= x AND y
Performs a logical conjunction on two expressions, as a bitwise conjunction. For comparisons managed
as a boolean result (TRUE
or FALSE
), result is TRUE
if, and
only if, both expresions evaluate to TRUE
. The following table shows how result is determined:
'TRUE AND TRUE = TRUE
'
'TRUE AND FALSE = FALSE
'
'FALSE AND TRUE = FALSE
'
'FALSE AND FALSE = FALSE
'
Generally speaking, the AND
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 AND
, applied to all the bits of the number,
will be equivalent to the logical operation. Note tha the AND
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.
IF x AND 1 THEN PRINT "x is odd" ELSE PRINT "x is even" ENDIF
An
If you have encountered a problem using this command, if you think there is a bug or the explanation is unclear, please open an issue for this keyword on GitHub. Thank you!