Re: [PATCH v2 3/4] Refactor sigcontextinfo.h

[Florian Weimer <fweimer at redhat dot com>]

* Adhemerval Zanella:

> diff --git a/sysdeps/unix/sysv/linux/m68k/register-dump.h b/sysdeps/unix/sysv/linux/m68k/register-dump.h
> index b9941e813e..69f8e4c3f0 100644
> --- a/sysdeps/unix/sysv/linux/m68k/register-dump.h
> +++ b/sysdeps/unix/sysv/linux/m68k/register-dump.h
>  static void
> -register_dump (int fd, struct sigcontext *ctx)
> +register_dump (int fd, struct ucontext_t *ctx)
>  {
> +  /* Linux does not save the FP state in case of emulated floating point.  */
> +#ifndef __mcoldfire__
> +  __asm__ volatile (".chip 68k/68881\n\t"
> +                    "fmovem.x %%fp0-%%fp7, %0\n\t"
> +                    "fmovem.l %%fpcr, %1\n\t"
> +                    "fmovem.l %%fpsr, %2\n\t"
> +                    "fmovem.l %%fpiar, %3\n\t"
> +                    ".chip 68k"
> +                    : "=m" (*ctx->uc_mcontext.fpregs.f_fpregs),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr)
> +                    : /* no inputs.  */
> +                    : "memory");
> +#elif defined __mcffpu__
> +  __asm__ volatile ("fmovemd %%fp0-%%fp7, %0\n\t"
> +                    "fmovel  %%fpcr, %1\n\t"
> +                    "fmovel  %%fpsr, %2\n\t"
> +                    "fmovel  %%fpiar, %3\n\t"
> +                    : "=m" (*ctx->uc_mcontext.fpregs.f_fpregs),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr),
> +                      "=m" (ctx->uc_mcontext.fpregs.f_pcr)
> +                    : /* no inputs.  */
> +                    : "memory");
> +#endif

f_pcr used three times in both cases looks like a cut-and-paste error.
If this is correct, it needs a comment.

I'm surprised that this does not need a softfloat conditional.  Is the
sense of the comment really correct?  Based on the code, the registers
are saved by the kernel in the softfloat case (the opposite sense)
because there is no code to overwrite it.

Thanks,
Florian