Bill Schottstaedt escreveu: >> I have removed support for the reduced bit, and put the reduction in >> make_fraction. > > I think it was intended that equal? would use scm_i_fraction_equalp > which reduces both arguments before checking equality. So the > simplest fix would be to mask off the reduced bit in the cell type > in the check for cell type equality in scm_equalp. I would hesitate > to remove support for this bit because it will mean you get gcd > on every integer divide! The current system already slows Guile
I think thes best quick fix would be to put the bit into the 4th double cell word. > down by about 10%. On the race condition, my vage recollection > is that the "is this safe?" question was mine, and I hoped at that > time that someone who knew about such things would check it > out -- I believe (it's been a long time since I looked at this stuff) > that if that line is not safe, there are a lot more like it scattered > around Guile, so it's scarcely reason to jettison the entire thing. In that case, we need to fix the more-like-it stuff. Can you point out some of those cases? I'm hesitant to put stuff like this in because 1. it _is_ a race condition 2. if it is triggered, it will be next to impossible to reproduce. In effect this would lead to a once in a million inexplicable corruption. And that's really bad. The correct solution would be a to use a lock-free instruction to swap the old and reduced forms, but I'm not sure if we have those in GUILE. As I explained earlier, the logic for doing reduces or not needs to be more refined. Any program that does serious arithmetic in fractions will likely have exploding memory requirements. -- Han-Wen Nienhuys - [EMAIL PROTECTED] - http://www.xs4all.nl/~hanwen _______________________________________________ Guile-devel mailing list [email protected] http://lists.gnu.org/mailman/listinfo/guile-devel
