diff options
Diffstat (limited to 'js/src/tests/js1_8/extensions/dekker.js')
-rw-r--r-- | js/src/tests/js1_8/extensions/dekker.js | 68 |
1 files changed, 68 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 index 000000000..26d93d4fe --- /dev/null +++ b/js/src/tests/js1_8/extensions/dekker.js @@ -0,0 +1,68 @@ +// |reftest| skip +/* -*- 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); |