1 files changed, 55 insertions, 0 deletions
diff --git a/sysdeps/i386/setfpucw.c b/sysdeps/i386/setfpucw.c
new file mode 100644
index 0000000000..0a6af25ddf
--- /dev/null
+++ b/sysdeps/i386/setfpucw.c
@@ -0,0 +1,55 @@
+/* Set the FPU control word for x86.
+   Copyright (C) 2003 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <math.h>
+#include <fpu_control.h>
+#include <fenv.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <dl-procinfo.h>
+
+void
+__setfpucw (fpu_control_t set)
+{
+  fpu_control_t cw;
+
+  /* Fetch the current control word.  */
+  __asm__ ("fnstcw %0" : "=m" (*&cw));
+
+  /* Preserve the reserved bits, and set the rest as the user
+     specified (or the default, if the user gave zero).  */
+  cw &= _FPU_RESERVED;
+  cw |= set & ~_FPU_RESERVED;
+
+  __asm__ ("fldcw %0" : : "m" (*&cw));
+
+  /* If the CPU supports SSE, we set the MXCSR as well.  */
+  if ((GL(dl_hwcap) & HWCAP_I386_XMM) != 0)
+    {
+      unsigned int xnew_exc;
+
+      /* Get the current MXCSR.  */
+      __asm__ ("stmxcsr %0" : "=m" (*&xnew_exc));
+
+      xnew_exc &= ~((0xc00 << 3) | (FE_ALL_EXCEPT << 7));
+      xnew_exc |= ((set & 0xc00) << 3) | ((set & FE_ALL_EXCEPT) << 7);
+
+      __asm__ ("ldmxcsr %0" : : "m" (*&xnew_exc));
+    }
+}