From fd0b6ef3fb566996121971ada06b1d2ba847d8d0 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Sun, 25 Dec 2016 08:47:22 +0000
Subject: bignum.c: precise fdiv

* bignum.c (big_fdiv): more precise calculation.  [ruby-dev:49915]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57179 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 bignum.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/bignum.c b/bignum.c
index 41b1043b99..bc283ac89a 100644
--- a/bignum.c
+++ b/bignum.c
@@ -6102,6 +6102,8 @@ big_fdiv(VALUE x, VALUE y, long ey)
     l = BIGNUM_LEN(x);
     ex = l * BITSPERDIG - nlz(BDIGITS(x)[l-1]);
     ex -= 2 * DBL_BIGDIG * BITSPERDIG;
+    if (ex > BITSPERDIG) ex -= BITSPERDIG;
+    else if (ex > 0) ex = 0;
     if (ex) x = big_shift(x, ex);
 
     bigdivrem(x, y, &z, 0);
-- 
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