[PATCH] powerpc: provide __bswapdi2
Gabriel Paubert
paubert at iram.es
Mon May 13 17:33:19 EST 2013
On Mon, May 13, 2013 at 05:09:59PM +1000, Michael Neuling wrote:
> David Woodhouse <dwmw2 at infradead.org> wrote:
>
> > From: David Woodhouse <David.Woodhouse at intel.com>
> >
> > Some versions of GCC apparently expect this to be provided by libgcc.
> >
> > Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
> > ---
> > Untested.
> >
> > diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S
> > index 19e096b..f077dc2 100644
> > --- a/arch/powerpc/kernel/misc_32.S
> > +++ b/arch/powerpc/kernel/misc_32.S
> > @@ -657,6 +657,17 @@ _GLOBAL(__ucmpdi2)
> > li r3,2
> > blr
> >
> > +_GLOBAL(__bswapdi2)
> > + rlwinm 10,4,8,0xffffffff
> > + rlwinm 11,3,8,0xffffffff
> > + rlwimi 10,4,24,0,7
> > + rlwimi 11,3,24,0,7
> > + rlwimi 10,4,24,16,23
> > + rlwimi 11,3,24,16,23
> > + mr 4,11
> > + mr 3,10
> > + blr
> > +
>
> This doesn't work for me but the below does:
>
> _GLOBAL(__bswapdi2)
> rotlwi r9,r4,8
> rotlwi r10,r3,8
> rlwimi r9,r4,24,0,7
> rlwimi r10,r3,24,0,7
> rlwimi r9,r4,24,16,23
> rlwimi r10,r3,24,16,23
> mr r4,r10
> mr r3,r9
> blr
>
Actually, I'd swap the two mr instructions to never
have an instruction that uses the result from the
previous one.
> stolen from GCC -02 output of:
> unsigned long long __bswapdi2(unsigned long long x)
> {
> return ((x & 0x00000000000000ffULL) << 56) |
> ((x & 0x000000000000ff00ULL) << 40) |
> ((x & 0x0000000000ff0000ULL) << 24) |
> ((x & 0x00000000ff000000ULL) << 8) |
> ((x & 0x000000ff00000000ULL) >> 8) |
> ((x & 0x0000ff0000000000ULL) >> 24) |
> ((x & 0x00ff000000000000ULL) >> 40) |
> ((x & 0xff00000000000000ULL) >> 56);
> }
>
> > _GLOBAL(abs)
> > srawi r4,r3,31
> > xor r3,r3,r4
> > diff --git a/arch/powerpc/kernel/misc_64.S b/arch/powerpc/kernel/misc_64.S
> > index 5cfa800..3b2e6e8 100644
> > --- a/arch/powerpc/kernel/misc_64.S
> > +++ b/arch/powerpc/kernel/misc_64.S
> > @@ -234,6 +234,18 @@ _GLOBAL(__flush_dcache_icache)
> > isync
> > blr
> >
> > +_GLOBAL(__bswapdi2)
> > + srdi 8,3,32
> > + rlwinm 7,3,8,0xffffffff
> > + rlwimi 7,3,24,0,7
> > + rlwinm 9,8,8,0xffffffff
> > + rlwimi 7,3,24,16,23
> > + rlwimi 9,8,24,0,7
> > + rlwimi 9,8,24,16,23
> > + sldi 7,7,32
> > + or 7,7,9
> > + mr 3,7
> > + blr
>
> This works but we should add "r" to the register names.
>
And merge the last two instructions as a single "or r3,r7,r9".
Gabriel
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