>> Anyway, this asm code has bugs, as do both the current C version in
>> the
>> kernel, and the code I posted. We need to do better :-)
>
> The only bug I know of in the asm code is the behaviour when the count
> is zero. Do you know of any other?
No, that's the bug I meant. Sorry for using s
Segher Boessenkool writes:
> Anyway, this asm code has bugs, as do both the current C version in the
> kernel, and the code I posted. We need to do better :-)
The only bug I know of in the asm code is the behaviour when the count
is zero. Do you know of any other?
Paul.
___
>> Do we have any indication that it performs better than the C one ?
>
> I would expect it to, given that the assembler one has two branches in
> the per-byte loop compared to 3 in the C version.
But really, does it matter for strncmp() in the kernel?
Anyway, this asm code has bugs, as do both t
Benjamin Herrenschmidt writes:
> Do we have any indication that it performs better than the C one ?
I would expect it to, given that the assembler one has two branches in
the per-byte loop compared to 3 in the C version.
Paul.
___
Linuxppc-dev mailing
>> Even if it was logically faster (which I still doubt) it's a hell of
>> a lot
>> of cache lines to waste.
Yeah, 1 on 64-bit and 3 on 32-bit, that's a terrible lot.
> Indeed, but there are some corner cases that the C code handles. Like
> a length of 0 which may lead to infinite loop in the as
Gabriel Paubert <[EMAIL PROTECTED]> writes:
> Now that I think a bit more about it, I believe that the C version is
> incorrect: the clrldi/extsb dance takes a value between -255 and +255
> and collapses it into the -128 to 127 range, meaning that the return
> value may be wrong if we rely on the
On Fri, Feb 29, 2008 at 10:56:45PM -0500, Steven Rostedt wrote:
>
> On Sat, 1 Mar 2008, Benjamin Herrenschmidt wrote:
> >
> > Do we have any indication that it performs better than the C one ?
>
> See below.
>
> >
> > Ben.
> >
>
> > >
> > > +_GLOBAL(strncmp)
> > > + mtctr r5
> > > + addir
On Sat, 1 Mar 2008, Benjamin Herrenschmidt wrote:
>
> Do we have any indication that it performs better than the C one ?
See below.
>
> Ben.
>
> >
> > +_GLOBAL(strncmp)
> > + mtctr r5
> > + addir5,r3,-1
> > + addir4,r4,-1
> > +1: lbzur3,1(r5)
> > + cmpwi 1,r3,0
> > + l
On Fri, 2008-02-29 at 11:04 -0500, Steven Rostedt wrote:
> strncmp is defined in assembly for bootup, but it is not defined in the
> normal running kernel. This patch takes the strncmp code from the bootup
> and copies it to the kernel proper.
>
> Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]>
strncmp is defined in assembly for bootup, but it is not defined in the
normal running kernel. This patch takes the strncmp code from the bootup
and copies it to the kernel proper.
Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]>
---
arch/powerpc/kernel/ppc_ksyms.c |1 +
arch/powerpc/lib/st
10 matches
Mail list logo
