Initial data commit

Task/Four-bit-adder/Sidef/four-bit-adder.sidef

@@ -0,0 +1,31 @@
+func bxor(a, b) {
+  (~a & b) | (a & ~b)
+}
+
+func half_adder(a, b) {
+  return (bxor(a, b), a & b)
+}
+
+func full_adder(a, b, c) {
+  var (s1, c1) = half_adder(a, c)
+  var (s2, c2) = half_adder(s1, b)
+  return (s2, c1 | c2)
+}
+
+func four_bit_adder(a, b) {
+  var (s0, c0) = full_adder(a[0], b[0], 0)
+  var (s1, c1) = full_adder(a[1], b[1], c0)
+  var (s2, c2) = full_adder(a[2], b[2], c1)
+  var (s3, c3) = full_adder(a[3], b[3], c2)
+  return ([s3,s2,s1,s0].join, c3.to_s)
+}
+
+say " A    B      A      B   C    S  sum"
+for a in ^16 {
+  for b in ^16 {
+    var(abin, bbin) = [a,b].map{|n| "%04b"%n->chars.reverse.map{.to_i} }...
+    var(s, c) = four_bit_adder(abin, bbin)
+    printf("%2d + %2d = %s + %s = %s %s = %2d\n",
+        a, b, abin.join, bbin.join, c, s, "#{c}#{s}".bin)
+    }
+}