Bug #27984 Long Decimal Maths produces truncated results.

decimal_round failed to perform a correct rounding 
of a decimal number if its first nine digits were '9'.
It just sets those digits to 0.

1 files changed, 2 insertions, 1 deletions

diff --git a/strings/decimal.c b/strings/decimal.c
index 1ae75167794..f1f02f3a071 100644
--- a/strings/decimal.c
+++ b/strings/decimal.c
@@ -1517,9 +1517,10 @@ decimal_round(decimal_t *from, decimal_t *to, int scale,
     dec1 *p0= buf0+intg0+max(frac1, frac0);
     dec1 *p1= buf1+intg1+max(frac1, frac0);
 
-    to->buf[0]= 0;
     while (buf0 < p0)
       *(--p1) = *(--p0);
+    if (unlikely(intg1 > intg0))
+      to->buf[0]= 0;
 
     intg0= intg1;
     buf0=to->buf;