Implement multi-way gates: Or8Way, Mux4Way16, Mux8Way16, DMux4Way, DMux8Way

01/DMux4Way.hdl

@@ -14,5 +14,8 @@ CHIP DMux4Way {
     OUT a, b, c, d;
 
     PARTS:
-    //// Replace this comment with your code.
+    // Use two levels of DMux: first level splits by sel[1], second level splits by sel[0]
-}
+    DMux(in=in, sel=sel[1], a=dmuxAB, b=dmuxCD);
+    DMux(in=dmuxAB, sel=sel[0], a=a, b=b);
+    DMux(in=dmuxCD, sel=sel[0], a=c, b=d);
+}

01/DMux8Way.hdl

@@ -18,5 +18,8 @@ CHIP DMux8Way {
     OUT a, b, c, d, e, f, g, h;
 
     PARTS:
-    //// Replace this comment with your code.
+    // Use one DMux and two DMux4Way gates: first split by sel[2], then each half by sel[0..1]
+    DMux(in=in, sel=sel[2], a=dmuxABCD, b=dmuxEFGH);
+    DMux4Way(in=dmuxABCD, sel=sel[0..1], a=a, b=b, c=c, d=d);
+    DMux4Way(in=dmuxEFGH, sel=sel[0..1], a=e, b=f, c=g, d=h);
 }

01/Mux4Way16.hdl

@@ -12,7 +12,10 @@
 CHIP Mux4Way16 {
     IN a[16], b[16], c[16], d[16], sel[2];
     OUT out[16];
-    
+
     PARTS:
-    //// Replace this comment with your code.
+    // Use two levels of Mux16: first level selects between pairs, second level selects final output
-}
+    Mux16(a=a, b=b, sel=sel[0], out=muxAB);
+    Mux16(a=c, b=d, sel=sel[0], out=muxCD);
+    Mux16(a=muxAB, b=muxCD, sel=sel[1], out=out);
+}

01/Mux8Way16.hdl

@@ -20,5 +20,8 @@ CHIP Mux8Way16 {
     OUT out[16];
 
     PARTS:
-    //// Replace this comment with your code.
+    // Use two Mux4Way16 gates and one Mux16 to select from 8 inputs
+    Mux4Way16(a=a, b=b, c=c, d=d, sel=sel[0..1], out=mux4wayABCD);
+    Mux4Way16(a=e, b=f, c=g, d=h, sel=sel[0..1], out=mux4wayEFGH);
+    Mux16(a=mux4wayABCD, b=mux4wayEFGH, sel=sel[2], out=out);
 }

01/Or8Way.hdl

@@ -3,7 +3,7 @@
 // by Nisan and Schocken, MIT Press.
 // File name: projects/1/Or8Way.hdl
 /**
- * 8-way Or gate: 
+ * 8-way Or gate:
  * out = in[0] Or in[1] Or ... Or in[7]
  */
 CHIP Or8Way {
@@ -11,5 +11,12 @@ CHIP Or8Way {
     OUT out;
 
     PARTS:
-    //// Replace this comment with your code.
+    // Chain Or gates to combine all 8 inputs
-}
+    Or(a=in[0], b=in[1], out=or01);
+    Or(a=in[2], b=in[3], out=or23);
+    Or(a=in[4], b=in[5], out=or45);
+    Or(a=in[6], b=in[7], out=or67);
+    Or(a=or01, b=or23, out=or0123);
+    Or(a=or45, b=or67, out=or4567);
+    Or(a=or0123, b=or4567, out=out);
+}