logical exclusion on two expressions, as a bitwise exclusion. For
comparisons managed as a boolean result (TRUE
or FALSE
), result is TRUE
if both expresions evaluate differently each other. The following table shows how result
is determined:
TRUE XOR TRUE = FALSE
TRUE XOR FALSE = TRUE
FALSE XOR TRUE = TRUE
FALSE XOR FALSE = FALSE
Generally speaking, the XOR
operator performs a bitwise comparison of the bits of
two numeric expressions and sets the corresponding bit in result according to the
previous table.
Note that ugBASIC uses the convention, very common in BASICs of the 1970s and 1980s,
of considering Boolean logic as implemented through the so-called "two's complement".
In other words, the value FALSE
is associated with a number composed of
all 0
s, in terms of bits. The value TRUE
is, instead,
associated with a number composed of all 1
s, again in terms of bits.
According to the 2's complement representation, a number composed of all ones is
always equivalent to the number -1
, regardless of how many bits the
number is composed of, while a number composed of all zeros is always equivalent to zero.
According to this convention, there is a coincidence between bitwise and logical
operations: in fact, a bitwise XOR
, applied to all the bits of the number,
will be equivalent to the logical operation. Note that the XOR
operator always evaluates
both expressions, which can include executing routine calls.
Because the logical and bitwise operators have lower precedence than other arithmetic and relational
operators, all bitwise operations must be enclosed in parentheses to ensure accurate results.
If the operands consist of a SIGNED BYTE
expression and a numeric expression, converts the
SIGNED BYTE
expression to a numeric value (-1
for TRUE
and 0 for FALSE
) and
performs a bitwise operation. So, the data type of the result is a numeric type appropriate
for the data types of both expressions.
= x OR y
IF x XOR x THEN: PRINT "never executed" : ELSE : PRINT "always executed": ENDIF
Join BASIC 10Liner Contest with ugBASIC!
An interesting competition is held at the beginning of each year: the
BASIC 10Liner Contest.
It is possible to use ugBASIC to participate in the next
"BASIC10Liner" competition, in the following categories:
XOR ↔ Xr
If you have found a problem with this keyword, if you think there is a bug or, more
simply, you would like it to be improved, open an issue for this example on GitHub.
Thank you!
open an issue
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