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44121a6bc9
k_mul(): This didn't allocate enough result space when one input had more than twice as many bits as the other. This was partly hidden by that x_mul() didn't normalize its result. The Karatsuba recurrence is pretty much hosed if the inputs aren't roughly the same size. If one has at least twice as many bits as the other, we get a degenerate case where the "high half" of the smaller input is 0. Added a special case for that, for speed, but despite that it helped, this can still be much slower than the "grade school" method. It seems to take a really wild imbalance to trigger that; e.g., a 2**22-bit input times a 1000-bit input on my box runs about twice as slow under k_mul than under x_mul. This still needs to be addressed. I'm also not sure that allocating a->ob_size + b->ob_size digits is enough, given that this is computing k = (ah+al)*(bh+bl) instead of k = (ah-al)*(bl-bh); i.e., it's certainly enough for the final result, but it's vaguely possible that adding in the "artificially" large k may overflow that temporarily. If so, an assert will trigger in the debug build, but we'll probably compute the right result anyway(!). |
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| .. | ||
| .cvsignore | ||
| abstract.c | ||
| boolobject.c | ||
| bufferobject.c | ||
| cellobject.c | ||
| classobject.c | ||
| cobject.c | ||
| complexobject.c | ||
| descrobject.c | ||
| dictobject.c | ||
| enumobject.c | ||
| fileobject.c | ||
| floatobject.c | ||
| frameobject.c | ||
| funcobject.c | ||
| intobject.c | ||
| iterobject.c | ||
| listobject.c | ||
| listsort.txt | ||
| longobject.c | ||
| methodobject.c | ||
| moduleobject.c | ||
| object.c | ||
| obmalloc.c | ||
| rangeobject.c | ||
| sliceobject.c | ||
| stringobject.c | ||
| structseq.c | ||
| tupleobject.c | ||
| typeobject.c | ||
| unicodectype.c | ||
| unicodeobject.c | ||
| unicodetype_db.h | ||
| weakrefobject.c | ||
| xxobject.c | ||