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ANSI Common Lisp  12 Numbers 12.2 Dictionary of Numbers
- Syntax:
-
logbitp
index integer
 generalized-boolean
- Arguments and Values:
-
index - a non-negative integer.
integer - an integer.
generalized-boolean - a generalized boolean.
- Description:
-
logbitp is used to test the value of a particular bit
in integer, that is treated as if it were binary.
The value of logbitp is true if the bit in integer
whose index is index (that is, its weight is 2index)
is a one-bit; otherwise it is false.
Negative integers are treated as if they were in
two's-complement notation.
- Examples:
-
(logbitp 1 1) false
(logbitp 0 1) true
(logbitp 3 10) true
(logbitp 1000000 -1) true
(logbitp 2 6) true
(logbitp 0 6) false
- Exceptional Situations:
-
Should signal an error of type type-error if index is not a non-negative integer.
Should signal an error of type type-error if integer is not an integer.
- Notes:
-
(logbitp k n) ==(ldb-test (byte 1 k) n)
- Allegro CL Implementation Details:
-
None.
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