Re: [PATCH 07/12] x86: Do not raise inexact exception on ceill

["H.J. Lu" <hjl.tools@gmail.com>]

On Thu, Dec 28, 2023 at 9:23 AM Adhemerval Zanella
<adhemerval.zanella@linaro.org> wrote:
>
> It is not allowed anymore on ISO C23.
>
> Checked on x86_64-linux-gnu and i686-linux-gnu.
> ---
>  sysdeps/i386/fpu/s_ceill.S   | 39 ------------------------------------
>  sysdeps/x86/fpu/s_ceill.c    | 38 +++++++++++++++++++++++++++++++++++
>  sysdeps/x86_64/fpu/s_ceill.S | 34 -------------------------------
>  3 files changed, 38 insertions(+), 73 deletions(-)
>  delete mode 100644 sysdeps/i386/fpu/s_ceill.S
>  create mode 100644 sysdeps/x86/fpu/s_ceill.c
>  delete mode 100644 sysdeps/x86_64/fpu/s_ceill.S
>
> diff --git a/sysdeps/i386/fpu/s_ceill.S b/sysdeps/i386/fpu/s_ceill.S
> deleted file mode 100644
> index a551fce7f9..0000000000
> --- a/sysdeps/i386/fpu/s_ceill.S
> +++ /dev/null
> @@ -1,39 +0,0 @@
> -/*
> - * Public domain.
> - */
> -
> -#include <libm-alias-ldouble.h>
> -#include <machine/asm.h>
> -
> -RCSID("$NetBSD: $")
> -
> -ENTRY(__ceill)
> -       fldt    4(%esp)
> -       subl    $32,%esp
> -       cfi_adjust_cfa_offset (32)
> -
> -       fnstenv 4(%esp)                 /* store fpu environment */
> -
> -       /* We use here %edx although only the low 1 bits are defined.
> -          But none of the operations should care and they are faster
> -          than the 16 bit operations.  */
> -       movl    $0x0800,%edx            /* round towards +oo */
> -       orl     4(%esp),%edx
> -       andl    $0xfbff,%edx
> -       movl    %edx,(%esp)
> -       fldcw   (%esp)                  /* load modified control word */
> -
> -       frndint                         /* round */
> -
> -       /* Preserve "invalid" exceptions from sNaN input.  */
> -       fnstsw
> -       andl    $0x1, %eax
> -       orl     %eax, 8(%esp)
> -
> -       fldenv  4(%esp)                 /* restore original environment */
> -
> -       addl    $32,%esp
> -       cfi_adjust_cfa_offset (-32)
> -       ret
> -END (__ceill)
> -libm_alias_ldouble (__ceil, ceil)
> diff --git a/sysdeps/x86/fpu/s_ceill.c b/sysdeps/x86/fpu/s_ceill.c
> new file mode 100644
> index 0000000000..96c901e383
> --- /dev/null
> +++ b/sysdeps/x86/fpu/s_ceill.c
> @@ -0,0 +1,38 @@
> +/* Return smallest integral value not less than argument.  x86 version.
> +   Copyright (C) 2023 Free Software Foundation, Inc.

2024.

> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#define NO_MATH_REDIRECT
> +#include <math.h>
> +#include <fenv_private.h>
> +#include <libm-alias-ldouble.h>
> +
> +long double
> +__ceill (long double x)
> +{
> +  fenv_t fenv;
> +  long double r;
> +
> +  libc_feholdexcept_setround_387 (&fenv, FE_UPWARD);
> +  asm volatile ("frndint" : "=t" (r) : "0" (x));
> +  /* Preserve "invalid" exceptions from sNaN input.  */
> +  fenv.__status_word |= libc_fetestexcept_387 (FE_INVALID);
> +  libc_fesetenv_387 (&fenv);
> +
> +  return r;
> +}
> +libm_alias_ldouble (__ceil, ceil)
> diff --git a/sysdeps/x86_64/fpu/s_ceill.S b/sysdeps/x86_64/fpu/s_ceill.S
> deleted file mode 100644
> index 16dbecd56d..0000000000
> --- a/sysdeps/x86_64/fpu/s_ceill.S
> +++ /dev/null
> @@ -1,34 +0,0 @@
> -/*
> - * Public domain.
> - */
> -
> -#include <libm-alias-ldouble.h>
> -#include <machine/asm.h>
> -
> -
> -ENTRY(__ceill)
> -       fldt    8(%rsp)
> -
> -       fnstenv -28(%rsp)               /* store fpu environment */
> -
> -       /* We use here %edx although only the low 1 bits are defined.
> -          But none of the operations should care and they are faster
> -          than the 16 bit operations.  */
> -       movl    $0x0800,%edx            /* round towards +oo */
> -       orl     -28(%rsp),%edx
> -       andl    $0xfbff,%edx
> -       movl    %edx,-32(%rsp)
> -       fldcw   -32(%rsp)               /* load modified control word */
> -
> -       frndint                         /* round */
> -
> -       /* Preserve "invalid" exceptions from sNaN input.  */
> -       fnstsw
> -       andl    $0x1, %eax
> -       orl     %eax, -24(%rsp)
> -
> -       fldenv  -28(%rsp)               /* restore original environment */
> -
> -       ret
> -END (__ceill)
> -libm_alias_ldouble (__ceil, ceil)
> --
> 2.34.1
>


-- 
H.J.