1 files changed, 73 insertions, 0 deletions
diff --git a/libm/arm/feupdateenv.c b/libm/arm/feupdateenv.c
new file mode 100644
index 000000000..a246b865b
--- /dev/null
+++ b/libm/arm/feupdateenv.c
@@ -0,0 +1,73 @@
+/* Install given floating-point environment and raise exceptions.
+   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 "arm-features.h"
+
+
+int
+feupdateenv (const fenv_t *envp)
+{
+  fpu_control_t fpscr, new_fpscr, updated_fpscr;
+  int excepts;
+
+  /* Fail if a VFP unit isn't present.  */
+  if (!ARM_HAVE_VFP)
+    return 1;
+
+  _FPU_GETCW (fpscr);
+  excepts = fpscr & FE_ALL_EXCEPT;
+
+  if ((envp != FE_DFL_ENV) && (envp != FE_NOMASK_ENV))
+    {
+      /* Merge current exception flags with the saved fenv.  */
+      new_fpscr = envp->__cw | excepts;
+
+      /* Write new FPSCR if different (ignoring NZCV flags).  */
+      if (((fpscr ^ new_fpscr) & ~_FPU_MASK_NZCV) != 0)
+	_FPU_SETCW (new_fpscr);
+
+      /* Raise the exceptions if enabled in the new FP state.  */
+      if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
+	return feraiseexcept (excepts);
+
+      return 0;
+    }
+
+  /* Preserve the reserved FPSCR flags.  */
+  new_fpscr = fpscr & (_FPU_RESERVED | FE_ALL_EXCEPT);
+  new_fpscr |= (envp == FE_DFL_ENV) ? _FPU_DEFAULT : _FPU_IEEE;
+
+  if (((new_fpscr ^ fpscr) & ~_FPU_MASK_NZCV) != 0)
+    {
+      _FPU_SETCW (new_fpscr);
+
+      /* Not all VFP architectures support trapping exceptions, so
+	 test whether the relevant bits were set and fail if not.  */
+      _FPU_GETCW (updated_fpscr);
+
+      if (new_fpscr & ~updated_fpscr)
+	return 1;
+    }
+
+  /* Raise the exceptions if enabled in the new FP state.  */
+  if (excepts & (new_fpscr >> FE_EXCEPT_SHIFT))
+    return feraiseexcept (excepts);
+
+  return 0;
+}