From 9542deeb483a00b6fabed7574720926ce97d7511 Mon Sep 17 00:00:00 2001
From: Frederick Yin <fkfd@fkfd.me>
Date: Tue, 16 Aug 2022 11:54:23 +0800
Subject: Projects, 01-06 completed

---
 projects/03/a/PC.hdl | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 projects/03/a/PC.hdl

(limited to 'projects/03/a/PC.hdl')

diff --git a/projects/03/a/PC.hdl b/projects/03/a/PC.hdl
new file mode 100644
index 0000000..0e44698
--- /dev/null
+++ b/projects/03/a/PC.hdl
@@ -0,0 +1,24 @@
+// 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/03/a/PC.hdl
+
+/**
+ * A 16-bit counter with load and reset control bits.
+ * if      (reset[t] == 1) out[t+1] = 0
+ * else if (load[t] == 1)  out[t+1] = in[t]
+ * else if (inc[t] == 1)   out[t+1] = out[t] + 1  (integer addition)
+ * else                    out[t+1] = out[t]
+ */
+
+CHIP PC {
+    IN in[16],load,inc,reset;
+    OUT out[16];
+
+    PARTS:
+	Register(in=fb, load=true, out=reg, out=out);
+	Inc16(in=reg, out=reg1);
+	Mux16(a=reg, b=reg1, sel=inc, out=cnt);
+	Mux16(a=cnt, b=in, sel=load, out=cntin);
+	Mux16(a=cntin, b=false, sel=reset, out=fb);
+}
-- 
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