1 files changed, 73 insertions, 0 deletions
diff --git a/libm/aarch64/fesetenv.c b/libm/aarch64/fesetenv.c
new file mode 100644
index 000000000..eb7a08da0
--- /dev/null
+++ b/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;
+}