Re: MATH_EMULATE

[Heikki Suonsivu <hsu%hsu.bbnetworks.net@localhost>]

My two pennies worth:

Non-FPU seems to be coming back, whether we want it or not.  It is not
just old obsolete computers.  In addition to embedded stuff, there are
things like tiny low-power consumption PCs as well coming from Taiwan
and China.  The one I just got is a new version of eBOX 2300, the eBOX
2300SX (www.compactpc.com.tw, this is sold under other brand names as
well), which has 300+MHz 486, includes CF slot, mini-pci slot, couple
of serial ports, 10/100 ethernet, VGA, 128M, 3*USB2, audio.  The thing
fits on your palm.  It takes 0.6A of 5V, that is about 3W for the
computer (assuming you use a CF card for mass memory and not 2.5" hard
disk), so it runs a week on a car battery.  Because of Mini-PCI
option, it also makes a good configureable AP (though the 802.11 card
increases the power consumption by whopping 25% :)

These little computers sell already in some numbers, and can be a big
thing in developing countries where it may not always be possible to
have normal electricity supplies, and cost of computers can be
critical.  These devices sell under $100 in volumes.  

I would suggest to keep MATH_EMULATE in (and fixing it) instead of
dropping support or making separate soft-float port.  I have been
looking if MATH_EMULATE could be brought back to FreeBSD or
-msoft-float could work out there, and my current view is that making
a soft-float work seems equally complex as keeping MATH_EMULATE alive,
and does have a cost of keeping all separate installation
infrastructure and package trees.  MATH_EMULATE at least concentrates
the solution in one place, and allows binary compatibility (for those
who care).

I can understand the point that a year ago it would have looked a bit
odd to assume that non-fpu things would be back, but it would seem to
me a stroke of luck that it was not completely removed like they did
on FreeBSD.  Putting it back is much harder than fixing it.

FreeBSD 4.11 install still booted on above computer, but it does not
support things like USB CD drives, so installing turned out to be a
hassle (I did not go through it).  NetBSD 4.0 install booted but newfs
fails on trying to use floating point, apparently due to bug on
MATH_EMULATE.

I can donate above computers to anyone who wants to seriously look at
this.

Heikki

Steve Woodford <scw%netbsd.org@localhost> writes:
> On Sunday 13 January 2008 09:38:15 John Nemeth wrote:
> > On Jun 4,  8:04am, Steve Woodford wrote:
> > } For the record, I have a local port of NetBSD for the Linksys
> > WRT54GR, } which has an RDC-something-or-other SoC:
> > }
> > }  cpu0 at mainbus0: (uniprocessor)
> > }  cpu0: Cyrix 486DLC (486-class)
> >
> >      Wow!  I've almost forgotten about those things.  I'm surprised
> > that anybody is still using them and that Cyrix is still around.  I'm
> > sure that there are processors that are better and just as cheap that
> > can be used.
> 
> Keep in mind this is just the CPU core on a cheap and nasty 
> system-on-a-chip (RDC-R8610 if I recall). Chances are, RDC simply 
> licensed the core from whoever now owns the rights to Cyrix's 
> technology.
> 
> Cheers, Steve