diff mbox series

[09/12] x86: Do not raise inexact exception on truncl

Message ID 20231228172026.2013007-10-adhemerval.zanella@linaro.org
State Superseded
Headers show
Series Improve rounding to interger function for C23 | expand

Commit Message

Adhemerval Zanella Netto Dec. 28, 2023, 5:20 p.m. UTC 
It is not allowed anymore on ISO C23.

Checked on x86_64-linux-gnu and i686-linux-gnu.
---
 .../fpu/s_truncl.S => x86/fpu/s_truncl.c}     | 40 +++++++++----------
 sysdeps/x86_64/fpu/s_truncl.S                 | 36 -----------------
 2 files changed, 19 insertions(+), 57 deletions(-)
 rename sysdeps/{i386/fpu/s_truncl.S => x86/fpu/s_truncl.c} (61%)
 delete mode 100644 sysdeps/x86_64/fpu/s_truncl.S

Comments

H.J. Lu April 1, 2024, 2:14 p.m. UTC | #1 
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.
> ---
>  .../fpu/s_truncl.S => x86/fpu/s_truncl.c}     | 40 +++++++++----------
>  sysdeps/x86_64/fpu/s_truncl.S                 | 36 -----------------
>  2 files changed, 19 insertions(+), 57 deletions(-)
>  rename sysdeps/{i386/fpu/s_truncl.S => x86/fpu/s_truncl.c} (61%)
>  delete mode 100644 sysdeps/x86_64/fpu/s_truncl.S
>
> diff --git a/sysdeps/i386/fpu/s_truncl.S b/sysdeps/x86/fpu/s_truncl.c
> similarity index 61%
> rename from sysdeps/i386/fpu/s_truncl.S
> rename to sysdeps/x86/fpu/s_truncl.c
> index cfd4e75252..249b307004 100644
> --- a/sysdeps/i386/fpu/s_truncl.S
> +++ b/sysdeps/x86/fpu/s_truncl.c
> @@ -1,5 +1,5 @@
> -/* Truncate long double value.
> -   Copyright (C) 1997-2023 Free Software Foundation, Inc.
> +/* Round to integer, toward zero.  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
> @@ -16,25 +16,23 @@
>     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>
> -#include <machine/asm.h>
>
> -ENTRY(__truncl)
> -       fldt    4(%esp)
> -       subl    $32, %esp
> -       cfi_adjust_cfa_offset (32)
> -       fnstenv 4(%esp)
> -       movl    $0xc00, %edx
> -       orl     4(%esp), %edx
> -       movl    %edx, (%esp)
> -       fldcw   (%esp)
> -       frndint
> -       fnstsw
> -       andl    $0x1, %eax
> -       orl     %eax, 8(%esp)
> -       fldenv  4(%esp)
> -       addl    $32, %esp
> -       cfi_adjust_cfa_offset (-32)
> -       ret
> -END(__truncl)
> +long double
> +__truncl (long double x)
> +{
> +  fenv_t fenv;
> +  long double r;
> +
> +  libc_feholdexcept_setround_387 (&fenv, FE_TOWARDZERO);
> +  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 (__trunc, trunc)
> diff --git a/sysdeps/x86_64/fpu/s_truncl.S b/sysdeps/x86_64/fpu/s_truncl.S
> deleted file mode 100644
> index 8d319e68b0..0000000000
> --- a/sysdeps/x86_64/fpu/s_truncl.S
> +++ /dev/null
> @@ -1,36 +0,0 @@
> -/* Truncate long double value.
> -   Copyright (C) 1997-2023 Free Software Foundation, Inc.
> -   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/>.  */
> -
> -#include <libm-alias-ldouble.h>
> -#include <machine/asm.h>
> -
> -ENTRY(__truncl)
> -       fldt    8(%rsp)
> -       fnstenv -28(%rsp)
> -       movl    $0xc00, %edx
> -       orl     -28(%rsp), %edx
> -       movl    %edx, -32(%rsp)
> -       fldcw   -32(%rsp)
> -       frndint
> -       fnstsw
> -       andl    $0x1, %eax
> -       orl     %eax, -24(%rsp)
> -       fldenv  -28(%rsp)
> -       ret
> -END(__truncl)
> -libm_alias_ldouble (__trunc, trunc)
> --
> 2.34.1
>
diff mbox series

Patch

diff --git a/sysdeps/i386/fpu/s_truncl.S b/sysdeps/x86/fpu/s_truncl.c
similarity index 61%
rename from sysdeps/i386/fpu/s_truncl.S
rename to sysdeps/x86/fpu/s_truncl.c
index cfd4e75252..249b307004 100644
--- a/sysdeps/i386/fpu/s_truncl.S
+++ b/sysdeps/x86/fpu/s_truncl.c
@@ -1,5 +1,5 @@ 
-/* Truncate long double value.
-   Copyright (C) 1997-2023 Free Software Foundation, Inc.
+/* Round to integer, toward zero.  x86 version.
+   Copyright (C) 2023 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
 
    The GNU C Library is free software; you can redistribute it and/or
@@ -16,25 +16,23 @@ 
    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>
-#include <machine/asm.h>
 
-ENTRY(__truncl)
-	fldt	4(%esp)
-	subl	$32, %esp
-	cfi_adjust_cfa_offset (32)
-	fnstenv	4(%esp)
-	movl	$0xc00, %edx
-	orl	4(%esp), %edx
-	movl	%edx, (%esp)
-	fldcw	(%esp)
-	frndint
-	fnstsw
-	andl	$0x1, %eax
-	orl	%eax, 8(%esp)
-	fldenv	4(%esp)
-	addl	$32, %esp
-	cfi_adjust_cfa_offset (-32)
-	ret
-END(__truncl)
+long double
+__truncl (long double x)
+{
+  fenv_t fenv;
+  long double r;
+
+  libc_feholdexcept_setround_387 (&fenv, FE_TOWARDZERO);
+  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 (__trunc, trunc)
diff --git a/sysdeps/x86_64/fpu/s_truncl.S b/sysdeps/x86_64/fpu/s_truncl.S
deleted file mode 100644
index 8d319e68b0..0000000000
--- a/sysdeps/x86_64/fpu/s_truncl.S
+++ /dev/null
@@ -1,36 +0,0 @@ 
-/* Truncate long double value.
-   Copyright (C) 1997-2023 Free Software Foundation, Inc.
-   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/>.  */
-
-#include <libm-alias-ldouble.h>
-#include <machine/asm.h>
-
-ENTRY(__truncl)
-	fldt	8(%rsp)
-	fnstenv	-28(%rsp)
-	movl	$0xc00, %edx
-	orl	-28(%rsp), %edx
-	movl	%edx, -32(%rsp)
-	fldcw	-32(%rsp)
-	frndint
-	fnstsw
-	andl	$0x1, %eax
-	orl	%eax, -24(%rsp)
-	fldenv	-28(%rsp)
-	ret
-END(__truncl)
-libm_alias_ldouble (__trunc, trunc)