Xiamin Raahauge wrote:
> 
> On Tue, 13 Jan 1998, Bill Studenmund wrote:
> > > btw,  My config file doesn't include FPU_EMULATE or FPSP.
> > 
> > If the kernel never touches what's in the FP registers, then the interrupt
> > service routines don't have to bother saving & restoring their contents.
> > 
> > And for the macs, since some machines lack FPU's, imagine what'd happen if
> > the code to emulate the FPU ended up using FPU instructions!
> > 
> > The main problem is the register saving one. There are key points where
> > we don't save the FP regs since we're not supposed to touch them. W/o
> > -msoft-float, the FP regs were magically changing on the user-land programs.
> > 
> > Things should run fine on your machine w/ just -Dmc68030 and -msoft-float.
> I've always wondered this, what exactly does FPSP do? I have it in my
> config file, mostly because I have no idea what it is.
> I have a Q650, so I do have a FPU.

The FPSP is Motorola's Floating Point Software Package (or something
reasonably close to that).  Basically, it's a set of routines that emulate
in software those functions of the 68881/68882 FPU coprocessor which the
68040's onboard FPU do not perform.  I don't believe that any of these
emulated functions are ones that are used very often.  I'd recommend
looking at the FPSP support code (sys/arch/m68k/fpsp) or the Motorola
68040 User's Manual (available online in PDF format), for more information
on this...

...does that answer your question?

Later.

-- 
Colin Wood                                 cwood@ichips.intel.com
Component Design Engineer - MD6                 Intel Corporation
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I speak only on my own behalf, not for my employer.