From: Nate Eldredge Newsgroups: comp.os.msdos.djgpp Subject: Re: Is there any point in MMX? Date: 12 Jan 2000 01:08:42 -0800 Organization: InterWorld Communications Lines: 25 Message-ID: <83d7r7y7vp.fsf@mercury.st.hmc.edu> References: <8599nt$1uo3r$1 AT reader2 DOT wxs DOT nl> NNTP-Posting-Host: mercury.st.hmc.edu X-Trace: nntp1.interworld.net 947668081 54024 134.173.45.219 (12 Jan 2000 09:08:01 GMT) X-Complaints-To: usenet AT nntp1 DOT interworld DOT net NNTP-Posting-Date: 12 Jan 2000 09:08:01 GMT X-Newsreader: Gnus v5.7/Emacs 20.4 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Reply-To: djgpp AT delorie DOT com "Bas Hamstra" writes: > Thanks for the answers about Win & RSXNT. I can report it works fine so far. > > About MMX: why does one hear so little about it? Could there be any > speedgain for my chess app using MMX? Aren't there a couple of extra > registers, which the x86 needs so badly? As I understand it, no. There aren't extra registers. They overload the floating-point registers into "vector" registers, and add some vector arithmetic. This means you could parallelize some of your arithmetic (i.e. do two or four or eight additions with one instruction). But you'll probably have to do it in assembly; it's a difficult thing for a compiler to handle, and GCC currently doesn't (though I believe there are some special patches). The other aspect of MMX is that MMX chips tend to come with more cache than their non-MMX counterparts. Clever strategy for Intel; MMX makes things faster right away! Who cares that the instructions are mostly useless? -- Nate Eldredge neldredge AT hmc DOT edu