> On Dec 4, 2018, at 8:19 PM, Stefan Kanthak <stefan.kant...@nexgo.de> wrote:
>
> "Paul Koning" <paulkon...@comcast.net> wrote:
>
>> Yes, that's a rather nasty cut & paste error I made.
>
> I suspected that.
> Replacing
> !(den & (1L<<31))
> with
> (signed short) den >= 0
> avoids this type of error: there's no need for a constant here!
>
> JFTR: of course the 1L should be just a 1, without suffix.
>
>> But if the 31 is changed to a 15, is the code correct?
>> I would think so.
>
> Almost. It's the standard algorithm, and it's correct except
> for den == 0, where the current implementation returns 0 as
> quotient or the numerator as remainder, while my fix yields an
> endless loop (as could be expected for "undefined behaviour").
I submitted a patch that just changes that one line. This file is a copy of
udivmodsi4.c so I figured I'd aim for the same logic except for the word length
changes, and the 31 instead of 15 was a missed edit for that.
The other changes could be left for later, or a handwritten assembly routine
used instead as some other targets do.
Thanks!
paul
