diff options
| -rw-r--r-- | Objects/longobject.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/Objects/longobject.c b/Objects/longobject.c index ee20e26..5f0cc57 100644 --- a/Objects/longobject.c +++ b/Objects/longobject.c @@ -2767,8 +2767,15 @@ x_divrem(PyLongObject *v1, PyLongObject *w1, PyLongObject **prem) vtop = vk[size_w]; assert(vtop <= wm1); vv = ((twodigits)vtop << PyLong_SHIFT) | vk[size_w-1]; + /* The code used to compute the remainder via + * r = (digit)(vv - (twodigits)wm1 * q); + * and compilers generally generated code to do the * and -. + * But modern processors generally compute q and r with a single + * instruction, and modern optimizing compilers exploit that if we + * _don't_ try to optimize it. + */ q = (digit)(vv / wm1); - r = (digit)(vv - (twodigits)wm1 * q); /* r = vv % wm1 */ + r = (digit)(vv % wm1); while ((twodigits)wm2 * q > (((twodigits)r << PyLong_SHIFT) | vk[size_w-2])) { --q; |