On Thursday 08 July 2010 08:26:02 Fredrik Johansson wrote: > On Wed, Jul 7, 2010 at 11:36 PM, Jason Moxham <ja...@njkfrudils.plus.com>wrote: > > On Tuesday 06 July 2010 10:49:35 Bill Hart wrote: > > > Frederick is working on mpz_mulhi, however one thing we *really* need > > > (since the interesting case for his applications is for a small number > > > of limbs) is an x86_64 assembly version for the basecase, as at > > > present I think we just use a full multiplication. I think this should > > > save a large percentage of the time (nearly half I think). > > > > > > Jason, do you by any chance have any code for this? > > > > I can easily write one , which one do we want though > > ie size n * size n to top n digits or the general xn* yn to zn or some > > inbetween one? > > Hi Jason, that would be awesome. > > The general case is probably necessary. More specifically, the application > is to multiply fixed-point numbers x, y, which don't have to be the same > size, discarding a fixed number of the lower limbs (i.e.computing an > approximation of floor(x*y / 2^(n*GMP_LIMB_BITS)) for integers x and y of > arbitrary length). > > Fredrik
The mulhi and mullo are exact unlike the mulmid , we could do an approximate mulhi which would be marginally faster. Jason -- You received this message because you are subscribed to the Google Groups "mpir-devel" group. To post to this group, send email to mpir-de...@googlegroups.com. To unsubscribe from this group, send email to mpir-devel+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/mpir-devel?hl=en.
