Subject: mc68882
To: Kenneth Stailey <kstailey@owl.dol-esa.gov>
From: Duncan McRae <duncanm@tplrd.tpl.oz.au>
List: port-sun3
Date: 07/19/1995 17:29:25
>>>>> Ken Stailey <kstailey@owl.dol-esa.gov> writes:

    Ken> I read on
    Ken> http://www.unix-ag.uni-kl.de/~hardware/Sun3/sun3main.html
    Ken> that you can pull the mc68881 out of your 3/60 and put in a
    Ken> mc68882.

    Ken> Has anyone tried this?  Is there any reason to believe that
    Ken> NetBSD would have a problem with this?  Is it likely to make
    Ken> a noticeable improvement, say when running X?

    Ken> ~Ken

Actually, you can do both 68882 and 68030,

I stuck a '8882/'030 pair in my 3/60 (ok, so it doesn't run netBSD,
but ScumOS4.1.1 works ok, as does X and anything else I throw at it).

The '8882 just slots in. Should give about 10-15% improvement
on math instructions.

The '030 requires that you get into your box with a solder sucker and
solder an (appropriately-shaped) socket in the empty pads next to the
'020. Pull out the '020 and stick an '030 in your new socket and away
you go.

Of course, the on-chip MMU and cache aren't enabled, and I don't know
of the measure of improvement with the '030.
I _do_ compile my stuff with -m68030 flag under gcc, so I might get a
few extra instructions (unknown).

Worth it? I dunno, I just had them lying around, and they're a 50MHz
pair so I should have less problems when I get around to bumping up my
clock rate (25MHz is the go, I hear).

Well, I enjoyed getting the solder out of all those vias, anyway :)