diff --git a/lib/bn.js b/lib/bn.js
index fe5c726..33f7c24 100644
--- a/lib/bn.js
+++ b/lib/bn.js
@@ -327,6 +327,13 @@
     dest.red = this.red;
   };
 
+  BN.prototype.move = function move (dest) {
+    dest.words = this.words;
+    dest.length = this.length;
+    dest.negative = this.negative;
+    dest.red = this.red;
+  };
+
   BN.prototype.clone = function clone () {
     var r = new BN(null);
     this.copy(r);
@@ -3170,8 +3177,7 @@
   Red.prototype.imod = function imod (a) {
     if (this.prime) return this.prime.ireduce(a)._forceRed(this);
 
-    var mod = a.umod(this.m)._forceRed(this);
-    if (mod !== a) mod.copy(a);
+    a.umod(this.m)._forceRed(this).move(a);
     return a;
   };