csky: add fenv support from glibcHEADmaster

1 files changed, 55 insertions, 0 deletions

diff --git a/libm/csky/fesetenv.c b/libm/csky/fesetenv.c
new file mode 100644
index 000000000..96b961598
--- /dev/null
+++ b/libm/csky/fesetenv.c
@@ -0,0 +1,55 @@
+/* Install given floating-point environment.
+   Copyright (C) 2018-2025 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;
+
+  _FPU_GETCW (fpcr);
+  _FPU_GETFPSR (fpsr);
+
+  fpcr &= _FPU_RESERVED;
+  fpsr &= _FPU_FPSR_RESERVED;
+
+  if (envp == FE_DFL_ENV)
+    {
+      fpcr |= _FPU_DEFAULT;
+      fpsr |= _FPU_FPSR_DEFAULT;
+    }
+  else if (envp == FE_NOMASK_ENV)
+    {
+      fpcr |= _FPU_FPCR_IEEE;
+      fpsr |= _FPU_FPSR_IEEE;
+    }
+  else
+    {
+      fpcr |= envp->__fpcr & ~_FPU_RESERVED;
+      fpsr |= envp->__fpsr & ~_FPU_FPSR_RESERVED;
+    }
+
+  _FPU_SETFPSR (fpsr);
+
+  _FPU_SETCW (fpcr);
+
+  /* Success.  */
+  return 0;
+}