2 files changed, 7 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index 5d0da3e420..930b5ebe96 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Aug  1 01:45:18 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (big2str_karatsuba): Fix a condition of power_level.
+
 Thu Aug  1 01:09:02 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (LOG2_KARATSUBA_BIG2STR_DIGITS): Removed.
diff --git a/bignum.c b/bignum.c
index cd3f6d3f44..5e6c337723 100644
--- a/bignum.c
+++ b/bignum.c
@@ -4225,6 +4225,8 @@ big2str_orig(struct big2str_struct *b2s, VALUE x, char* ptr, size_t len, int tri
     size_t j = len;
     BDIGIT* ds = BDIGITS(x);
 
+    assert(i <= 2);
+
     while (i && j > 0) {
 	long k = i;
 	BDIGIT_DBL num = 0;
@@ -4266,7 +4268,7 @@ big2str_karatsuba(struct big2str_struct *b2s, VALUE x, char* ptr,
 	}
     }
 
-    if (power_level == 0) {
+    if (power_level < 0) {
 	return big2str_orig(b2s, x, ptr, len, trim);
     }