diff --git a/random/mersennetwister.js b/random/mersennetwister.js
index 6af13ae..21257f1 100644
--- a/random/mersennetwister.js
+++ b/random/mersennetwister.js
@@ -1,64 +1,20 @@
-// this program is a JavaScript version of Mersenne Twister, with concealment and encapsulation in class,
-// an almost straight conversion from the original program, mt19937ar.c,
-// translated by y. okada on July 17, 2006.
-
-// Changes by Jesse Ruderman:
-//   * Use intish/int32 rather than uint32 for intermediate calculations
-//     (see https://bugzilla.mozilla.org/show_bug.cgi?id=883748#c1)
-//   * Added functions for exporting/importing the entire PRNG state
-//   * Removed parts not needed for fuzzing
-
-// in this program, procedure descriptions and comments of original source code were not removed.
-// lines commented with //c// were originally descriptions of c procedure. and a few following lines are appropriate JavaScript descriptions.
-// lines commented with /* and */ are original comments.
-// lines commented with // are additional comments in this JavaScript version.
-// before using this version, create at least one instance of MersenneTwister19937 class, and initialize the each state, given below in c comments, of all the instances.
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /*
-   A C-program for MT19937, with initialization improved 2002/1/26.
-   Coded by Takuji Nishimura and Makoto Matsumoto.
+ * JavaScript version of Mersenne Twister
+ *
+ * @author Yasuharu Okada
+ *
+ */
 
-   Copyright (C) 1997 - 2002, Makoto Matsumoto and Takuji Nishimura,
-   All rights reserved.
-
-   Redistribution and use in source and binary forms, with or without
-   modification, are permitted provided that the following conditions
-   are met:
-
-     1. Redistributions of source code must retain the above copyright
-        notice, this list of conditions and the following disclaimer.
-
-     2. Redistributions in binary form must reproduce the above copyright
-        notice, this list of conditions and the following disclaimer in the
-        documentation and/or other materials provided with the distribution.
-
-     3. The names of its contributors may not be used to endorse or promote
-        products derived from this software without specific prior written
-        permission.
-
-   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
-   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
-   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
-   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-
-   Any feedback is very welcome.
-   http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html
-   email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space)
-*/
-
-
-function MersenneTwister19937()
+function MersenneTwister()
 {
   const N = 624;
   const M = 397;
+  const UPPER_MASK = 0x80000000;
+  const LOWER_MASK = 0x7fffffff;
   const MAG01 = new Int32Array([0, 0x9908b0df]);
 
   var mt = new Int32Array(N);   /* the array for the state vector */
@@ -66,38 +22,50 @@ function MersenneTwister19937()
 
   this.seed = function (s) {
     mt[0] = s | 0;
-    for (mti=1; mti<N; mti++) {
-      mt[mti] = Math.imul(1812433253, mt[mti-1] ^ (mt[mti-1] >>> 30)) + mti;
+    for (mti = 1; mti < N; mti++) {
+      mt[mti] = Math.imul(1812433253, mt[mti - 1] ^ (mt[mti - 1] >>> 30)) + mti;
     }
   };
 
-  this.export_state = function() { return [mt, mti]; };
-  this.import_state = function(s) { mt = s[0]; mti = s[1]; };
-  this.export_mta = function() { return mt; };
-  this.import_mta = function(_mta) { mt = _mta; };
-  this.export_mti = function() { return mti; };
-  this.import_mti = function(_mti) { mti = _mti; };
+  this.export_state = function() {
+    return [mt, mti];
+  };
 
-  function mag01(y)
-  {
-    return MAG01[y & 0x1];
-  }
+  this.import_state = function(s) {
+    mt = s[0];
+    mti = s[1];
+  };
+
+  this.export_mta = function() {
+    return mt;
+  };
+
+  this.import_mta = function(_mta) {
+    mt = _mta;
+  };
+
+  this.export_mti = function() {
+    return mti;
+  };
+
+  this.import_mti = function(_mti) {
+    mti = _mti;
+  };
 
   this.int32 = function () {
-    var y;
-    var kk;
+    var y, kk;
 
     if (mti >= N) { /* generate N words at one time */
-      for (kk=0;kk<N-M;kk++) {
-        y = ((mt[kk]&0x80000000)|(mt[kk+1]&0x7fffffff));
-        mt[kk] = (mt[kk+M] ^ (y >>> 1) ^ mag01(y));
+      for (kk = 0; kk < N-M; kk++) {
+        y = ((mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK));
+        mt[kk] = (mt[kk+M] ^ (y >>> 1) ^ MAG01[y & 0x1]);
       }
-      for (;kk<N-1;kk++) {
-        y = ((mt[kk]&0x80000000)|(mt[kk+1]&0x7fffffff));
-        mt[kk] = (mt[kk+(M-N)] ^ (y >>> 1) ^ mag01(y));
+      for (; kk < N-1; kk++) {
+        y = ((mt[kk] & UPPER_MASK) | (mt[kk+1] & LOWER_MASK));
+        mt[kk] = (mt[kk+(M-N)] ^ (y >>> 1) ^ MAG01[y & 0x1]);
       }
-      y = ((mt[N-1]&0x80000000)|(mt[0]&0x7fffffff));
-      mt[N-1] = (mt[M-1] ^ (y >>> 1) ^ mag01(y));
+      y = ((mt[N-1] & UPPER_MASK) | (mt[0] & LOWER_MASK));
+      mt[N-1] = (mt[M-1] ^ (y >>> 1) ^ MAG01[y & 0x1]);
       mti = 0;
     }
 
@@ -111,4 +79,8 @@ function MersenneTwister19937()
 
     return y;
   };
+
+  this.genrand_real2 = function () {
+    return this.genrand_int32() * (1.0 / 4294967296.0);
+  }
 }