🚀 go-pugleaf

In article <1992Aug31.151640.16824@megatek.com>, rstewart@ganglia.megatek.uucp (Rich Stewart) writes:
|> In article <Btr4Iz.GB9@pgroup.com> lfm@pgroup.com (Larry Meadows) writes:
|> >In article <1992Aug29.031847.28867@nas.nasa.gov> klee@wilbur.nas.nasa.gov (King M. Lee) writes:
|> >>
|> >>One reason why the i860(tm) did do better may be that good compilers
|> >>were not available when it was first introduced. It would have been
|> >>better for the i860 if they had developed compilers while designing
|> >>the chip. The compilers have improved, but it may be too late.
|> >
|> >Are you listening, Intel?
|> >
|> >>
|> >>Of all the modern micros, the i860(tm) is the  only one I know of
|> >>that allows one to bypass cache. There are two instructions to
|> >
|> >Yes!  Very good point.  If you can't bypass cache then you have
|> >to hope/arrange for re-use, which is much harder.
|> >-- 
|> >Larry Meadows		The Portland Group
|> >lfm@pgroup.com
|> 
|> Stop this. You can bypass cache on lots of chips. Most caching cpu's
|> can have cache bypassed in the page tables. A second way, if your board
|> is designed to do it, is a software toggle of some sort. I think, most
|> modern cpu's, have a cache enable/disable pin.

Ah, but tha i860 is the only one that allows you to do it on a load-by-load
basis, without a lot of OS and page table crufting about, and without flipping
mode bits, which was Larry's point.

|> And finally, you do not want to use pfld's that might access memory
|> that is in a cachable address range. (Right Larry?).

Nope, wrong. The pfld instruction works just fine on something which is in cache
- the main memory access gets ignored, and the value from the cache is returned.

All in all, the i860 is rather strange, but when you hit the "sweet spot", watch
out.

-- 
Kirk Hays - NRA Life.
Start your day with a little civil disobedience.  Call BATF at 1-800-ATF-GUNS or
1-800-RUN-GUNS, tell them what you think of gun grabbers and government employees
that encourage people to narc on their neighbors.  Good for the soul.