diff --git a/lib/FloatedBigDigit.js b/lib/FloatedBigDigit.js
index b6f62c9..4de75ea 100644
--- a/lib/FloatedBigDigit.js
+++ b/lib/FloatedBigDigit.js
@@ -1,7 +1,7 @@
 /* FLOATED BIG DIGIT CLASS */
 /* CREATE  2021.02.06      */
-/* REVISED 2021.05.21      */
-/* Ver 0.8.5               */
+/* REVISED 2021.05.22      */
+/* Ver 0.8.6               */
 /* Original by K-ARAI      */
 
 
@@ -2568,7 +2568,6 @@ function FloatedBigDigit() {
 
         var stop = ( C.compare(floatedBigDigit_LM2)>=0 );
 
-
         this.set(1);
         while(C.compare(1)>0) {
             this.Mul(F);
@@ -3263,8 +3262,6 @@ function FloatedBigDigit() {
 
         if(this.checkOver()) return floatedBigDigitERR;
 
-        if(stop) return floatedBigDigitERR;
-
         return floatedBigDigitOK;
 
     }
@@ -3290,6 +3287,8 @@ function FloatedBigDigit() {
             return floatedBigDigitERR;
         }
 
+        if(F.order()<-floatedBigDigit_order*4/10) return this.SetAsinhB(V);
+
         var C = new FloatedBigDigit();
         C.set(0);
         this.set(1);
@@ -3348,8 +3347,6 @@ function FloatedBigDigit() {
 
         if(this.checkOver()) return floatedBigDigitERR;
 
-        if(stop) return floatedBigDigitERR;
-
         return floatedBigDigitOK;
 
     }
@@ -3380,10 +3377,12 @@ function FloatedBigDigit() {
 
         F.Div(A);
 
-        F.add(1);
-
         B.Copy(V);
         B.minus = false;
+
+        if(F.isOver()) F.Copy(B);
+
+        F.add(1);
         F.Add(B);
 
         this.SetLn(F);
@@ -3424,6 +3423,8 @@ function FloatedBigDigit() {
             return floatedBigDigitERR;
         }
 
+        if(F.order()<-floatedBigDigit_order*4/10) return this.SetAcoshB(V);
+
         var C = new FloatedBigDigit();
         C.set(0);
         this.set(1);
@@ -3513,6 +3514,8 @@ function FloatedBigDigit() {
         B.set(2);
         A.PowerDiv(B);
 
+        if(A.isOver()) A.Copy(V);
+
         A.Add(V);
 
         this.SetLn(A);