[PATCH] powerpc: POWER7 optimised memcpy using VMX and enhanced prefetch

David Laight David.Laight at ACULAB.COM
Wed Dec 19 01:14:40 EST 2012

> >>        dcbt    r0,r8,0b01010   /* GO */
> >> .machine pop
> >
> > Jimi, are you using an "old" binutils from before my patch that
> > changed the operand order for these types of instructions?
> >
> >    http://sourceware.org/ml/binutils/2009-02/msg00044.html
> Actually, this confused me as well, that embedded has the same
> instruction encoding but different mnemonic.

That it utterly horrid!

> I was under the impression that the assembler made no instruction decisions based on CPU.
> So your only hint would be that '0b' prefix.
> Does AS even see that?

Or maybe see the 'r' prefix.
I know they tend to be absent making ppc asm even more unreadable.
It isn't as though the mnemonics were designed at a time when
the source file size or difference in decode time (or code space)
would be significant.

Otherwise it is a complete recipe for disaster.


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