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+// This file is part of www.nand2tetris.org
+// and the book "The Elements of Computing Systems"
+// by Nisan and Schocken, MIT Press.
+// File name: tools/builtIn/RAM4K.hdl
+
+/**
+ * Memory of 4K registers, each 16-bit wide.  
+ * The chip facilitates read and write operations, as follows:
+ *     Read:  out(t) = RAM4K[address(t)](t)
+ *     Write: If load(t-1) then RAM4K[address(t-1)](t) = in(t-1)
+ * In words: the chip always outputs the value stored at the memory 
+ * location specified by address. If load == 1, the in value is loaded 
+ * into the memory location specified by address.  This value becomes 
+ * available through the out output starting from the next time step.
+ */
+
+CHIP RAM4K {
+
+    IN  in[16], load, address[12];
+    OUT out[16];
+
+    BUILTIN RAM4K;
+    CLOCKED in, load;
+}