arc: add support for fenv from glibc

extra/Configs/Config.in.arch

@@ -165,6 +165,7 @@ config UCLIBC_HAS_FENV
 	depends on UCLIBC_HAS_FLOATS
 	depends on TARGET_i386 || \
 		   TARGET_aarch64 || \
+		   TARGET_arc || \
 		   TARGET_arm || \
 		   TARGET_m68k || \
 		   TARGET_metag || \

libm/arc/Makefile.arch

@@ -0,0 +1,16 @@
+# Makefile for uClibc-ng
+# Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+
+ifeq ($(UCLIBC_HAS_FENV),y)
+libm_ARCH_SRC:=$(wildcard $(libm_ARCH_DIR)/*.c)
+libm_ARCH_OBJ:=$(patsubst $(libm_ARCH_DIR)/%.c,$(libm_ARCH_OUT)/%.o,$(libm_ARCH_SRC))
+endif
+
+libm_ARCH_OBJS:=$(libm_ARCH_OBJ)
+
+ifeq ($(DOPIC),y)
+libm-a-y+=$(libm_ARCH_OBJS:.o=.os)
+else
+libm-a-y+=$(libm_ARCH_OBJS)
+endif
+libm-so-y+=$(libm_ARCH_OBJS:.o=.os)

libm/arc/fclrexcpt.c

@@ -0,0 +1,34 @@
+/* Clear given exceptions in current floating-point environment.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+
+int
+feclearexcept (int excepts)
+{
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+
+  /* Clear the relevant bits, FWE is preserved.  */
+  fpsr &= ~excepts;
+
+  _FPU_SETS (fpsr);
+
+  return 0;
+}

libm/arc/fegetenv.c

@@ -0,0 +1,33 @@
+/* Store current floating-point environment.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+
+int
+fegetenv (fenv_t *envp)
+{
+  unsigned int fpcr;
+  unsigned int fpsr;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETS (fpsr);
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+
+  return 0;
+}

libm/arc/fegetmode.c

@@ -0,0 +1,30 @@
+/* Store current floating-point control modes.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+
+int
+fegetmode (femode_t *modep)
+{
+  unsigned int fpcr;
+
+  _FPU_GETCW (fpcr);
+  *modep = fpcr;
+
+  return 0;
+}

libm/arc/fegetround.c

@@ -0,0 +1,28 @@
+/* Return current rounding direction.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fenv_private.h"
+
+int
+fegetround (void)
+{
+  unsigned int fpcr;
+  _FPU_GETCW (fpcr);
+
+  return (fpcr >> __FPU_RND_SHIFT) & __FPU_RND_MASK;
+}

libm/arc/feholdexcpt.c

@@ -0,0 +1,39 @@
+/* Store current floating-point environment and clear exceptions.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fenv_private.h"
+
+int
+feholdexcept (fenv_t *envp)
+{
+  unsigned int fpcr;
+  unsigned int fpsr;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETS (fpsr);
+
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+
+  fpsr &= ~FE_ALL_EXCEPT;
+
+  _FPU_SETCW (fpcr);
+  _FPU_SETS (fpsr);
+
+  return 0;
+}

libm/arc/fenv_private.h

@@ -0,0 +1,326 @@
+/* Optimized inline fenv.h functions for libm.  Generic version.
+   Copyright (C) 2011-2025 Free Software Foundation, Inc.
+
+   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/>.  */
+
+#ifndef _FENV_PRIVATE_H
+#define _FENV_PRIVATE_H 1
+
+#include <fenv.h>
+#include "get-rounding-mode.h"
+
+/* The standards only specify one variant of the fenv.h interfaces.
+   But at least for some architectures we can be more efficient if we
+   know what operations are going to be performed.  Therefore we
+   define additional interfaces.  By default they refer to the normal
+   interfaces.  */
+
+static __always_inline void
+default_libc_feholdexcept (fenv_t *e)
+{
+  (void) feholdexcept (e);
+}
+
+#ifndef libc_feholdexcept
+# define libc_feholdexcept  default_libc_feholdexcept
+#endif
+#ifndef libc_feholdexceptf
+# define libc_feholdexceptf default_libc_feholdexcept
+#endif
+#ifndef libc_feholdexceptl
+# define libc_feholdexceptl default_libc_feholdexcept
+#endif
+
+static __always_inline void
+default_libc_fesetround (int r)
+{
+  (void) fesetround (r);
+}
+
+#ifndef libc_fesetround
+# define libc_fesetround  default_libc_fesetround
+#endif
+#ifndef libc_fesetroundf
+# define libc_fesetroundf default_libc_fesetround
+#endif
+#ifndef libc_fesetroundl
+# define libc_fesetroundl default_libc_fesetround
+#endif
+
+static __always_inline void
+default_libc_feholdexcept_setround (fenv_t *e, int r)
+{
+  feholdexcept (e);
+  fesetround (r);
+}
+
+#ifndef libc_feholdexcept_setround
+# define libc_feholdexcept_setround  default_libc_feholdexcept_setround
+#endif
+#ifndef libc_feholdexcept_setroundf
+# define libc_feholdexcept_setroundf default_libc_feholdexcept_setround
+#endif
+#ifndef libc_feholdexcept_setroundl
+# define libc_feholdexcept_setroundl default_libc_feholdexcept_setround
+#endif
+
+#ifndef libc_feholdsetround_53bit
+# define libc_feholdsetround_53bit libc_feholdsetround
+#endif
+
+#ifndef libc_fetestexcept
+# define libc_fetestexcept  fetestexcept
+#endif
+#ifndef libc_fetestexceptf
+# define libc_fetestexceptf fetestexcept
+#endif
+#ifndef libc_fetestexceptl
+# define libc_fetestexceptl fetestexcept
+#endif
+
+static __always_inline void
+default_libc_fesetenv (fenv_t *e)
+{
+  (void) fesetenv (e);
+}
+
+#ifndef libc_fesetenv
+# define libc_fesetenv  default_libc_fesetenv
+#endif
+#ifndef libc_fesetenvf
+# define libc_fesetenvf default_libc_fesetenv
+#endif
+#ifndef libc_fesetenvl
+# define libc_fesetenvl default_libc_fesetenv
+#endif
+
+static __always_inline void
+default_libc_feupdateenv (fenv_t *e)
+{
+  (void) feupdateenv (e);
+}
+
+#ifndef libc_feupdateenv
+# define libc_feupdateenv  default_libc_feupdateenv
+#endif
+#ifndef libc_feupdateenvf
+# define libc_feupdateenvf default_libc_feupdateenv
+#endif
+#ifndef libc_feupdateenvl
+# define libc_feupdateenvl default_libc_feupdateenv
+#endif
+
+#ifndef libc_feresetround_53bit
+# define libc_feresetround_53bit libc_feresetround
+#endif
+
+static __always_inline int
+default_libc_feupdateenv_test (fenv_t *e, int ex)
+{
+  int ret = fetestexcept (ex);
+  feupdateenv (e);
+  return ret;
+}
+
+#ifndef libc_feupdateenv_test
+# define libc_feupdateenv_test  default_libc_feupdateenv_test
+#endif
+#ifndef libc_feupdateenv_testf
+# define libc_feupdateenv_testf default_libc_feupdateenv_test
+#endif
+#ifndef libc_feupdateenv_testl
+# define libc_feupdateenv_testl default_libc_feupdateenv_test
+#endif
+
+/* Save and set the rounding mode.  The use of fenv_t to store the old mode
+   allows a target-specific version of this function to avoid converting the
+   rounding mode from the fpu format.  By default we have no choice but to
+   manipulate the entire env.  */
+
+#ifndef libc_feholdsetround
+# define libc_feholdsetround  libc_feholdexcept_setround
+#endif
+#ifndef libc_feholdsetroundf
+# define libc_feholdsetroundf libc_feholdexcept_setroundf
+#endif
+#ifndef libc_feholdsetroundl
+# define libc_feholdsetroundl libc_feholdexcept_setroundl
+#endif
+
+/* ... and the reverse.  */
+
+#ifndef libc_feresetround
+# define libc_feresetround  libc_feupdateenv
+#endif
+#ifndef libc_feresetroundf
+# define libc_feresetroundf libc_feupdateenvf
+#endif
+#ifndef libc_feresetroundl
+# define libc_feresetroundl libc_feupdateenvl
+#endif
+
+/* ... and a version that also discards exceptions.  */
+
+#ifndef libc_feresetround_noex
+# define libc_feresetround_noex  libc_fesetenv
+#endif
+#ifndef libc_feresetround_noexf
+# define libc_feresetround_noexf libc_fesetenvf
+#endif
+#ifndef libc_feresetround_noexl
+# define libc_feresetround_noexl libc_fesetenvl
+#endif
+
+#ifndef HAVE_RM_CTX
+# define HAVE_RM_CTX 0
+#endif
+
+
+/* Default implementation using standard fenv functions.
+   Avoid unnecessary rounding mode changes by first checking the
+   current rounding mode.  Note the use of unlikely is
+   important for performance.  */
+
+static __always_inline void
+default_libc_feholdsetround_ctx (struct rm_ctx *ctx, int round)
+{
+  ctx->updated_status = false;
+
+  /* Update rounding mode only if different.  */
+  if (unlikely (round != get_rounding_mode ()))
+    {
+      ctx->updated_status = true;
+      fegetenv (&ctx->env);
+      fesetround (round);
+    }
+}
+
+static __always_inline void
+default_libc_feresetround_ctx (struct rm_ctx *ctx)
+{
+  /* Restore the rounding mode if updated.  */
+  if (unlikely (ctx->updated_status))
+    feupdateenv (&ctx->env);
+}
+
+static __always_inline void
+default_libc_feholdsetround_noex_ctx (struct rm_ctx *ctx, int round)
+{
+  /* Save exception flags and rounding mode, and disable exception
+     traps.  */
+  feholdexcept (&ctx->env);
+
+  /* Update rounding mode only if different.  */
+  if (unlikely (round != get_rounding_mode ()))
+    fesetround (round);
+}
+
+static __always_inline void
+default_libc_feresetround_noex_ctx (struct rm_ctx *ctx)
+{
+  /* Restore exception flags and rounding mode.  */
+  fesetenv (&ctx->env);
+}
+
+#if HAVE_RM_CTX
+/* Set/Restore Rounding Modes only when necessary.  If defined, these functions
+   set/restore floating point state only if the state needed within the lexical
+   block is different from the current state.  This saves a lot of time when
+   the floating point unit is much slower than the fixed point units.  */
+
+# ifndef libc_feholdsetround_noex_ctx
+#   define libc_feholdsetround_noex_ctx  libc_feholdsetround_ctx
+# endif
+# ifndef libc_feholdsetround_noexf_ctx
+#   define libc_feholdsetround_noexf_ctx libc_feholdsetroundf_ctx
+# endif
+# ifndef libc_feholdsetround_noexl_ctx
+#   define libc_feholdsetround_noexl_ctx libc_feholdsetroundl_ctx
+# endif
+
+# ifndef libc_feresetround_noex_ctx
+#   define libc_feresetround_noex_ctx  libc_fesetenv_ctx
+# endif
+# ifndef libc_feresetround_noexf_ctx
+#   define libc_feresetround_noexf_ctx libc_fesetenvf_ctx
+# endif
+# ifndef libc_feresetround_noexl_ctx
+#   define libc_feresetround_noexl_ctx libc_fesetenvl_ctx
+# endif
+
+#else
+
+# define libc_feholdsetround_ctx      default_libc_feholdsetround_ctx
+# define libc_feresetround_ctx        default_libc_feresetround_ctx
+# define libc_feholdsetround_noex_ctx default_libc_feholdsetround_noex_ctx
+# define libc_feresetround_noex_ctx   default_libc_feresetround_noex_ctx
+
+# define libc_feholdsetroundf_ctx libc_feholdsetround_ctx
+# define libc_feholdsetroundl_ctx libc_feholdsetround_ctx
+# define libc_feresetroundf_ctx   libc_feresetround_ctx
+# define libc_feresetroundl_ctx   libc_feresetround_ctx
+
+# define libc_feholdsetround_noexf_ctx libc_feholdsetround_noex_ctx
+# define libc_feholdsetround_noexl_ctx libc_feholdsetround_noex_ctx
+# define libc_feresetround_noexf_ctx   libc_feresetround_noex_ctx
+# define libc_feresetround_noexl_ctx   libc_feresetround_noex_ctx
+
+#endif
+
+#ifndef libc_feholdsetround_53bit_ctx
+#  define libc_feholdsetround_53bit_ctx libc_feholdsetround_ctx
+#endif
+#ifndef libc_feresetround_53bit_ctx
+#  define libc_feresetround_53bit_ctx libc_feresetround_ctx
+#endif
+
+#define SET_RESTORE_ROUND_GENERIC(RM,ROUNDFUNC,CLEANUPFUNC) \
+  struct rm_ctx ctx __attribute__((cleanup (CLEANUPFUNC ## _ctx))); \
+  ROUNDFUNC ## _ctx (&ctx, (RM))
+
+/* Set the rounding mode within a lexical block.  Restore the rounding mode to
+   the value at the start of the block.  The exception mode must be preserved.
+   Exceptions raised within the block must be set in the exception flags.
+   Non-stop mode may be enabled inside the block.  */
+
+#define SET_RESTORE_ROUND(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetround, libc_feresetround)
+#define SET_RESTORE_ROUNDF(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetroundf, libc_feresetroundf)
+#define SET_RESTORE_ROUNDL(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetroundl, libc_feresetroundl)
+
+/* Set the rounding mode within a lexical block.  Restore the rounding mode to
+   the value at the start of the block.  The exception mode must be preserved.
+   Exceptions raised within the block must be discarded, and exception flags
+   are restored to the value at the start of the block.
+   Non-stop mode must be enabled inside the block.  */
+
+#define SET_RESTORE_ROUND_NOEX(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetround_noex, \
+			     libc_feresetround_noex)
+#define SET_RESTORE_ROUND_NOEXF(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetround_noexf, \
+			     libc_feresetround_noexf)
+#define SET_RESTORE_ROUND_NOEXL(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetround_noexl, \
+			     libc_feresetround_noexl)
+
+/* Like SET_RESTORE_ROUND, but also set rounding precision to 53 bits.  */
+#define SET_RESTORE_ROUND_53BIT(RM) \
+  SET_RESTORE_ROUND_GENERIC (RM, libc_feholdsetround_53bit,	      \
+			     libc_feresetround_53bit)
+
+#endif /* fenv_private.h.  */

libm/arc/fesetenv.c

@@ -0,0 +1,44 @@
+/* Install given floating-point environment (does not raise exceptions).
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fpu_control.h"
+
+int
+fesetenv (const fenv_t *envp)
+{
+  unsigned int fpcr;
+  unsigned int fpsr;
+
+  if (envp == FE_DFL_ENV)
+    {
+      fpcr = _FPU_DEFAULT;
+      fpsr = _FPU_FPSR_DEFAULT;
+    }
+  else
+    {
+      /* No need to mask out reserved bits as they are IoW.  */
+      fpcr = envp->__fpcr;
+      fpsr = envp->__fpsr;
+    }
+
+  _FPU_SETCW (fpcr);
+  _FPU_SETS (fpsr);
+
+  /* Success.  */
+  return 0;
+}

libm/arc/fesetexcept.c

@@ -0,0 +1,31 @@
+/* Set given exception flags.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fpu_control.h"
+
+int
+fesetexcept (int excepts)
+{
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+  fpsr |= excepts;
+  _FPU_SETS (fpsr);
+
+  return 0;
+}

libm/arc/fesetmode.c

@@ -0,0 +1,39 @@
+/* Install given floating-point control modes.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fpu_control.h"
+
+int
+fesetmode (const femode_t *modep)
+{
+  unsigned int fpcr;
+
+  if (modep == FE_DFL_MODE)
+    {
+      fpcr = _FPU_DEFAULT;
+    }
+  else
+    {
+      /* No need to mask out reserved bits as they are IoW.  */
+      fpcr = *modep;
+    }
+
+  _FPU_SETCW (fpcr);
+
+  return 0;
+}

libm/arc/fesetround.c

@@ -0,0 +1,36 @@
+/* Set current rounding direction.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fenv_private.h"
+
+int
+fesetround (int round)
+{
+  unsigned int fpcr;
+
+  _FPU_GETCW (fpcr);
+
+  if (((fpcr >> __FPU_RND_SHIFT) & __FPU_RND_MASK) != round)
+    {
+      fpcr &= ~(__FPU_RND_MASK << __FPU_RND_SHIFT);
+      fpcr |= (round & __FPU_RND_MASK) << __FPU_RND_SHIFT;
+      _FPU_SETCW (fpcr);
+    }
+
+  return 0;
+}

libm/arc/feupdateenv.c

@@ -0,0 +1,47 @@
+/* Install given floating-point environment and raise exceptions,
+   without clearing currently raised exceptions.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fpu_control.h"
+
+int
+feupdateenv (const fenv_t *envp)
+{
+  unsigned int fpcr;
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+
+  if (envp == FE_DFL_ENV)
+    {
+      fpcr = _FPU_DEFAULT;
+    }
+  else
+    {
+      fpcr = envp->__fpcr;
+
+      /* currently raised exceptions need to be preserved.  */
+      fpsr |= envp->__fpsr;
+    }
+
+  _FPU_SETCW (fpcr);
+  _FPU_SETS (fpsr);
+
+  /* Success.  */
+  return 0;
+}

libm/arc/fgetexcptflg.c

@@ -0,0 +1,30 @@
+/* Store current representation for exceptions, ARC version.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include "fenv_private.h"
+
+int
+fegetexceptflag (fexcept_t *flagp, int excepts)
+{
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+  *flagp = fpsr & excepts;
+
+  return 0;
+}

libm/arc/fraiseexcpt.c

@@ -0,0 +1,35 @@
+/* Raise given exceptions.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+#include <float.h>
+#include <math.h>
+
+int
+feraiseexcept (int excepts)
+{
+  unsigned int fpsr;
+
+  /* currently raised exceptions are not cleared.  */
+  _FPU_GETS (fpsr);
+  fpsr |= excepts;
+
+  _FPU_SETS (fpsr);
+
+  return 0;
+}

libm/arc/fsetexcptflg.c

@@ -0,0 +1,37 @@
+/* Set floating-point environment exception handling, ARC version.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+
+int
+fesetexceptflag (const fexcept_t *flagp, int excepts)
+{
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+
+  /* Clear the bits first.  */
+  fpsr &= ~excepts;
+
+  /* Now set those bits, copying them over from @flagp.  */
+  fpsr |= *flagp & excepts;
+
+  _FPU_SETS (fpsr);
+
+  return 0;
+}

libm/arc/ftestexcept.c

@@ -0,0 +1,31 @@
+/* Test exception in current environment.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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 <fenv.h>
+#include <fpu_control.h>
+#include "fenv_private.h"
+#include <stdio.h>
+
+int
+fetestexcept (int excepts)
+{
+  unsigned int fpsr;
+
+  _FPU_GETS (fpsr);
+
+  return fpsr & excepts;
+}

libm/arc/get-rounding-mode.h

@@ -0,0 +1,37 @@
+/* Determine floating-point rounding mode within libc.  ARC version.
+   Copyright (C) 2020-2025 Free Software Foundation, Inc.
+
+   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/>.  */
+
+#ifndef _ARC_GET_ROUNDING_MODE_H
+#define _ARC_GET_ROUNDING_MODE_H	1
+
+#include <fenv.h>
+#include <fpu_control.h>
+
+static inline int
+get_rounding_mode (void)
+{
+#if defined(__ARC_FPU_SP__) ||  defined(__ARC_FPU_DP__)
+  unsigned int fpcr;
+  _FPU_GETCW (fpcr);
+
+  return (fpcr >> __FPU_RND_SHIFT) & __FPU_RND_MASK;
+#else
+  return FE_TONEAREST;
+#endif
+}
+
+#endif /* get-rounding-mode.h */