Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!think.com!hsdndev!cmcl2!kramden.acf.nyu.edu!brnstnd
From: brnstnd@kramden.acf.nyu.edu (Dan Bernstein)
Newsgroups: comp.arch
Subject: Re: Unusual instructions and constructions
Message-ID: <22782:Mar1502:10:3291@kramden.acf.nyu.edu>
Date: 15 Mar 91 02:10:32 GMT
References: <7499@mentor.cc.purdue.edu> <2378@tuvie.UUCP>
Organization: IR
Lines: 20

In article <2378@tuvie.UUCP> alex@vmars.tuwien.ac.at (Alexander Vrchoticky) writes:
> hrubin@pop.stat.purdue.edu (Herman Rubin) writes:
> > Even the addition of two vectors to
> > produce a result should have different C code on different machines.
> For the purposes of design diversity? Are you sure you did not want to
> type `machine' instead of `C' there?

#ifdef VECTOR
   for (i = 0; i < k; i++) y[i] = neg(x[i + r - k]);
   for (i = k; i < r; i++) y[i] = x[i - k];
   for (i = 0; i < r; i++) x[i] = y[i];
#else
   for (i = 0; i < k; i++) y[i] = x[i + r - k];
   for (i = r - 1; i >= k; i--) x[i] = x[i - k];
   for (i = 0; i < k; i++) x[i] = neg(y[i]);
#endif

Well, okay, this is negacyclic rotation, but the point is the same.

---Dan