RosettaCodeData/Task/Four-bit-adder/Clojure/four-bit-adder-3.clj

34 lines
1.2 KiB
Clojure

(defn to-binary-seq [^long x]
(map #(- (int %) (int \0))
(Long/toBinaryString x)))
(defn half-adder [a b]
[(bit-xor a b)
(bit-and a b)])
(defn full-adder [a b carry]
(let [added (half-adder b carry)
half-sum (first added)]
[(first (half-adder a half-sum))
(bit-or (second (half-adder a half-sum)) (second added))]))
(defn ripple-carry-adder [a b]
(loop [a (reverse a)
b (reverse b)
sum '()
carry 0]
(let [added (full-adder (first a) (first b) carry)]
(if (and (empty? (next a)) (empty? (next b)))
(conj sum (first added) (bit-or carry 1))
(recur (next a) (next b) (conj sum (first added)) (second added))))))
(deftest adder
(is (= (Long/parseLong (apply str (ripple-carry-adder (to-binary-seq 10) (to-binary-seq 10))) 2)
(+ 10 10)))
(is (= (Long/parseLong (apply str (ripple-carry-adder (to-binary-seq 50) (to-binary-seq 50))) 2)
(+ 50 50)))
(is (= (Long/parseLong (apply str (ripple-carry-adder (to-binary-seq 32) (to-binary-seq 38))) 2)
(+ 32 38)))
(is (= (Long/parseLong (apply str (ripple-carry-adder (to-binary-seq 130) (to-binary-seq 250))) 2)
(+ 130 250))))