On Mon, 29 Nov 2004, Joe Laffey wrote:

> On Mon, 29 Nov 2004, Frederick Bruckman wrote:
>
>> In article 
>> <Pine.NEB.4.61.0411281228490.18889@phenotype.laffeycomputer.com>,
>> 	joe@laffeycomputer.com (Joe Laffey) writes:
>>> 
>>> I should enable FPU_EMULATE, obviously, but what about FPSP?

>> With a 68LC040, FPSP is doing you no good at all. That module is an
>> exception to the "no floating point in kernel". It consists of 68040
>> floating points instructions, supplied by Motorola (as machine code)
>> to exactly emulate the 68881 FP instructions.  As you don't have a
>> 68040 floating point unit, the kernel should have set up the trap
>> table to go into FPU_EMULATE for any FP traps, so your system never
>> uses any of the FPSP code.
>
> Interesting. So I should be able to comment out FPSP if I use FPU_EMULATE, 
> regardless of how other binaries on the system are built then , right?

That's what I said. ;-)

>> You're lucky that FPU_EMULATE works at all; many LC040's are broken
>> in some way which makes it impossible to emulate FP correctly.  Even
>> so, you'll probably get better performance if you build all binaries
>> with "-msoft-float"--in which case you won't even need FPU_EMULATE--as
>> that saves the overhead of a "trap".  If you do that, you'll also save
>> the kernel memory that FPU_EMULATE uses.  You could update to a
>> soft-float snapshot from within NetBSD, using "tar -C / -xzpf ...".
>> If it's a current snapshot, don't forget to update the kernel first.
>
> I am currently running the kernel and userland built with soft-float from 
> ftp.ziaspace.com (RC5). Since this machine has only 8 megs I am trying to 
> build a much more optimzed and smaller kernel.

So you don't need FPU_EMULATE, either.


Frederick