Re: [PATCH] ppc: Fix extr_d() on 32-bit PPC

[Paulo César Pereira de Andrade]

Em sáb., 27 de ago. de 2022 às 20:30, Paul Cercueil
<paul@crapouillou.net> escreveu:
>
> Note that with your recent SQRT patches and this one, the checks all
> pass on PowerPC 32-bit now.

  That is great news.
  Thanks for letting me know!

> Cheers,
> -Paul
>
>
> Le sam., août 27 2022 at 16:17:30 +0100, Paul Cercueil
> <paul@crapouillou.net> a écrit :
> > The FCFID instruction is only available on 64-bit PowerPC. Therefore
> > it
> > is necesary to use a software mechanism to convert integers to
> > floating-point on 32-bit PowerPC.
> >
> > Tested and working on PowerPC-32 big-endian and little-endian.
> >
> > Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> > ---
> >  lib/jit_ppc-fpu.c | 31 ++++++++++++++++++++++++-------
> >  1 file changed, 24 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/jit_ppc-fpu.c b/lib/jit_ppc-fpu.c
> > index 387cc6f..dd66d03 100644
> > --- a/lib/jit_ppc-fpu.c
> > +++ b/lib/jit_ppc-fpu.c
> > @@ -484,23 +484,40 @@ _movi_d(jit_state_t *_jit, jit_int32_t r0,
> > jit_float64_t *i0)
> >       ldi_d(r0, (jit_word_t)i0);
> >  }
> >
> > -/* should only work on newer ppc (fcfid is a ppc64 instruction) */
> >  static void
> >  _extr_d(jit_state_t *_jit, jit_int32_t r0, jit_int32_t r1)
> >  {
> >  #  if __WORDSIZE == 32
> > -    jit_int32_t              reg;
> > +    jit_int32_t              reg, freg, off1, off2;
> > +
> > +#  if __BYTE_ORDER == __BIG_ENDIAN
> > +    off1 = alloca_offset - 8;
> > +    off2 = alloca_offset - 4;
> > +#  else
> > +    off1 = alloca_offset - 4;
> > +    off2 = alloca_offset - 8;
> > +#  endif
> > +
> >      reg = jit_get_reg(jit_class_gpr);
> > -    rshi(rn(reg), r1, 31);
> > -    /* use reserved 8 bytes area */
> > -    stxi(alloca_offset - 4, _FP_REGNO, r1);
> > -    stxi(alloca_offset - 8, _FP_REGNO, rn(reg));
> > +    freg = jit_get_reg(jit_class_fpr);
> > +
> > +    movi(rn(reg), 0x43300000);
> > +    stxi_i(off1, _FP_REGNO, rn(reg));
> > +    movi(rn(reg), 0x80000000);
> > +    stxi_i(off2, _FP_REGNO, rn(reg));
> > +    ldxi_d(rn(freg), _FP_REGNO, alloca_offset - 8);
> > +    xorr(rn(reg), r1, rn(reg));
> > +    stxi_i(off2, _FP_REGNO, rn(reg));
> > +    ldxi_d(r0, _FP_REGNO, alloca_offset - 8);
> > +    subr_d(r0, r0, rn(freg));
> > +
> >      jit_unget_reg(reg);
> > +    jit_unget_reg(freg);
> >  #  else
> >      stxi(alloca_offset - 8, _FP_REGNO, r1);
> > -#  endif
> >      ldxi_d(r0, _FP_REGNO, alloca_offset - 8);
> >      FCFID(r0, r0);
> > +#  endif
> >  }
> >
> >  static void
> > --
> > 2.35.1
> >
>
>