Greetings! Matthew Wilcox <[EMAIL PROTECTED]> writes:
> On Wed, Jun 09, 2004 at 01:42:38PM -0400, Camm Maguire wrote: > > :-) Indeed. Yes I was not proposing an endeavor to create such a > > facility, just to package one that might already exist, in this case > > certainly through a flag passed to gcc. > > That was what I assumed. I don't think there is such a flag at this point. > > > Most of the subarchitecture > > builds can only substantively benefit from isa extensions that 1) > > implement memory prefetch and 2) vectorize floating point > > operations. > > We do have memory prefetch instructions on PA2.0 processors, but (again, > from the conversation at GCC Summit), GCC hasn't been taught about > them yet. This should be considerably easier to do than the half-word > saturated arithmetic stuff. > Atlas has a well developed facility for using C macros to call various flavors of prefetch via __asm__ statements. This is at least used in this manner on i386 and powerpc, on which gcc also does not emit such instructions. Not that this warrants any immediate work, but my understanding is that some speedup of l1 and l2 in particular could be had with minimal labor. Am ccing atlas upstream on this. Take care, > As far as vectorized floating point, PA doesn't have it. The designers > seem to have considered vectorized fixed-point / integer arithmetic as > more important. > > -- > "Next the statesmen will invent cheap lies, putting the blame upon > the nation that is attacked, and every man will be glad of those > conscience-soothing falsities, and will diligently study them, and refuse > to examine any refutations of them; and thus he will by and by convince > himself that the war is just, and will thank God for the better sleep > he enjoys after this process of grotesque self-deception." -- Mark Twain > > > -- Camm Maguire [EMAIL PROTECTED] ========================================================================== "The earth is but one country, and mankind its citizens." -- Baha'u'llah
