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authorFrederick Yin <fkfd@fkfd.me>2022-08-16 11:54:23 +0800
committerFrederick Yin <fkfd@fkfd.me>2022-08-16 11:54:23 +0800
commit9542deeb483a00b6fabed7574720926ce97d7511 (patch)
tree0f2c1f72c03dd4693fd59df67544d2a4dddc5494 /projects/demo/Xor.hdl
parent9c0cb1d1c32724fc95ac9548e4f8d873d3adaccc (diff)
Projects, 01-06 completed
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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: projects/demo/Xor.hdl
+
+/**
+ * Exclusive-or gate: true if either a is true and b is false, or
+ * a is false and b is true; false otherwise.
+ * QUESTION: how can the simulator execute this program properly without
+ * HDL implementations of the underlying Not, And, and Or chip-parts?
+ * Answer: since the demo folder contains no Not.hdl, And.hdl and Or.hdl
+ * files, the simulator reverts to using their built-in implementations.
+ */
+
+CHIP Xor {
+ IN a, b;
+ OUT out;
+
+ PARTS:
+ Not (in=a, out=nota);
+ Not (in=b, out=notb);
+ And (a=a, b=notb, out=x);
+ And (a=nota, b=b, out=y);
+ Or (a=x, b=y, out=out);
+} \ No newline at end of file