Subject: Re: NetBSD & Mac
To: None <MacBSD-general@NetBSD.ORG>
From: Henry B. Hotz <>
List: macbsd-general
Date: 04/03/1995 13:44:42
>In comp.unix.bsd.netbsd.misc you write:
>>In article <>, (Bob
>>James) wrote:
>>At one point, and I don't remember what I did to get there, it advised me
>>that my FPU was not supported. I'm using a 68882, not a 68881, but it is a
>>shock that it doesn't work. Do you think that could be my problem??
>I find it hard to believe, but if it is true, then there might be some
>assumption that '020 always uses a '881, not a '882.  I'm passing this
>message to macbsd-general mailing list, so the developers will get
>this, too.  Although I can't think of that much difference between
>'881 and '882 that would cause the kernel not to work...

I also find it hard to believe.  In any case there is no advantage to using
an '882 with an '020.  The only substantive difference between the two is
that the '882 will allow you to overlap the format conversion step in FP
load/stores with operation of the '030 chip.  But that *only* happens if
you also have a 68030 CPU.

The chips are so similar that they take the same number of clock cycles for
*all* floating point operations.

Henry B. Hotz

The opinions expressed are my own,
not Loral's, and not Librascope's.