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[01/12] Add femode_t functions


TS 18661-1 defines a type femode_t to represent the set of dynamic
floating-point control modes (such as the rounding mode and trap
enablement modes), and functions fegetmode and fesetmode to manipulate
those modes (without affecting other state such as the raised
exception flags) and a corresponding macro FE_DFL_MODE.

This patch series implements those interfaces for glibc.  This first
patch adds the architecture-independent pieces, the x86 and x86_64
implementations, and the <bits/fenv.h> and ABI baseline updates for
all architectures so glibc keeps building and passing the ABI tests on
all architectures.  Subsequent patches add the fegetmode and fesetmode
implementations for other architectures.

femode_t is generally an integer type - the same type as fenv_t, or as
the single element of fenv_t where fenv_t is a structure containing a
single integer (or the single relevant element, where it has elements
for both status and control registers) - except where architecture
properties or consistency with the fenv_t implementation indicate
otherwise.  FE_DFL_MODE follows FE_DFL_ENV in whether it's a magic
pointer value (-1 cast to const femode_t *), a value that can be
distinguished from valid pointers by its high bits but otherwise
contains a representation of the desired register contents, or a
pointer to a constant variable (the powerpc case; __fe_dfl_mode is
added as an exported constant object, an alias to __fe_dfl_env).

Note that where architectures (that share a register between control
and status bits) gain definitions of new floating-point control or
status bits in future, the implementations of fesetmode for those
architectures may need updating (depending on whether the new bits are
control or status bits and what the implementation does with
previously unknown bits), just like existing implementations of
<fenv.h> functions that take care not to touch reserved bits may need
updating when the set of reserved bits changes.  (As any new bits are
outside the scope of ISO C, that's just a quality-of-implementation
issue for supporting them, not a conformance issue.)

As with fenv_t, femode_t should properly include any software DFP
rounding mode (and for both fenv_t and femode_t I'd consider that
fragment of DFP support appropriate for inclusion in glibc even in the
absence of the rest of libdfp; hardware DFP rounding modes should
already be included if the definitions of which bits are status /
control bits are correct).

Tested for x86_64, x86, mips64 (hard float, and soft float to test the
fallback version), arm (hard float) and powerpc (hard float, soft
float and e500).  Other architecture versions are untested.

I intend to commit this patch series on Wednesday.

2016-09-02  Joseph Myers  <joseph@codesourcery.com>

	* math/fegetmode.c: New file.
	* math/fesetmode.c: Likewise.
	* sysdeps/i386/fpu/fegetmode.c: Likewise.
	* sysdeps/i386/fpu/fesetmode.c: Likewise.
	* sysdeps/x86_64/fpu/fegetmode.c: Likewise.
	* sysdeps/x86_64/fpu/fesetmode.c: Likewise.
	* math/fenv.h: Update comment on inclusion of <bits/fenv.h>.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (fegetmode): New function
	declaration.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (fesetmode): Likewise.
	* bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (femode_t): New
	typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/aarch64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/alpha/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/arm/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/hppa/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/ia64/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/m68k/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/microblaze/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/mips/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/nios2/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/powerpc/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (__fe_dfl_mode): New variable
	declaration.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/s390/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/sh/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/sparc/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/tile/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* sysdeps/x86/fpu/bits/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(femode_t): New typedef.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FE_DFL_MODE): New macro.
	* manual/arith.texi (FE_DFL_MODE): Document macro.
	(fegetmode): Document function.
	(fesetmode): Likewise.
	* math/Versions (fegetmode): New libm symbol at version
	GLIBC_2.25.
	(fesetmode): Likewise.
	* math/Makefile (libm-support): Add fegetmode and fesetmode.
	(tests): Add test-femode and test-femode-traps.
	* math/test-femode-traps.c: New file.
	* math/test-femode.c: Likewise.
	* sysdeps/powerpc/fpu/fenv_const.c (__fe_dfl_mode): Declare as
	alias for __fe_dfl_env.
	* sysdeps/powerpc/nofpu/fenv_const.c (__fe_dfl_mode): Likewise.
	* sysdeps/powerpc/powerpc32/e500/nofpu/fenv_const.c
	(__fe_dfl_mode): Likewise.
	* sysdeps/powerpc/Versions (__fe_dfl_mode): New libm symbol at
	version GLIBC_2.25.
	* sysdeps/nacl/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.

diff --git a/NEWS b/NEWS
index 369655f..ba1ec71 100644
--- a/NEWS
+++ b/NEWS
@@ -32,8 +32,9 @@ Version 2.25
   presently cannot avoid being compiled under _GNU_SOURCE, exacerbating the
   problem.
 
-* The fesetexcept and fetestexceptflag functions from TS 18661-1:2014 are
-  added to libm.
+* New <fenv.h> features from TS 18661-1:2014 are added to libm: the
+  fesetexcept, fetestexceptflag, fegetmode and fesetmode functions,
+  the femode_t type and the FE_DFL_MODE macro.
 
 * The <sys/quota.h> header now includes the <linux/quota.h> header.  Support
   for the Linux quota interface which predates kernel version 2.4.22 has
diff --git a/bits/fenv.h b/bits/fenv.h
index f9b61d5..deeceee 100644
--- a/bits/fenv.h
+++ b/bits/fenv.h
@@ -53,3 +53,11 @@ fenv_t;
 
 /* If the default argument is used we use this value.  */
 #define FE_DFL_ENV	((const fenv_t *) -1l)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/manual/arith.texi b/manual/arith.texi
index 3a04bc2..23b9373 100644
--- a/manual/arith.texi
+++ b/manual/arith.texi
@@ -1127,6 +1127,39 @@ non-zero value otherwise.
 @end deftypefun
 
 @noindent
+TS 18661-1:2014 defines additional functions to save and restore
+floating-point control modes (such as the rounding mode and whether
+traps are enabled) while leaving other status (such as raised flags)
+unchanged.
+
+@vindex FE_DFL_MODE
+The special macro @code{FE_DFL_MODE} may be passed to
+@code{fesetmode}.  It represents the floating-point control modes at
+program start.
+
+@comment fenv.h
+@comment ISO
+@deftypefun int fegetmode (femode_t *@var{modep})
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+Store the floating-point control modes in the variable pointed to by
+@var{modep}.
+
+The function returns zero in case the operation was successful, a
+non-zero value otherwise.
+@end deftypefun
+
+@comment fenv.h
+@comment ISO
+@deftypefun int fesetmode (const femode_t *@var{modep})
+@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
+Set the floating-point control modes to those described by
+@var{modep}.
+
+The function returns zero in case the operation was successful, a
+non-zero value otherwise.
+@end deftypefun
+
+@noindent
 To control for individual exceptions if raising them causes a trap to
 occur, you can use the following two functions.
 
diff --git a/math/Makefile b/math/Makefile
index 6a90a36..fc48960 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -41,7 +41,8 @@ libm-support = s_lib_version s_matherr s_signgam			\
 	       fclrexcpt fgetexcptflg fraiseexcpt fsetexcptflg		\
 	       ftestexcept fegetround fesetround fegetenv feholdexcpt	\
 	       fesetenv feupdateenv t_exp fedisblxcpt feenablxcpt	\
-	       fegetexcept fesetexcept fetestexceptflag
+	       fegetexcept fesetexcept fetestexceptflag fegetmode	\
+	       fesetmode
 
 # Wrappers for these functions generated per type using a file named
 # <func>_template.c and the appropriate math-type-macros-<TYPE>.h.
@@ -152,7 +153,8 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
 	test-signgam-uint test-signgam-uint-init test-signgam-ullong \
 	test-signgam-ullong-init test-nan-overflow test-nan-payload \
 	test-fexcept test-fexcept-traps test-fesetexcept \
-	test-fesetexcept-traps test-fetestexceptflag $(tests-static)
+	test-fesetexcept-traps test-fetestexceptflag test-femode \
+	test-femode-traps $(tests-static)
 tests-static = test-fpucw-static test-fpucw-ieee-static \
 	       test-signgam-uchar-static test-signgam-uchar-init-static \
 	       test-signgam-uint-static test-signgam-uint-init-static \
diff --git a/math/Versions b/math/Versions
index 1c1683f..a429221 100644
--- a/math/Versions
+++ b/math/Versions
@@ -215,6 +215,6 @@ libm {
     nextdown; nextdownf; nextdownl;
   }
   GLIBC_2.25 {
-    fesetexcept; fetestexceptflag;
+    fesetexcept; fetestexceptflag; fegetmode; fesetmode;
   }
 }
diff --git a/math/fegetmode.c b/math/fegetmode.c
new file mode 100644
index 0000000..25f299f
--- /dev/null
+++ b/math/fegetmode.c
@@ -0,0 +1,27 @@
+/* Store current floating-point control modes.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+
+int
+fegetmode (femode_t *modep)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+stub_warning (fegetmode)
diff --git a/math/fenv.h b/math/fenv.h
index 10d32db..9006aa2 100644
--- a/math/fenv.h
+++ b/math/fenv.h
@@ -38,6 +38,12 @@
    fexcept_t	type for object representing the floating-point exception
 		flags including status associated with the flags
 
+   femode_t	type for object representing floating-point control modes
+
+   FE_DFL_MODE	macro of type pointer to const femode_t to be used as the
+		argument to fesetmode; in this case the default control
+		modes will be used
+
    The following macros are defined iff the implementation supports this
    kind of exception.
    FE_INEXACT		inexact result
@@ -122,6 +128,18 @@ extern int fesetenv (const fenv_t *__envp) __THROW;
 extern int feupdateenv (const fenv_t *__envp) __THROW;
 
 
+/* Control modes.  */
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Store the current floating-point control modes in the object
+   pointed to by MODEP.  */
+extern int fegetmode (femode_t *__modep) __THROW;
+
+/* Establish the floating-point control modes represented by the
+   object pointed to by MODEP.  */
+extern int fesetmode (const femode_t *__modep) __THROW;
+#endif
+
 /* Include optimization.  */
 #ifdef __OPTIMIZE__
 # include <bits/fenvinline.h>
diff --git a/math/fesetmode.c b/math/fesetmode.c
new file mode 100644
index 0000000..0d040e4
--- /dev/null
+++ b/math/fesetmode.c
@@ -0,0 +1,27 @@
+/* Install given floating-point control modes.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+
+int
+fesetmode (const femode_t *modep)
+{
+  /* Nothing to do.  */
+  return 0;
+}
+stub_warning (fesetmode)
diff --git a/math/test-femode-traps.c b/math/test-femode-traps.c
new file mode 100644
index 0000000..dd22765
--- /dev/null
+++ b/math/test-femode-traps.c
@@ -0,0 +1,149 @@
+/* Test femode_t functions: test handling of exception traps.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <stdio.h>
+#include <math-tests.h>
+
+static int
+test_ee (int exc1, int exc2)
+{
+  int result = 0;
+  printf ("testing %x %x\n", (unsigned int) exc1, (unsigned int) exc2);
+
+  fedisableexcept (FE_ALL_EXCEPT);
+  int ret = feenableexcept (exc1);
+  if (ret == -1)
+    {
+      if (EXCEPTION_ENABLE_SUPPORTED (exc1))
+	{
+	  puts ("first feenableexcept failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("first feenableexcept failed, cannot test");
+      return result;
+    }
+  femode_t saved;
+  ret = fegetmode (&saved);
+  if (ret != 0)
+    {
+      puts ("fegetmode failed");
+      result = 1;
+      return result;
+    }
+  fedisableexcept (FE_ALL_EXCEPT);
+  ret = feenableexcept (exc2);
+  if (ret == -1)
+    {
+      if (EXCEPTION_ENABLE_SUPPORTED (exc2))
+	{
+	  puts ("second feenableexcept failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("second feenableexcept failed, cannot test");
+      return result;
+    }
+  ret = fesetmode (&saved);
+  if (ret != 0)
+    {
+      puts ("fesetmode failed");
+      result = 1;
+      return result;
+    }
+  /* Verify that the set of enabled traps was restored.  */
+  ret = fegetexcept ();
+  if (ret != exc1)
+    {
+      printf ("restored enabled traps %x not %x\n", (unsigned int) ret,
+	      (unsigned int) exc1);
+      result = 1;
+    }
+  /* Likewise, with default modes.  */
+  ret = fesetmode (FE_DFL_MODE);
+  if (ret != 0)
+    {
+      puts ("fesetmode (FE_DFL_MODE) failed");
+      result = 1;
+      return result;
+    }
+  ret = fegetexcept ();
+  if (ret != 0)
+    {
+      printf ("FE_DFL_MODE enabled traps %x not 0\n", (unsigned int) ret);
+      result = 1;
+    }
+
+  return result;
+}
+
+static int
+test_e (int exc1)
+{
+  int result = 0;
+
+  result |= test_ee (exc1, 0);
+  result |= test_ee (exc1, FE_ALL_EXCEPT);
+#ifdef FE_DIVBYZERO
+  result |= test_ee (exc1, FE_DIVBYZERO);
+#endif
+#ifdef FE_INEXACT
+  result |= test_ee (exc1, FE_INEXACT);
+#endif
+#ifdef FE_INVALID
+  result |= test_ee (exc1, FE_INVALID);
+#endif
+#ifdef FE_OVERFLOW
+  result |= test_ee (exc1, FE_OVERFLOW);
+#endif
+#ifdef FE_UNDERFLOW
+  result |= test_ee (exc1, FE_UNDERFLOW);
+#endif
+
+  return result;
+}
+
+static int
+do_test (void)
+{
+  int result = 0;
+
+  result |= test_e (0);
+  result |= test_e (FE_ALL_EXCEPT);
+#ifdef FE_DIVBYZERO
+  result |= test_e (FE_DIVBYZERO);
+#endif
+#ifdef FE_INEXACT
+  result |= test_e (FE_INEXACT);
+#endif
+#ifdef FE_INVALID
+  result |= test_e (FE_INVALID);
+#endif
+#ifdef FE_OVERFLOW
+  result |= test_e (FE_OVERFLOW);
+#endif
+#ifdef FE_UNDERFLOW
+  result |= test_e (FE_UNDERFLOW);
+#endif
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/math/test-femode.c b/math/test-femode.c
new file mode 100644
index 0000000..1e80f32
--- /dev/null
+++ b/math/test-femode.c
@@ -0,0 +1,231 @@
+/* Test femode_t functions.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <stdio.h>
+#include <math-tests.h>
+
+static int
+test_mmee (int mode1, int mode2, int exc1, int exc2)
+{
+  int result = 0;
+  printf ("testing %x %x %x %x\n", (unsigned int) mode1, (unsigned int) mode2,
+	  (unsigned int) exc1, (unsigned int) exc2);
+
+  feclearexcept (FE_ALL_EXCEPT);
+  int ret = fesetround (mode1);
+  if (ret != 0)
+    {
+      if (ROUNDING_TESTS (float, mode1))
+	{
+	  puts ("first fesetround failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("first fesetround failed, cannot test");
+      return result;
+    }
+  ret = fesetexcept (exc1);
+  if (ret != 0)
+    {
+      if (EXCEPTION_TESTS (float) || exc1 == 0)
+	{
+	  puts ("first fesetexcept failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("first fesetexcept failed, cannot test");
+      return result;
+    }
+  femode_t saved;
+  ret = fegetmode (&saved);
+  if (ret != 0)
+    {
+      puts ("fegetmode failed");
+      result = 1;
+      return result;
+    }
+  feclearexcept (FE_ALL_EXCEPT);
+  ret = fesetround (mode2);
+  if (ret != 0)
+    {
+      if (ROUNDING_TESTS (float, mode2))
+	{
+	  puts ("second fesetround failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("second fesetround failed, cannot test");
+      return result;
+    }
+  ret = fesetexcept (exc2);
+  if (ret != 0)
+    {
+      if (EXCEPTION_TESTS (float) || exc2 == 0)
+	{
+	  puts ("second fesetexcept failed unexpectedly");
+	  result = 1;
+	}
+      else
+	puts ("second fesetexcept failed, cannot test");
+      return result;
+    }
+  ret = fesetmode (&saved);
+  if (ret != 0)
+    {
+      puts ("fesetmode failed");
+      result = 1;
+      return result;
+    }
+  /* Verify that the rounding mode was restored but the exception
+     flags remain unchanged.  */
+  ret = fegetround ();
+  if (ret != mode1)
+    {
+      printf ("restored rounding mode %x not %x\n", (unsigned int) ret,
+	      (unsigned int) mode1);
+      result = 1;
+    }
+  ret = fetestexcept (FE_ALL_EXCEPT);
+  if (ret != exc2)
+    {
+      printf ("exceptions %x not %x\n", (unsigned int) ret,
+	      (unsigned int) exc2);
+      result = 1;
+    }
+  /* Likewise, with default modes.  */
+  ret = fesetmode (FE_DFL_MODE);
+  if (ret != 0)
+    {
+      puts ("fesetmode (FE_DFL_MODE) failed");
+      result = 1;
+      return result;
+    }
+  ret = fegetround ();
+  if (ret != FE_TONEAREST)
+    {
+      printf ("FE_DFL_MODE rounding mode %x not %x\n", (unsigned int) ret,
+	      (unsigned int) FE_TONEAREST);
+      result = 1;
+    }
+  ret = fetestexcept (FE_ALL_EXCEPT);
+  if (ret != exc2)
+    {
+      printf ("FE_DFL_MODE exceptions %x not %x\n", (unsigned int) ret,
+	      (unsigned int) exc2);
+      result = 1;
+    }
+  return result;
+}
+
+static int
+test_mme (int mode1, int mode2, int exc1)
+{
+  int result = 0;
+
+  result |= test_mmee (mode1, mode2, exc1, 0);
+  result |= test_mmee (mode1, mode2, exc1, FE_ALL_EXCEPT);
+#ifdef FE_DIVBYZERO
+  result |= test_mmee (mode1, mode2, exc1, FE_DIVBYZERO);
+#endif
+#ifdef FE_INEXACT
+  result |= test_mmee (mode1, mode2, exc1, FE_INEXACT);
+#endif
+#ifdef FE_INVALID
+  result |= test_mmee (mode1, mode2, exc1, FE_INVALID);
+#endif
+#ifdef FE_OVERFLOW
+  result |= test_mmee (mode1, mode2, exc1, FE_OVERFLOW);
+#endif
+#ifdef FE_UNDERFLOW
+  result |= test_mmee (mode1, mode2, exc1, FE_UNDERFLOW);
+#endif
+
+  return result;
+}
+
+static int
+test_mm (int mode1, int mode2)
+{
+  int result = 0;
+
+  result |= test_mme (mode1, mode2, 0);
+  result |= test_mme (mode1, mode2, FE_ALL_EXCEPT);
+#ifdef FE_DIVBYZERO
+  result |= test_mme (mode1, mode2, FE_DIVBYZERO);
+#endif
+#ifdef FE_INEXACT
+  result |= test_mme (mode1, mode2, FE_INEXACT);
+#endif
+#ifdef FE_INVALID
+  result |= test_mme (mode1, mode2, FE_INVALID);
+#endif
+#ifdef FE_OVERFLOW
+  result |= test_mme (mode1, mode2, FE_OVERFLOW);
+#endif
+#ifdef FE_UNDERFLOW
+  result |= test_mme (mode1, mode2, FE_UNDERFLOW);
+#endif
+
+  return result;
+}
+
+static int
+test_m (int mode1)
+{
+  int result = 0;
+
+#ifdef FE_DOWNWARD
+  result |= test_mm (mode1, FE_DOWNWARD);
+#endif
+#ifdef FE_TONEAREST
+  result |= test_mm (mode1, FE_TONEAREST);
+#endif
+#ifdef FE_TOWARDZERO
+  result |= test_mm (mode1, FE_TOWARDZERO);
+#endif
+#ifdef FE_UPWARD
+  result |= test_mm (mode1, FE_UPWARD);
+#endif
+
+  return result;
+}
+
+static int
+do_test (void)
+{
+  int result = 0;
+
+#ifdef FE_DOWNWARD
+  result |= test_m (FE_DOWNWARD);
+#endif
+#ifdef FE_TONEAREST
+  result |= test_m (FE_TONEAREST);
+#endif
+#ifdef FE_TOWARDZERO
+  result |= test_m (FE_TOWARDZERO);
+#endif
+#ifdef FE_UPWARD
+  result |= test_m (FE_UPWARD);
+#endif
+
+  return result;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/aarch64/bits/fenv.h b/sysdeps/aarch64/bits/fenv.h
index aced0d3..9df57a1 100644
--- a/sysdeps/aarch64/bits/fenv.h
+++ b/sysdeps/aarch64/bits/fenv.h
@@ -72,3 +72,11 @@ fenv_t;
 /* Floating-point environment where none of the exceptions are masked.  */
 # define FE_NOMASK_ENV  ((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/alpha/fpu/bits/fenv.h b/sysdeps/alpha/fpu/bits/fenv.h
index b7da4a0..0688898 100644
--- a/sysdeps/alpha/fpu/bits/fenv.h
+++ b/sysdeps/alpha/fpu/bits/fenv.h
@@ -131,3 +131,11 @@ typedef unsigned long int fenv_t;
 /* The system calls to talk to the kernel's FP code.  */
 extern unsigned long int __ieee_get_fp_control (void) __THROW;
 extern void __ieee_set_fp_control (unsigned long int __value) __THROW;
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned long int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) 0x8800000000000000UL)
+#endif
diff --git a/sysdeps/arm/bits/fenv.h b/sysdeps/arm/bits/fenv.h
index 8e89fc1..c82fecb 100644
--- a/sysdeps/arm/bits/fenv.h
+++ b/sysdeps/arm/bits/fenv.h
@@ -80,3 +80,11 @@ fenv_t;
 /* Floating-point environment where none of the exceptions are masked.  */
 # define FE_NOMASK_ENV  ((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/hppa/fpu/bits/fenv.h b/sysdeps/hppa/fpu/bits/fenv.h
index cae9dae..e35e355 100644
--- a/sysdeps/hppa/fpu/bits/fenv.h
+++ b/sysdeps/hppa/fpu/bits/fenv.h
@@ -89,3 +89,11 @@ typedef struct
 /* Floating-point environment where none of the exceptions are masked.  */
 # define FE_NOMASK_ENV	((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/i386/fpu/fegetmode.c b/sysdeps/i386/fpu/fegetmode.c
new file mode 100644
index 0000000..06d4d84
--- /dev/null
+++ b/sysdeps/i386/fpu/fegetmode.c
@@ -0,0 +1,32 @@
+/* Store current floating-point control modes.  i386 version.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <fpu_control.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <dl-procinfo.h>
+
+int
+fegetmode (femode_t *modep)
+{
+  _FPU_GETCW (modep->__control_word);
+  if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
+    __asm__ ("stmxcsr %0" : "=m" (modep->__mxcsr));
+  return 0;
+}
diff --git a/sysdeps/i386/fpu/fesetmode.c b/sysdeps/i386/fpu/fesetmode.c
new file mode 100644
index 0000000..cca5a1a
--- /dev/null
+++ b/sysdeps/i386/fpu/fesetmode.c
@@ -0,0 +1,54 @@
+/* Install given floating-point control modes.  i386 version.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <fpu_control.h>
+#include <unistd.h>
+#include <ldsodefs.h>
+#include <dl-procinfo.h>
+
+/* All exceptions, including the x86-specific "denormal operand"
+   exception.  */
+#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
+
+int
+fesetmode (const femode_t *modep)
+{
+  fpu_control_t cw;
+  if (modep == FE_DFL_MODE)
+    cw = _FPU_DEFAULT;
+  else
+    cw = modep->__control_word;
+  _FPU_SETCW (cw);
+  if ((GLRO(dl_hwcap) & HWCAP_I386_XMM) != 0)
+    {
+      unsigned int mxcsr;
+      __asm__ ("stmxcsr %0" : "=m" (mxcsr));
+      /* Preserve SSE exception flags but restore other state in
+	 MXCSR.  */
+      mxcsr &= FE_ALL_EXCEPT_X86;
+      if (modep == FE_DFL_MODE)
+	/* Default MXCSR state has all bits zero except for those
+	   masking exceptions.  */
+	mxcsr |= FE_ALL_EXCEPT_X86 << 7;
+      else
+	mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86;
+      __asm__ ("ldmxcsr %0" : : "m" (mxcsr));
+    }
+  return 0;
+}
diff --git a/sysdeps/ia64/bits/fenv.h b/sysdeps/ia64/bits/fenv.h
index 9bb20de..5945380 100644
--- a/sysdeps/ia64/bits/fenv.h
+++ b/sysdeps/ia64/bits/fenv.h
@@ -94,3 +94,11 @@ typedef unsigned long int fenv_t;
    s0, s2, and s3.  */
 # define FE_NONIEEE_ENV ((const fenv_t *) 0xc009a04d0270037fUL)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned long int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) 0xc009804c0270033fUL)
+#endif
diff --git a/sysdeps/m68k/fpu/bits/fenv.h b/sysdeps/m68k/fpu/bits/fenv.h
index 2228861..b8e52b2 100644
--- a/sysdeps/m68k/fpu/bits/fenv.h
+++ b/sysdeps/m68k/fpu/bits/fenv.h
@@ -85,3 +85,11 @@ fenv_t;
 /* Floating-point environment where none of the exceptions are masked.  */
 # define FE_NOMASK_ENV	((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/microblaze/bits/fenv.h b/sysdeps/microblaze/bits/fenv.h
index 3891f4a..0d2ab2b 100644
--- a/sysdeps/microblaze/bits/fenv.h
+++ b/sysdeps/microblaze/bits/fenv.h
@@ -40,3 +40,11 @@ typedef unsigned int fenv_t;
 
 /* If the default argument is used we use this value.  */
 #define FE_DFL_ENV	((const fenv_t *) -1l)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/mips/bits/fenv.h b/sysdeps/mips/bits/fenv.h
index f829bd3..6341ee2 100644
--- a/sysdeps/mips/bits/fenv.h
+++ b/sysdeps/mips/bits/fenv.h
@@ -83,3 +83,11 @@ fenv_t;
 /* Floating-point environment where none of the exception is masked.  */
 # define FE_NOMASK_ENV  ((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/nacl/libm.abilist b/sysdeps/nacl/libm.abilist
index 2889773..85ee684 100644
--- a/sysdeps/nacl/libm.abilist
+++ b/sysdeps/nacl/libm.abilist
@@ -380,5 +380,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/nios2/bits/fenv.h b/sysdeps/nios2/bits/fenv.h
index 9d04621..8ac3831 100644
--- a/sysdeps/nios2/bits/fenv.h
+++ b/sysdeps/nios2/bits/fenv.h
@@ -42,3 +42,11 @@ typedef unsigned int fenv_t;
 
 /* If the default argument is used we use this value.  */
 #define FE_DFL_ENV	((const fenv_t *) -1)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/powerpc/Versions b/sysdeps/powerpc/Versions
index b959ea4..9584966 100644
--- a/sysdeps/powerpc/Versions
+++ b/sysdeps/powerpc/Versions
@@ -3,6 +3,9 @@ libm {
     # symbols used in macros from sysdeps/powerpc/bits/fenv.h
     __fe_dfl_env; __fe_enabled_env; __fe_nonieee_env; __fe_nomask_env;
   }
+  GLIBC_2.25 {
+    __fe_dfl_mode;
+  }
 }
 
 libc {
diff --git a/sysdeps/powerpc/bits/fenv.h b/sysdeps/powerpc/bits/fenv.h
index d2a6d34..8d2bf3d 100644
--- a/sysdeps/powerpc/bits/fenv.h
+++ b/sysdeps/powerpc/bits/fenv.h
@@ -169,3 +169,12 @@ extern const fenv_t __fe_nonieee_env;
 # define FE_MASK_ENV	FE_DFL_ENV
 
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef double femode_t;
+
+/* Default floating-point control modes.  */
+extern const femode_t __fe_dfl_mode;
+# define FE_DFL_MODE	(&__fe_dfl_mode)
+#endif
diff --git a/sysdeps/powerpc/fpu/fenv_const.c b/sysdeps/powerpc/fpu/fenv_const.c
index b061daf..93a4375 100644
--- a/sysdeps/powerpc/fpu/fenv_const.c
+++ b/sysdeps/powerpc/fpu/fenv_const.c
@@ -23,6 +23,10 @@
 const unsigned long long __fe_dfl_env __attribute__ ((aligned (8))) =
 0xfff8000000000000ULL;
 
+/* The same representation is used for femode_t.  */
+extern const unsigned long long __fe_dfl_mode
+  __attribute__ ((aligned (8), alias ("__fe_dfl_env")));
+
 /* Floating-point environment where none of the exceptions are masked.  */
 const unsigned long long __fe_enabled_env __attribute__ ((aligned (8))) =
 0xfff80000000000f8ULL;
diff --git a/sysdeps/powerpc/nofpu/fenv_const.c b/sysdeps/powerpc/nofpu/fenv_const.c
index ebf5c68..ce1da3c 100644
--- a/sysdeps/powerpc/nofpu/fenv_const.c
+++ b/sysdeps/powerpc/nofpu/fenv_const.c
@@ -25,6 +25,10 @@
 const unsigned long long __fe_dfl_env __attribute__ ((aligned (8))) =
 0x000000003e000000ULL;
 
+/* The same representation is used for femode_t.  */
+extern const unsigned long long __fe_dfl_mode
+  __attribute__ ((aligned (8), alias ("__fe_dfl_env")));
+
 /* Floating-point environment where none of the exceptions are masked.  */
 const unsigned long long __fe_enabled_env __attribute__ ((aligned (8))) =
 0x0000000000000000ULL;
diff --git a/sysdeps/powerpc/powerpc32/e500/nofpu/fenv_const.c b/sysdeps/powerpc/powerpc32/e500/nofpu/fenv_const.c
index 11e24ca..eab47c8 100644
--- a/sysdeps/powerpc/powerpc32/e500/nofpu/fenv_const.c
+++ b/sysdeps/powerpc/powerpc32/e500/nofpu/fenv_const.c
@@ -28,6 +28,10 @@
 const unsigned long long __fe_dfl_env __attribute__ ((aligned (8))) =
   0x3cULL;
 
+/* The same representation is used for femode_t.  */
+extern const unsigned long long __fe_dfl_mode
+  __attribute__ ((aligned (8), alias ("__fe_dfl_env")));
+
 /* Floating-point environment where none of the exceptions are masked.  */
 const unsigned long long __fe_enabled_env __attribute__ ((aligned (8))) =
   (((unsigned long long) (PR_FP_EXC_DIV
diff --git a/sysdeps/s390/fpu/bits/fenv.h b/sysdeps/s390/fpu/bits/fenv.h
index 6de74b9..d33f5d9 100644
--- a/sysdeps/s390/fpu/bits/fenv.h
+++ b/sysdeps/s390/fpu/bits/fenv.h
@@ -90,3 +90,11 @@ typedef struct
 /* Floating-point environment where none of the exceptions are masked.  */
 # define FE_NOMASK_ENV	((const fenv_t *) -2)
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/sh/bits/fenv.h b/sysdeps/sh/bits/fenv.h
index 254c50f..200b538 100644
--- a/sysdeps/sh/bits/fenv.h
+++ b/sysdeps/sh/bits/fenv.h
@@ -74,3 +74,11 @@ fenv_t;
 
 /* If the default argument is used we use this value.  */
 #define FE_DFL_ENV	((const fenv_t *) -1)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/sparc/fpu/bits/fenv.h b/sysdeps/sparc/fpu/bits/fenv.h
index 29328f7..37c82ff 100644
--- a/sysdeps/sparc/fpu/bits/fenv.h
+++ b/sysdeps/sparc/fpu/bits/fenv.h
@@ -91,3 +91,11 @@ typedef unsigned long int fenv_t;
 # define __fenv_stfsr(X)   __asm__ __volatile__ ("st %%fsr,%0" : "=m" (X))
 # define __fenv_ldfsr(X)   __asm__ __volatile__ ("ld %0,%%fsr" : : "m" (X))
 #endif
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned long int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/tile/bits/fenv.h b/sysdeps/tile/bits/fenv.h
index a87a39f..eee9e01 100644
--- a/sysdeps/tile/bits/fenv.h
+++ b/sysdeps/tile/bits/fenv.h
@@ -43,3 +43,11 @@ typedef unsigned int fenv_t;
 
 /* If the default argument is used we use this value.  */
 #define FE_DFL_ENV	((const fenv_t *) -1l)
+
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef unsigned int femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
diff --git a/sysdeps/unix/sysv/linux/aarch64/libm.abilist b/sysdeps/unix/sysv/linux/aarch64/libm.abilist
index 1f475cd..aee63a1 100644
--- a/sysdeps/unix/sysv/linux/aarch64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/aarch64/libm.abilist
@@ -411,5 +411,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/alpha/libm.abilist b/sysdeps/unix/sysv/linux/alpha/libm.abilist
index 11b76e9..339b896 100644
--- a/sysdeps/unix/sysv/linux/alpha/libm.abilist
+++ b/sysdeps/unix/sysv/linux/alpha/libm.abilist
@@ -421,7 +421,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.3.4 GLIBC_2.3.4 A
 GLIBC_2.3.4 __c1_cabsf F
diff --git a/sysdeps/unix/sysv/linux/arm/libm.abilist b/sysdeps/unix/sysv/linux/arm/libm.abilist
index 1fc1804..f7b8244 100644
--- a/sysdeps/unix/sysv/linux/arm/libm.abilist
+++ b/sysdeps/unix/sysv/linux/arm/libm.abilist
@@ -69,7 +69,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 _LIB_VERSION D 0x4
diff --git a/sysdeps/unix/sysv/linux/hppa/libm.abilist b/sysdeps/unix/sysv/linux/hppa/libm.abilist
index ed73488..576b514 100644
--- a/sysdeps/unix/sysv/linux/hppa/libm.abilist
+++ b/sysdeps/unix/sysv/linux/hppa/libm.abilist
@@ -381,7 +381,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 exp2l F
diff --git a/sysdeps/unix/sysv/linux/i386/libm.abilist b/sysdeps/unix/sysv/linux/i386/libm.abilist
index 3a6dcaf..63b8da9 100644
--- a/sysdeps/unix/sysv/linux/i386/libm.abilist
+++ b/sysdeps/unix/sysv/linux/i386/libm.abilist
@@ -423,6 +423,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/ia64/libm.abilist b/sysdeps/unix/sysv/linux/ia64/libm.abilist
index ec9916b..611a84f 100644
--- a/sysdeps/unix/sysv/linux/ia64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/ia64/libm.abilist
@@ -352,6 +352,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist b/sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist
index 1fc1804..f7b8244 100644
--- a/sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist
@@ -69,7 +69,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 _LIB_VERSION D 0x4
diff --git a/sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist b/sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist
index 32931f1..77f9c7b 100644
--- a/sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist
+++ b/sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist
@@ -421,6 +421,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/microblaze/libm.abilist b/sysdeps/unix/sysv/linux/microblaze/libm.abilist
index cab693a..c59437f 100644
--- a/sysdeps/unix/sysv/linux/microblaze/libm.abilist
+++ b/sysdeps/unix/sysv/linux/microblaze/libm.abilist
@@ -380,5 +380,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/mips/mips32/libm.abilist b/sysdeps/unix/sysv/linux/mips/mips32/libm.abilist
index 20a80cc..31d6f9e 100644
--- a/sysdeps/unix/sysv/linux/mips/mips32/libm.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips32/libm.abilist
@@ -382,7 +382,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 exp2l F
diff --git a/sysdeps/unix/sysv/linux/mips/mips64/libm.abilist b/sysdeps/unix/sysv/linux/mips/mips64/libm.abilist
index 02379f7..83e0311 100644
--- a/sysdeps/unix/sysv/linux/mips/mips64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/mips/mips64/libm.abilist
@@ -413,6 +413,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/nios2/libm.abilist b/sysdeps/unix/sysv/linux/nios2/libm.abilist
index b4b377b..151574d 100644
--- a/sysdeps/unix/sysv/linux/nios2/libm.abilist
+++ b/sysdeps/unix/sysv/linux/nios2/libm.abilist
@@ -380,5 +380,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist
index 7eea14a..456f47e 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist
@@ -422,7 +422,10 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 __fe_dfl_mode D 0x8
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 __clog10l F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist
index 5eb2e9b..b2e4a73 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist
@@ -421,7 +421,10 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 __fe_dfl_mode D 0x8
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 __clog10l F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist
index 36b8e77..907d8b7 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist
@@ -416,5 +416,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 __fe_dfl_mode D 0x8
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist
index 2efd4eb..307423d 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist
@@ -97,7 +97,10 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 __fe_dfl_mode D 0x8
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.3 GLIBC_2.3 A
 GLIBC_2.3 _LIB_VERSION D 0x4
diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist b/sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist
index 62f75ba..377cea9 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-32/libm.abilist
@@ -411,7 +411,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 __clog10l F
diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist b/sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist
index c41344a..dafbff1 100644
--- a/sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist
@@ -409,7 +409,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 __clog10l F
diff --git a/sysdeps/unix/sysv/linux/sh/libm.abilist b/sysdeps/unix/sysv/linux/sh/libm.abilist
index 3baecfb..a38bace 100644
--- a/sysdeps/unix/sysv/linux/sh/libm.abilist
+++ b/sysdeps/unix/sysv/linux/sh/libm.abilist
@@ -381,7 +381,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 exp2l F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist b/sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist
index dd5390c..27166be 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist
@@ -414,7 +414,9 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
 GLIBC_2.4 __clog10l F
diff --git a/sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist b/sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist
index 394c29b..46f7973 100644
--- a/sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist
@@ -412,6 +412,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist
index d66c886..ec6f0b3 100644
--- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist
@@ -381,5 +381,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist
index d66c886..ec6f0b3 100644
--- a/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist
@@ -381,5 +381,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist b/sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist
index d66c886..ec6f0b3 100644
--- a/sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist
+++ b/sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist
@@ -381,5 +381,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/unix/sysv/linux/x86_64/64/libm.abilist b/sysdeps/unix/sysv/linux/x86_64/64/libm.abilist
index dd79dc4..65e5bae 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/libm.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/64/libm.abilist
@@ -412,6 +412,8 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
 GLIBC_2.4 GLIBC_2.4 A
diff --git a/sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist b/sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist
index 45abb4f..ff520cb 100644
--- a/sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist
+++ b/sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist
@@ -411,5 +411,7 @@ GLIBC_2.24 nextup F
 GLIBC_2.24 nextupf F
 GLIBC_2.24 nextupl F
 GLIBC_2.25 GLIBC_2.25 A
+GLIBC_2.25 fegetmode F
 GLIBC_2.25 fesetexcept F
+GLIBC_2.25 fesetmode F
 GLIBC_2.25 fetestexceptflag F
diff --git a/sysdeps/x86/fpu/bits/fenv.h b/sysdeps/x86/fpu/bits/fenv.h
index 8c8503b..6884072 100644
--- a/sysdeps/x86/fpu/bits/fenv.h
+++ b/sysdeps/x86/fpu/bits/fenv.h
@@ -101,6 +101,20 @@ fenv_t;
 # define FE_NOMASK_ENV	((const fenv_t *) -2)
 #endif
 
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Type representing floating-point control modes.  */
+typedef struct
+  {
+    unsigned short int __control_word;
+    unsigned short int __glibc_reserved;
+    unsigned int __mxcsr;
+  }
+femode_t;
+
+/* Default floating-point control modes.  */
+# define FE_DFL_MODE	((const femode_t *) -1L)
+#endif
+
 
 #ifdef __USE_EXTERN_INLINES
 __BEGIN_DECLS
diff --git a/sysdeps/x86_64/fpu/fegetmode.c b/sysdeps/x86_64/fpu/fegetmode.c
new file mode 100644
index 0000000..f4a179d
--- /dev/null
+++ b/sysdeps/x86_64/fpu/fegetmode.c
@@ -0,0 +1,28 @@
+/* Store current floating-point control modes.  x86_64 version.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <fpu_control.h>
+
+int
+fegetmode (femode_t *modep)
+{
+  _FPU_GETCW (modep->__control_word);
+  __asm__ ("stmxcsr %0" : "=m" (modep->__mxcsr));
+  return 0;
+}
diff --git a/sysdeps/x86_64/fpu/fesetmode.c b/sysdeps/x86_64/fpu/fesetmode.c
new file mode 100644
index 0000000..19173f9
--- /dev/null
+++ b/sysdeps/x86_64/fpu/fesetmode.c
@@ -0,0 +1,50 @@
+/* Install given floating-point control modes.  x86_64 version.
+   Copyright (C) 2016 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, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <fenv.h>
+#include <fpu_control.h>
+
+/* All exceptions, including the x86-specific "denormal operand"
+   exception.  */
+#define FE_ALL_EXCEPT_X86 (FE_ALL_EXCEPT | __FE_DENORM)
+
+int
+fesetmode (const femode_t *modep)
+{
+  fpu_control_t cw;
+  unsigned int mxcsr;
+  __asm__ ("stmxcsr %0" : "=m" (mxcsr));
+  /* Preserve SSE exception flags but restore other state in
+     MXCSR.  */
+  mxcsr &= FE_ALL_EXCEPT_X86;
+  if (modep == FE_DFL_MODE)
+    {
+      cw = _FPU_DEFAULT;
+      /* Default MXCSR state has all bits zero except for those
+	 masking exceptions.  */
+      mxcsr |= FE_ALL_EXCEPT_X86 << 7;
+    }
+  else
+    {
+      cw = modep->__control_word;
+      mxcsr |= modep->__mxcsr & ~FE_ALL_EXCEPT_X86;
+    }
+  _FPU_SETCW (cw);
+  __asm__ ("ldmxcsr %0" : : "m" (mxcsr));
+  return 0;
+}

-- 
Joseph S. Myers
joseph@codesourcery.com


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