Re: load_unaligned() and "uld" instruction

["Kevin D. Kissell" <kevink@mips.com>]

> > > Why will it crash 32-bit CPUs?  On my R5432 CPU, the lwl/lwr sequence
> > > executes just fine.
> > >
> > > Or do you mean it will crash SOME 32-bit CPUs?  Do those 32-bit CPUs
> > > support lwl or lwr?  If they don't, they should generate a reserved
> > > instruction exception.  If they do, I don't see any problem.
> > 
> > Please re-read my previous message.  I wasn't talking about the
> > MIPS I lwl/lwr sequence for loading an unaligned 32-bit word, I was
> > talking about the MIPS III ldl/ldr sequence for loading an unaligned
> > 64-bit doubleword.
> > 
> >             Kevin K.
> 
> Ahh, my bad.  
> 
> Although the usb does use get_unaligned(u64) (ldl/ldr), it actually does
> not run into it - at least in my test so far.  That probably explains
> why my fix runs on the R5432 CPU so far.

The 5432 may have a 32-bit external bus, but it's still (as far
as I know) a 64-bit part internally, so as long as you're executing
in kernel mode, the ldl/ldr's should work as designed.

            Kevin K.