June 2018 Update

Task/Four-bit-adder/Ring/four-bit-adder.ring

@@ -0,0 +1,69 @@
+###---------------------------
+# Program: 4 Bit Adder - Ring
+# Author:  Bert Mariani
+# Date:    2018-02-28
+#
+# Bit Adder: Input  A B Cin
+#            Output S   Cout
+#
+# A ^ B => axb                XOR gate
+#          axb ^ C => Sout    XOR gate
+#          axb & C => d       AND gate
+#
+# A & B => anb                AND gate
+#          anb | d => Cout     OR gate
+#
+# Call Adder for number of bit in input fields
+###-------------------------------------------
+### 4 Bits
+
+Cout     = "0"
+OutputS  = "0000"
+InputA   = "0101"
+InputB   = "1101"
+
+   See "InputA:.. "+ InputA +nl
+   See "InputB:.. "+ InputB +nl
+BitsAdd(InputA, InputB)
+   See "Sum...: "+ Cout +" "+ OutputS +nl+nl
+
+###-------------------------------------------
+### 32 Bits
+
+Cout     = "0"
+OutputS  = "00000000000000000000000000000000"
+InputA   = "01010101010101010101010101010101"
+InputB   = "11011101110111011101110111011101"
+
+   See "InputA:.. "+ InputA +nl
+   See "InputB:.. "+ InputB +nl
+BitsAdd(InputA, InputB)
+   See "Sum...: "+ Cout +" "+ OutputS +nl+nl
+
+###-------------------------------
+
+Func BitsAdd(InputA, InputB)
+	nbrBits = len(InputA)
+	
+	for i = nbrBits to 1 step -1
+	      A = InputA[i]
+	      B = InputB[i]
+	      C = Cout
+
+              S = Adder(A,B,C)
+	      OutputS[i] = "" + S
+	next
+return
+
+###------------------------
+Func Adder(A,B,C)
+
+    axb  =   A ^ B
+    Sout = axb ^ C
+    d    = axb & C
+
+    anb  =   A & B
+    Cout = anb | d    ### Cout is global
+
+return(Sout)
+###------------------------