clojure.core/unsigned-bit-shift-right

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Type: function Added: Clojure 1.6 Examples: 3 Runnable: 3

([x n])

Bitwise shift right, without sign-extension.

Examples

by jafingerhut on 2014-09-30 ▶

(format "%016x" -1) "ffffffffffffffff" ;; bit-shift-right sign extends most significant bit while right shifting. (format "%016x" (bit-shift-right -1 10)) "ffffffffffffffff" ;; unsigned-bit-shift-right fills most significant bits of result with 0. ;; No sign extension. (format "%016x" (unsigned-bit-shift-right -1 10)) "003fffffffffffff"

by fasiha on 2016-04-07 ▶

;; Warning: unsigned-bit-shift-right, like bit-shift-right, treats inputs as ;; type Long. Smaller types like byte, short, and int will not behave as such. (format "0x%x" (byte -128)) ; => "0x80" (format "0x%x" (unsigned-bit-shift-right (byte -128) 1)) ; => "0x7fffffffffffffc0" (format "0x%x" (bit-shift-right (byte -128) 1)) ; => "0xffffffffffffffc0" ; If you expected 0x40, you need to upcast your byte yourself, via bit-and, ; and only then shift: (format "0x%x" (bit-shift-right (bit-and 0xff (byte -128)) 1)) ; => "0x40"

by Sophia-Gold on 2016-12-28 ▶

;; Stein's Algorithm (Binary GCD) ;; https://en.wikipedia.org/wiki/Binary_GCD_algorithm (defn gcd [a b] (cond (zero? a) b (zero? b) a (neg? a) (- a) (neg? b) (- b) (and (even? a) (even? b)) (* 2 (gcd (unsigned-bit-shift-right a 1) (unsigned-bit-shift-right b 1))) (and (even? a) (odd? b)) (recur (unsigned-bit-shift-right a 1) b) (and (odd? a) (even? b)) (recur a (unsigned-bit-shift-right b 1)) (and (odd? a) (odd? b)) (recur (unsigned-bit-shift-right (Math/abs (long (- a b))) ;; coerce to avoid reflection 1) (min a b))))

See also

• clojure.core/bit-shift-right (4)

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