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

[Paul Cercueil]

Hi Paulo,

Le lun., août 29 2022 at 16:44:35 -0300, Paulo César Pereira de 
Andrade <paulo.cesar.pereira.de.andrade@gmail.com> a écrit :
> 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!

No problem.

One thing bothers me though - extr_f() and extr_d() are defined to the 
same thing; but doubles and floats are different, how does this work?

-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
> >  >