add project03 base files

03/b/RAM512.hdl

@@ -0,0 +1,17 @@
+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: projects/3/b/RAM512.hdl
+/**
+ * Memory of 512 16-bit registers.
+ * If load is asserted, the value of the register selected by
+ * address is set to in; Otherwise, the value does not change.
+ * The value of the selected register is emitted by out.
+ */
+CHIP RAM512 {
+    IN in[16], load, address[9];
+    OUT out[16];
+
+    PARTS:
+    //// Replace this comment with your code.
+}