[PATCH v2 07/10] x86: Do not raise inexact exception on truncl

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

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 dfd0ca4a57..59614cd006 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) 1997-2024 Free Software Foundation, Inc.
+/* Round to integer, toward zero.  x86 version.
+   Copyright (C) 2024 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 e3d64a84e8..0000000000
--- a/sysdeps/x86_64/fpu/s_truncl.S
+++ /dev/null
@@ -1,36 +0,0 @@
-/* Truncate long double value.
-   Copyright (C) 1997-2024 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