diff options
| -rw-r--r-- | Objects/longobject.c | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index 0801e64..0f4910e 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -1663,7 +1663,7 @@ k_mul(PyLongObject *a, PyLongObject *b) */ /* 1. Allocate result space. */ - ret = _PyLong_New(asize + bsize); + ret = _PyLong_New(asize + bsize + 1); if (ret == NULL) goto fail; #ifdef Py_DEBUG /* Fill with trash, to catch reference to uninitialized digits. */ @@ -1727,7 +1727,15 @@ k_mul(PyLongObject *a, PyLongObject *b) Py_DECREF(t2); if (t3 == NULL) goto fail; - /* Add t3. */ + /* Add t3. Caution: t3 can spill one bit beyond the allocated + * result space; it's t3-al*bl-ah*bh that always fits. We have + * to arrange to ignore the hight bit. + */ + if (t3->ob_size > i) { + assert(t3->ob_size == i+1); /* just one digit over */ + assert(t3->ob_digit[t3->ob_size - 1] == 1); /* & just one bit */ + --t3->ob_size; /* ignore the overflow bit */ + } (void)v_iadd(ret->ob_digit + shift, i, t3->ob_digit, t3->ob_size); Py_DECREF(t3); @@ -1761,7 +1769,7 @@ long_mul(PyLongObject *v, PyLongObject *w) return Py_NotImplemented; } -#if 0 +#if 1 if (Py_GETENV("KARAT") != NULL) z = k_mul(a, b); else |