1 files changed, 67 insertions, 0 deletions
diff --git a/js/src/tests/js1_8/extensions/dekker.js b/js/src/tests/js1_8/extensions/dekker.js
new file mode 100644
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+++ b/js/src/tests/js1_8/extensions/dekker.js
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ * Contributor: Jason Orendorff
+ */
+
+//-----------------------------------------------------------------------------
+
+var summary = "Dekker's algorithm for mutual exclusion";
+// Adapted from pseudocode in Wikipedia:
+// http://en.wikipedia.org/wiki/Dekker%27s_algorithm
+
+printStatus (summary);
+
+var N = 500;  // number of iterations
+
+// the mutex mechanism
+var f = [false, false];
+var turn = 0;
+
+// resource being protected
+var counter = 0;
+
+function worker(me) {
+  let him = 1 - me;
+
+  for (let i = 0; i < N; i++) {
+    // enter the mutex
+    f[me] = true;
+    while (f[him]) {
+      if (turn != me) {
+        f[me] = false;
+        while (turn != me)
+          ;  // busy wait
+        f[me] = true;
+      }
+    }
+
+    // critical section
+    let x = counter;
+    sleep(0.003);
+    counter = x + 1;
+
+    // leave the mutex
+    turn = him;
+    f[me] = false;
+  }
+
+  return 'ok';
+}
+
+var expect;
+var actual;
+
+if (typeof scatter == 'undefined' || typeof sleep == 'undefined') {
+  print('Test skipped. scatter or sleep not defined.');
+  expect = actual = 'Test skipped.';
+} else {
+  var results = scatter([function () { return worker(0); },
+                         function () { return worker(1); }]);
+
+  expect = "Thread status: [ok,ok], counter: " + (2 * N);
+  actual = "Thread status: [" + results + "], counter: " + counter;
+}
+
+reportCompare(expect, actual, summary);