diff options
| author | Yuchen Pei <me@ypei.me> | 2017-11-29 12:30:41 +0100 |
|---|---|---|
| committer | Yuchen Pei <me@ypei.me> | 2017-11-29 12:30:41 +0100 |
| commit | a000308104aab27c2dde9a306f1bc654b2db4806 (patch) | |
| tree | aecc628e14c1628b5714281437aba18680cdc27b /projects/demo/Xor.hdl | |
first commit
Diffstat (limited to 'projects/demo/Xor.hdl')
| -rw-r--r-- | projects/demo/Xor.hdl | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/projects/demo/Xor.hdl b/projects/demo/Xor.hdl new file mode 100644 index 0000000..db49351 --- /dev/null +++ b/projects/demo/Xor.hdl @@ -0,0 +1,25 @@ +// 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 |