aarch64: add fenv support from glibc

extra/Configs/Config.in.arch

@@ -164,6 +164,7 @@ config UCLIBC_HAS_FENV
 	bool "Enable C99 Floating-point environment"
 	depends on UCLIBC_HAS_FLOATS
 	depends on TARGET_i386 || \
+		   TARGET_aarch64 || \
 		   TARGET_metag || \
 		   TARGET_nds32 || \
 		   (TARGET_powerpc && CONFIG_E500) || \

include/fenv.h

@@ -23,6 +23,7 @@
 #define _FENV_H	1
 
 #include <features.h>
+#include <stdbool.h>
 
 /* Get the architecture dependend definitions.  The following definitions
    are expected to be done:
@@ -130,6 +131,15 @@ extern int fedisableexcept (int __excepts) __THROW;
 extern int fegetexcept (void) __THROW;
 #endif
 
+/* Rounding mode context.  This allows functions to set/restore rounding mode
+   only when the desired rounding mode is different from the current rounding
+   mode.  */
+struct rm_ctx
+{
+  fenv_t env;
+  bool updated_status;
+};
+
 __END_DECLS
 
 #endif /* fenv.h */

libc/sysdeps/linux/aarch64/bits/fenv.h

@@ -0,0 +1,78 @@
+/* Copyright (C) 2004-2025 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_H
+# error "Never use <bits/fenv.h> directly; include <fenv.h> instead."
+#endif
+
+/* Define bits representing exceptions in the FPSR status word.  */
+enum
+  {
+    FE_INVALID =
+#define FE_INVALID	1
+      FE_INVALID,
+    FE_DIVBYZERO =
+#define FE_DIVBYZERO	2
+      FE_DIVBYZERO,
+    FE_OVERFLOW =
+#define FE_OVERFLOW	4
+      FE_OVERFLOW,
+    FE_UNDERFLOW =
+#define FE_UNDERFLOW	8
+      FE_UNDERFLOW,
+    FE_INEXACT =
+#define FE_INEXACT	16
+      FE_INEXACT,
+  };
+
+/* Amount to shift by to convert an exception bit in FPSR to a an
+   exception bit mask in FPCR.  */
+#define FE_EXCEPT_SHIFT	8
+
+/* All supported exceptions.  */
+#define FE_ALL_EXCEPT	\
+	(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW | FE_INEXACT)
+
+/* Define bits representing rounding modes in the FPCR Rmode field.  */
+#define FE_TONEAREST  0x000000
+#define FE_UPWARD     0x400000
+#define FE_DOWNWARD   0x800000
+#define FE_TOWARDZERO 0xc00000
+
+/* Type representing exception flags. */
+typedef unsigned int fexcept_t;
+
+/* Type representing floating-point environment.  */
+typedef struct
+  {
+    unsigned int __fpcr;
+    unsigned int __fpsr;
+  }
+fenv_t;
+
+/* If the default argument is used we use this value.  */
+#define FE_DFL_ENV	((const fenv_t *) -1l)
+
+#ifdef __USE_GNU
+/* Floating-point environment where none of the exceptions are masked.  */
+# define FE_NOMASK_ENV  ((const fenv_t *) -2)
+#endif
+
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)

libc/sysdeps/linux/aarch64/fpu_control.h

@@ -0,0 +1,102 @@
+/* Copyright (C) 1996-2025 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 _AARCH64_FPU_CONTROL_H
+#define _AARCH64_FPU_CONTROL_H
+
+#include <features.h>
+
+/* Macros for accessing the FPCR and FPSR.  */
+
+#if __GNUC_PREREQ (6,0)
+# define _FPU_GETCW(fpcr) (fpcr = __builtin_aarch64_get_fpcr ())
+# define _FPU_SETCW(fpcr) __builtin_aarch64_set_fpcr (fpcr)
+# define _FPU_GETFPSR(fpsr) (fpsr = __builtin_aarch64_get_fpsr ())
+# define _FPU_SETFPSR(fpsr) __builtin_aarch64_set_fpsr (fpsr)
+#else
+# define _FPU_GETCW(fpcr)					\
+  ({ 								\
+   __uint64_t __fpcr;						\
+   __asm__ __volatile__ ("mrs	%0, fpcr" : "=r" (__fpcr));	\
+   fpcr = __fpcr;						\
+  })
+
+# define _FPU_SETCW(fpcr)					\
+  ({								\
+   __uint64_t __fpcr = fpcr;					\
+   __asm__ __volatile__ ("msr	fpcr, %0" : : "r" (__fpcr));    \
+  })
+
+# define _FPU_GETFPSR(fpsr)					\
+  ({								\
+   __uint64_t __fpsr;						\
+   __asm__ __volatile__ ("mrs	%0, fpsr" : "=r" (__fpsr));	\
+   fpsr = __fpsr;						\
+  })
+
+# define _FPU_SETFPSR(fpsr)					\
+  ({								\
+   __uint64_t __fpsr = fpsr;					\
+   __asm__ __volatile__ ("msr	fpsr, %0" : : "r" (__fpsr));    \
+  })
+#endif
+
+/* Reserved bits should be preserved when modifying register
+   contents. These two masks indicate which bits in each of FPCR and
+   FPSR should not be changed.  */
+
+#define _FPU_RESERVED		0xfe0fe0f8
+#define _FPU_FPSR_RESERVED	0x0fffffe0
+
+#define _FPU_DEFAULT		0x00000000
+#define _FPU_FPSR_DEFAULT	0x00000000
+
+/* Layout of FPCR and FPSR:
+
+   |       |       |       |       |       |       |       |
+   0 0 0 0 1 1 1 0 0 0 0 0 1 0 0 0 1 1 1 0 0 0 0 0 1 1 1 0 0 0 0 0
+   s s s s s                                       s     s s s s s
+             c c c c c c c               c c c c c
+   N Z C V Q A D F R R S S S L L L I U U I U O D I I U U I U O D I
+           C H N Z M M T T B E E E D N N X F F Z O D N N X F F Z O
+             P     O O R R Z N N N E K K E E E E E C K K C C C C C
+                   D D I I P
+                   E E D D
+                       E E
+ */
+
+#define _FPU_FPCR_RM_MASK  0xc00000
+
+#define _FPU_FPCR_MASK_IXE 0x1000
+#define _FPU_FPCR_MASK_UFE 0x0800
+#define _FPU_FPCR_MASK_OFE 0x0400
+#define _FPU_FPCR_MASK_DZE 0x0200
+#define _FPU_FPCR_MASK_IOE 0x0100
+
+#define _FPU_FPCR_IEEE                       \
+  (_FPU_DEFAULT  | _FPU_FPCR_MASK_IXE	     \
+   | _FPU_FPCR_MASK_UFE | _FPU_FPCR_MASK_OFE \
+   | _FPU_FPCR_MASK_DZE | _FPU_FPCR_MASK_IOE)
+
+#define _FPU_FPSR_IEEE 0
+
+typedef unsigned int fpu_control_t;
+typedef unsigned int fpu_fpsr_t;
+
+/* Default control word set at startup.  */
+extern fpu_control_t __fpu_control;
+
+#endif

libm/aarch64/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/aarch64/fclrexcpt.c

@@ -0,0 +1,35 @@
+/* Copyright (C) 1997-2025 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)
+{
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t fpsr_new;
+
+  excepts &= FE_ALL_EXCEPT;
+
+  _FPU_GETFPSR (fpsr);
+  fpsr_new = fpsr & ~excepts;
+
+  if (fpsr != fpsr_new)
+    _FPU_SETFPSR (fpsr_new);
+
+  return 0;
+}

libm/aarch64/fedisblxcpt.c

@@ -0,0 +1,34 @@
+/* Copyright (C) 2001-2025 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
+fedisableexcept (int excepts)
+{
+  fpu_control_t fpcr;
+  fpu_control_t fpcr_new;
+
+  _FPU_GETCW (fpcr);
+  excepts &= FE_ALL_EXCEPT;
+  fpcr_new = fpcr & ~(excepts << FE_EXCEPT_SHIFT);
+
+  if (fpcr != fpcr_new)
+    _FPU_SETCW (fpcr_new);
+
+  return (fpcr >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
+}

libm/aarch64/feenablxcpt.c

@@ -0,0 +1,45 @@
+/* Copyright (C) 2001-2025 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
+feenableexcept (int excepts)
+{
+  fpu_control_t fpcr;
+  fpu_control_t fpcr_new;
+  fpu_control_t updated_fpcr;
+
+  _FPU_GETCW (fpcr);
+  excepts &= FE_ALL_EXCEPT;
+  fpcr_new = fpcr | (excepts << FE_EXCEPT_SHIFT);
+
+  if (fpcr != fpcr_new)
+    {
+      _FPU_SETCW (fpcr_new);
+
+      /* Trapping exceptions are optional in AArch64; the relevant enable
+	 bits in FPCR are RES0 hence the absence of support can be detected
+	 by reading back the FPCR and comparing with the required value.  */
+      _FPU_GETCW (updated_fpcr);
+
+      if (fpcr_new & ~updated_fpcr)
+	return -1;
+    }
+
+  return (fpcr >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
+}

libm/aarch64/fegetenv.c

@@ -0,0 +1,30 @@
+/* Copyright (C) 1997-2025 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)
+{
+  fpu_control_t fpcr;
+  fpu_fpsr_t fpsr;
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+  return 0;
+}

libm/aarch64/fegetexcept.c

@@ -0,0 +1,26 @@
+/* Copyright (C) 2001-2025 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
+fegetexcept (void)
+{
+  fpu_control_t fpcr;
+  _FPU_GETCW (fpcr);
+  return (fpcr >> FE_EXCEPT_SHIFT) & FE_ALL_EXCEPT;
+}

libm/aarch64/fegetmode.c

@@ -0,0 +1,26 @@
+/* Store current floating-point control modes.  AArch64 version.
+   Copyright (C) 2016-2025 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)
+{
+  _FPU_GETCW (*modep);
+  return 0;
+}

libm/aarch64/fegetround.c

@@ -0,0 +1,35 @@
+/* Copyright (C) 1997-2025 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>
+
+/* Return the floating-point rounding mode.  */
+
+static inline int
+get_rounding_mode (void)
+{
+  fpu_control_t fpcr;
+
+  _FPU_GETCW (fpcr);
+  return fpcr & _FPU_FPCR_RM_MASK;
+}
+
+int
+fegetround (void)
+{
+  return get_rounding_mode ();
+}

libm/aarch64/feholdexcpt.c

@@ -0,0 +1,25 @@
+/* Copyright (C) 1997-2025 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)
+{
+  libc_feholdexcept_aarch64 (envp);
+  return 0;
+}

libm/aarch64/fenv_private.h

@@ -0,0 +1,300 @@
+/* Private floating point rounding and exceptions handling.  AArch64 version.
+   Copyright (C) 2014-2025 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 AARCH64_FENV_PRIVATE_H
+#define AARCH64_FENV_PRIVATE_H 1
+
+#include <fenv.h>
+#include <fpu_control.h>
+
+static __always_inline void
+libc_feholdexcept_aarch64 (fenv_t *envp)
+{
+  fpu_control_t fpcr;
+  fpu_control_t new_fpcr;
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t new_fpsr;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+
+  /* Clear exception flags and set all exceptions to non-stop.  */
+  new_fpcr = fpcr & ~(FE_ALL_EXCEPT << FE_EXCEPT_SHIFT);
+  new_fpsr = fpsr & ~FE_ALL_EXCEPT;
+
+  if (unlikely (new_fpcr != fpcr))
+    _FPU_SETCW (new_fpcr);
+
+  if (new_fpsr != fpsr)
+    _FPU_SETFPSR (new_fpsr);
+}
+
+#define libc_feholdexcept  libc_feholdexcept_aarch64
+#define libc_feholdexceptf libc_feholdexcept_aarch64
+#define libc_feholdexceptl libc_feholdexcept_aarch64
+
+static __always_inline void
+libc_fesetround_aarch64 (int round)
+{
+  fpu_control_t fpcr;
+
+  _FPU_GETCW (fpcr);
+
+  /* Check whether rounding modes are different.  */
+  round = (fpcr ^ round) & _FPU_FPCR_RM_MASK;
+
+  /* Set new rounding mode if different.  */
+  if (unlikely (round != 0))
+    _FPU_SETCW (fpcr ^ round);
+}
+
+#define libc_fesetround  libc_fesetround_aarch64
+#define libc_fesetroundf libc_fesetround_aarch64
+#define libc_fesetroundl libc_fesetround_aarch64
+
+static __always_inline void
+libc_feholdexcept_setround_aarch64 (fenv_t *envp, int round)
+{
+  fpu_control_t fpcr;
+  fpu_control_t new_fpcr;
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t new_fpsr;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+
+  /* Clear exception flags, set all exceptions to non-stop,
+     and set new rounding mode.  */
+  new_fpcr = fpcr & ~((FE_ALL_EXCEPT << FE_EXCEPT_SHIFT) | _FPU_FPCR_RM_MASK);
+  new_fpcr |= round;
+  new_fpsr = fpsr & ~FE_ALL_EXCEPT;
+
+  if (unlikely (new_fpcr != fpcr))
+    _FPU_SETCW (new_fpcr);
+
+  if (new_fpsr != fpsr)
+    _FPU_SETFPSR (new_fpsr);
+}
+
+#define libc_feholdexcept_setround  libc_feholdexcept_setround_aarch64
+#define libc_feholdexcept_setroundf libc_feholdexcept_setround_aarch64
+#define libc_feholdexcept_setroundl libc_feholdexcept_setround_aarch64
+
+static __always_inline int
+libc_fetestexcept_aarch64 (int ex)
+{
+  fpu_fpsr_t fpsr;
+
+  _FPU_GETFPSR (fpsr);
+  return fpsr & ex & FE_ALL_EXCEPT;
+}
+
+#define libc_fetestexcept  libc_fetestexcept_aarch64
+#define libc_fetestexceptf libc_fetestexcept_aarch64
+#define libc_fetestexceptl libc_fetestexcept_aarch64
+
+static __always_inline void
+libc_fesetenv_aarch64 (const fenv_t *envp)
+{
+  fpu_control_t fpcr;
+  fpu_control_t new_fpcr;
+
+  _FPU_GETCW (fpcr);
+  new_fpcr = envp->__fpcr;
+
+  if (unlikely (fpcr != new_fpcr))
+    _FPU_SETCW (new_fpcr);
+
+  _FPU_SETFPSR (envp->__fpsr);
+}
+
+#define libc_fesetenv  libc_fesetenv_aarch64
+#define libc_fesetenvf libc_fesetenv_aarch64
+#define libc_fesetenvl libc_fesetenv_aarch64
+#define libc_feresetround_noex  libc_fesetenv_aarch64
+#define libc_feresetround_noexf libc_fesetenv_aarch64
+#define libc_feresetround_noexl libc_fesetenv_aarch64
+
+static __always_inline int
+libc_feupdateenv_test_aarch64 (const fenv_t *envp, int ex)
+{
+  fpu_control_t fpcr;
+  fpu_control_t new_fpcr;
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t new_fpsr;
+  int excepts;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+
+  /* Merge current exception flags with the saved fenv.  */
+  excepts = fpsr & FE_ALL_EXCEPT;
+  new_fpcr = envp->__fpcr;
+  new_fpsr = envp->__fpsr | excepts;
+
+  if (unlikely (fpcr != new_fpcr))
+    _FPU_SETCW (new_fpcr);
+
+  if (fpsr != new_fpsr)
+    _FPU_SETFPSR (new_fpsr);
+
+  /* Raise the exceptions if enabled in the new FP state.  */
+  if (unlikely (excepts & (new_fpcr >> FE_EXCEPT_SHIFT)))
+    feraiseexcept (excepts);
+
+  return excepts & ex;
+}
+
+#define libc_feupdateenv_test  libc_feupdateenv_test_aarch64
+#define libc_feupdateenv_testf libc_feupdateenv_test_aarch64
+#define libc_feupdateenv_testl libc_feupdateenv_test_aarch64
+
+static __always_inline void
+libc_feupdateenv_aarch64 (const fenv_t *envp)
+{
+  libc_feupdateenv_test_aarch64 (envp, 0);
+}
+
+#define libc_feupdateenv  libc_feupdateenv_aarch64
+#define libc_feupdateenvf libc_feupdateenv_aarch64
+#define libc_feupdateenvl libc_feupdateenv_aarch64
+
+static __always_inline void
+libc_feholdsetround_aarch64 (fenv_t *envp, int round)
+{
+  fpu_control_t fpcr;
+  fpu_fpsr_t fpsr;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  envp->__fpcr = fpcr;
+  envp->__fpsr = fpsr;
+
+  /* Check whether rounding modes are different.  */
+  round = (fpcr ^ round) & _FPU_FPCR_RM_MASK;
+
+  /* Set new rounding mode if different.  */
+  if (unlikely (round != 0))
+    _FPU_SETCW (fpcr ^ round);
+}
+
+#define libc_feholdsetround  libc_feholdsetround_aarch64
+#define libc_feholdsetroundf libc_feholdsetround_aarch64
+#define libc_feholdsetroundl libc_feholdsetround_aarch64
+
+static __always_inline void
+libc_feresetround_aarch64 (fenv_t *envp)
+{
+  fpu_control_t fpcr;
+  int round;
+
+  _FPU_GETCW (fpcr);
+
+  /* Check whether rounding modes are different.  */
+  round = (envp->__fpcr ^ fpcr) & _FPU_FPCR_RM_MASK;
+
+  /* Restore the rounding mode if it was changed.  */
+  if (unlikely (round != 0))
+    _FPU_SETCW (fpcr ^ round);
+}
+
+#define libc_feresetround  libc_feresetround_aarch64
+#define libc_feresetroundf libc_feresetround_aarch64
+#define libc_feresetroundl libc_feresetround_aarch64
+
+/* We have support for rounding mode context.  */
+#define HAVE_RM_CTX 1
+
+static __always_inline void
+libc_feholdsetround_aarch64_ctx (struct rm_ctx *ctx, int r)
+{
+  fpu_control_t fpcr;
+  int round;
+
+  _FPU_GETCW (fpcr);
+  ctx->env.__fpcr = fpcr;
+
+  /* Check whether rounding modes are different.  */
+  round = (fpcr ^ r) & _FPU_FPCR_RM_MASK;
+  ctx->updated_status = round != 0;
+
+  /* Set the rounding mode if changed.  */
+  if (unlikely (round != 0))
+    _FPU_SETCW (fpcr ^ round);
+}
+
+#define libc_feholdsetround_ctx		libc_feholdsetround_aarch64_ctx
+#define libc_feholdsetroundf_ctx	libc_feholdsetround_aarch64_ctx
+#define libc_feholdsetroundl_ctx	libc_feholdsetround_aarch64_ctx
+
+static __always_inline void
+libc_feresetround_aarch64_ctx (struct rm_ctx *ctx)
+{
+  /* Restore the rounding mode if updated.  */
+  if (unlikely (ctx->updated_status))
+    _FPU_SETCW (ctx->env.__fpcr);
+}
+
+#define libc_feresetround_ctx		libc_feresetround_aarch64_ctx
+#define libc_feresetroundf_ctx		libc_feresetround_aarch64_ctx
+#define libc_feresetroundl_ctx		libc_feresetround_aarch64_ctx
+
+static __always_inline void
+libc_feholdsetround_noex_aarch64_ctx (struct rm_ctx *ctx, int r)
+{
+  fpu_control_t fpcr;
+  fpu_fpsr_t fpsr;
+  int round;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  ctx->env.__fpcr = fpcr;
+  ctx->env.__fpsr = fpsr;
+
+  /* Check whether rounding modes are different.  */
+  round = (fpcr ^ r) & _FPU_FPCR_RM_MASK;
+  ctx->updated_status = round != 0;
+
+  /* Set the rounding mode if changed.  */
+  if (unlikely (round != 0))
+    _FPU_SETCW (fpcr ^ round);
+}
+
+#define libc_feholdsetround_noex_ctx	libc_feholdsetround_noex_aarch64_ctx
+#define libc_feholdsetround_noexf_ctx	libc_feholdsetround_noex_aarch64_ctx
+#define libc_feholdsetround_noexl_ctx	libc_feholdsetround_noex_aarch64_ctx
+
+static __always_inline void
+libc_feresetround_noex_aarch64_ctx (struct rm_ctx *ctx)
+{
+  /* Restore the rounding mode if updated.  */
+  if (unlikely (ctx->updated_status))
+    _FPU_SETCW (ctx->env.__fpcr);
+
+  /* Write new FPSR to restore exception flags.  */
+  _FPU_SETFPSR (ctx->env.__fpsr);
+}
+
+#define libc_feresetround_noex_ctx	libc_feresetround_noex_aarch64_ctx
+#define libc_feresetround_noexf_ctx	libc_feresetround_noex_aarch64_ctx
+#define libc_feresetround_noexl_ctx	libc_feresetround_noex_aarch64_ctx
+
+#endif

libm/aarch64/fesetenv.c

@@ -0,0 +1,73 @@
+/* Copyright (C) 1997-2025 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)
+{
+  fpu_control_t fpcr;
+  fpu_control_t fpcr_new;
+  fpu_control_t updated_fpcr;
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t fpsr_new;
+
+  _FPU_GETCW (fpcr);
+
+  if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
+    {
+      /* The new FPCR/FPSR are valid, so don't merge the reserved flags.  */
+      fpcr_new = envp->__fpcr;
+
+      if (fpcr != fpcr_new)
+	_FPU_SETCW (fpcr_new);
+
+      _FPU_SETFPSR (envp->__fpsr);
+      return 0;
+    }
+
+  _FPU_GETFPSR (fpsr);
+  fpcr_new = fpcr & _FPU_RESERVED;
+  fpsr_new = fpsr & _FPU_FPSR_RESERVED;
+
+  if (envp == FE_DFL_ENV)
+    {
+      fpcr_new |= _FPU_DEFAULT;
+      fpsr_new |= _FPU_FPSR_DEFAULT;
+    }
+  else
+    {
+      fpcr_new |= _FPU_FPCR_IEEE;
+      fpsr_new |= _FPU_FPSR_IEEE;
+    }
+
+  _FPU_SETFPSR (fpsr_new);
+
+  if (fpcr != fpcr_new)
+    {
+      _FPU_SETCW (fpcr_new);
+
+      /* Trapping exceptions are optional in AArch64; the relevant enable
+	 bits in FPCR are RES0 hence the absence of support can be detected
+	 by reading back the FPCR and comparing with the required value.  */
+      _FPU_GETCW (updated_fpcr);
+
+      return fpcr_new & ~updated_fpcr;
+    }
+
+  return 0;
+}

libm/aarch64/fesetexcept.c

@@ -0,0 +1,33 @@
+/* Set given exception flags.  AArch64 version.
+   Copyright (C) 2016-2025 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)
+{
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t fpsr_new;
+
+  _FPU_GETFPSR (fpsr);
+  fpsr_new = fpsr | (excepts & FE_ALL_EXCEPT);
+  if (fpsr != fpsr_new)
+    _FPU_SETFPSR (fpsr_new);
+
+  return 0;
+}

libm/aarch64/fesetmode.c

@@ -0,0 +1,33 @@
+/* Install given floating-point control modes.  AArch64 version.
+   Copyright (C) 2016-2025 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)
+{
+  fpu_control_t fpcr, fpcr_new;
+  _FPU_GETCW (fpcr);
+  if (modep == FE_DFL_MODE)
+    fpcr_new = (fpcr & _FPU_RESERVED) | _FPU_DEFAULT;
+  else
+    fpcr_new = *modep;
+  if (fpcr != fpcr_new)
+    _FPU_SETCW (fpcr_new);
+  return 0;
+}

libm/aarch64/fesetround.c

@@ -0,0 +1,29 @@
+/* Copyright (C) 1997-2025 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"
+#include <fpu_control.h>
+
+int
+fesetround (int round)
+{
+  if (round & ~_FPU_FPCR_RM_MASK)
+    return 1;
+
+  libc_fesetround_aarch64 (round);
+  return 0;
+}

libm/aarch64/feupdateenv.c

@@ -0,0 +1,84 @@
+/* Copyright (C) 2009-2025 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)
+{
+  fpu_control_t fpcr;
+  fpu_control_t fpcr_new;
+  fpu_control_t updated_fpcr;
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t fpsr_new;
+  int excepts;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+  excepts = fpsr & FE_ALL_EXCEPT;
+
+  if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
+    {
+      fpcr_new = envp->__fpcr;
+      fpsr_new = envp->__fpsr | excepts;
+
+      if (fpcr != fpcr_new)
+        _FPU_SETCW (fpcr_new);
+
+      if (fpsr != fpsr_new)
+        _FPU_SETFPSR (fpsr_new);
+
+      if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT))
+        return feraiseexcept (excepts);
+
+      return 0;
+    }
+
+  fpcr_new = fpcr & _FPU_RESERVED;
+  fpsr_new = fpsr & (_FPU_FPSR_RESERVED | FE_ALL_EXCEPT);
+
+  if (envp == FE_DFL_ENV)
+    {
+      fpcr_new |= _FPU_DEFAULT;
+      fpsr_new |= _FPU_FPSR_DEFAULT;
+    }
+  else
+    {
+      fpcr_new |= _FPU_FPCR_IEEE;
+      fpsr_new |= _FPU_FPSR_IEEE;
+    }
+
+  _FPU_SETFPSR (fpsr_new);
+
+  if (fpcr != fpcr_new)
+    {
+      _FPU_SETCW (fpcr_new);
+
+      /* Trapping exceptions are optional in AArch64; the relevant enable
+	 bits in FPCR are RES0 hence the absence of support can be detected
+	 by reading back the FPCR and comparing with the required value.  */
+      _FPU_GETCW (updated_fpcr);
+
+      if (fpcr_new & ~updated_fpcr)
+        return 1;
+    }
+
+  if (excepts & (fpcr_new >> FE_EXCEPT_SHIFT))
+    return feraiseexcept (excepts);
+
+  return 0;
+}

libm/aarch64/fgetexcptflg.c

@@ -0,0 +1,25 @@
+/* Copyright (C) 2001-2025 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)
+{
+  *flagp = libc_fetestexcept_aarch64 (excepts);
+  return 0;
+}

libm/aarch64/fraiseexcpt.c

@@ -0,0 +1,89 @@
+/* Copyright (C) 1997-2025 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 <stdint.h>
+
+int
+feraiseexcept (int excepts)
+{
+  uint64_t fpsr;
+  const float fp_zero = 0.0;
+  const float fp_one = 1.0;
+  const float fp_max = FLT_MAX;
+  const float fp_min = FLT_MIN;
+  const float fp_1e32 = 1.0e32f;
+  const float fp_two = 2.0;
+  const float fp_three = 3.0;
+
+  /* Raise exceptions represented by EXCEPTS.  But we must raise only
+     one signal at a time.  It is important that if the OVERFLOW or
+     UNDERFLOW exception and the inexact exception are given at the
+     same time, the OVERFLOW or UNDERFLOW exception precedes the
+     INEXACT exception.
+
+     After each exception we read from the FPSR, to force the
+     exception to be raised immediately.  */
+
+  if (FE_INVALID & excepts)
+    __asm__ __volatile__ (
+			  "ldr	s0, %1\n\t"
+			  "fdiv	s0, s0, s0\n\t"
+			  "mrs	%0, fpsr" : "=r" (fpsr)
+			  : "m" (fp_zero)
+			  : "d0");
+
+  if (FE_DIVBYZERO & excepts)
+    __asm__ __volatile__ (
+			  "ldr	s0, %1\n\t"
+			  "ldr	s1, %2\n\t"
+			  "fdiv	s0, s0, s1\n\t"
+			  "mrs	%0, fpsr" : "=r" (fpsr)
+			  : "m" (fp_one), "m" (fp_zero)
+			  : "d0", "d1");
+
+  if (FE_OVERFLOW & excepts)
+    /* There's no way to raise overflow without also raising inexact.  */
+    __asm__ __volatile__ (
+			  "ldr	s0, %1\n\t"
+			  "ldr	s1, %2\n\t"
+			  "fadd s0, s0, s1\n\t"
+			  "mrs	%0, fpsr" : "=r" (fpsr)
+			  : "m" (fp_max), "m" (fp_1e32)
+			  : "d0", "d1");
+
+  if (FE_UNDERFLOW & excepts)
+    __asm__ __volatile__ (
+			  "ldr	s0, %1\n\t"
+			  "ldr	s1, %2\n\t"
+			  "fdiv s0, s0, s1\n\t"
+			  "mrs	%0, fpsr" : "=r" (fpsr)
+			  : "m" (fp_min), "m" (fp_three)
+			  : "d0", "d1");
+
+  if (FE_INEXACT & excepts)
+    __asm__ __volatile__ (
+			  "ldr	s0, %1\n\t"
+			  "ldr	s1, %2\n\t"
+			  "fdiv s0, s0, s1\n\t"
+			  "mrs	%0, fpsr" : "=r" (fpsr)
+			  : "m" (fp_two), "m" (fp_three)
+			  : "d0", "d1");
+
+  return 0;
+}

libm/aarch64/fsetexcptflg.c

@@ -0,0 +1,39 @@
+/* Copyright (C) 1997-2025 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)
+{
+  fpu_fpsr_t fpsr;
+  fpu_fpsr_t fpsr_new;
+
+  /* Get the current environment.  */
+  _FPU_GETFPSR (fpsr);
+  excepts &= FE_ALL_EXCEPT;
+
+  /* Set the desired exception mask.  */
+  fpsr_new = fpsr & ~excepts;
+  fpsr_new |= *flagp & excepts;
+
+  /* Save state back to the FPU.  */
+  if (fpsr != fpsr_new)
+    _FPU_SETFPSR (fpsr_new);
+
+  return 0;
+}

libm/aarch64/ftestexcept.c

@@ -0,0 +1,24 @@
+/* Copyright (C) 1997-2025 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
+fetestexcept (int excepts)
+{
+  return libc_fetestexcept_aarch64 (excepts);
+}