diff options
| -rw-r--r-- | mysql-test/r/select.result | 3 | ||||
| -rw-r--r-- | mysql-test/t/select.test | 5 | ||||
| -rw-r--r-- | strings/decimal.c | 13 |
3 files changed, 18 insertions, 3 deletions
diff --git a/mysql-test/r/select.result b/mysql-test/r/select.result index e6c590489a0..7f01d453906 100644 --- a/mysql-test/r/select.result +++ b/mysql-test/r/select.result @@ -3395,3 +3395,6 @@ a t1.b + 0 t1.c + 0 a t2.b + 0 c d 1 0 1 1 0 1 NULL 2 0 1 NULL NULL NULL NULL drop table t1,t2; +SELECT 0.9888889889 * 1.011111411911; +0.9888889889 * 1.011111411911 +0.9998769417899202067879 diff --git a/mysql-test/t/select.test b/mysql-test/t/select.test index b75d0dd8bb6..b44f682c02e 100644 --- a/mysql-test/t/select.test +++ b/mysql-test/t/select.test @@ -2901,3 +2901,8 @@ from t1 left outer join t2 on t1.a = t2.c and t2.b <> 1 where t1.b <> 1 order by t1.a; drop table t1,t2; + +# +# Bug #20569: Garbage in DECIMAL results from some mathematical functions +# +SELECT 0.9888889889 * 1.011111411911; diff --git a/strings/decimal.c b/strings/decimal.c index 8786a513945..ecd92a54cc9 100644 --- a/strings/decimal.c +++ b/strings/decimal.c @@ -170,6 +170,7 @@ static const dec1 frac_max[DIG_PER_DEC1-1]={ #define ADD(to, from1, from2, carry) /* assume carry <= 1 */ \ do \ { \ + DBUG_ASSERT((carry) <= 1); \ dec1 a=(from1)+(from2)+(carry); \ if (((carry)= a >= DIG_BASE)) /* no division here! */ \ a-=DIG_BASE; \ @@ -179,7 +180,7 @@ static const dec1 frac_max[DIG_PER_DEC1-1]={ #define ADD2(to, from1, from2, carry) \ do \ { \ - dec1 a=(from1)+(from2)+(carry); \ + dec2 a=((dec2)(from1))+(from2)+(carry); \ if (((carry)= a >= DIG_BASE)) \ a-=DIG_BASE; \ if (unlikely(a >= DIG_BASE)) \ @@ -187,7 +188,7 @@ static const dec1 frac_max[DIG_PER_DEC1-1]={ a-=DIG_BASE; \ carry++; \ } \ - (to)=a; \ + (to)=(dec1) a; \ } while(0) #define SUB(to, from1, from2, carry) /* to=from1-from2 */ \ @@ -1998,7 +1999,13 @@ int decimal_mul(decimal_t *from1, decimal_t *from2, decimal_t *to) ADD2(*buf0, *buf0, lo, carry); carry+=hi; } - for (; carry; buf0--) + if (carry) + { + if (buf0 < to->buf) + return E_DEC_OVERFLOW; + ADD2(*buf0, *buf0, 0, carry); + } + for (buf0--; carry; buf0--) { if (buf0 < to->buf) return E_DEC_OVERFLOW; |