Add fetestexceptflag.

TS 18661-1 defines an fetestexceptflag function to test the exception
state saved in an fexcept_t object by fegetexceptflag.

This patch implements this function for glibc.  Almost all
architectures save exception state in such a way that it can be
directly ANDed with exception flag bits, so rather than having lots of
fetestexceptflag implementations that all do the same thing, the math/
implementation is made to use this generic logic (which is also OK in
the fallback case where FE_ALL_EXCEPT is zero).  The only architecture
that seems to need anything different is s390.

(fegetexceptflag and fesetexceptflag use abbreviated filenames
fgetexcptflg.c and fsetexcptflg.c.  Because we are no longer concerned
by 14-character filename limits, fetestexceptflag uses the obvious
filename fetestexceptflag.c.)

The NEWS entry is intended to be expanded along the lines given in
<https://sourceware.org/ml/libc-alpha/2016-08/msg00356.html> when
fegetmode and fesetmode are added.

Tested for x86_64, x86, mips64 and powerpc.

	* math/fetestexceptflag.c: New file.
	* sysdeps/s390/fpu/fetestexceptflag.c: Likewise.  Comment by
	Stefan Liebler.
	* math/fenv.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(fetestexceptflag): New function declaration.
	* manual/arith.texi (fetestexceptflag): Document function.
	* math/Versions (fetestexceptflag): New libm symbol at version
	GLIBC_2.25.
	* math/Makefile (libm-support): Add fetestexceptflag.
	(tests): Add test-fetestexceptflag.
	* math/test-fetestexceptflag.c: New file.
	* 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.

1 files changed, 6 insertions, 0 deletions

diff --git a/math/fenv.h b/math/fenv.h
index 7f4ceb744c..10d32db909 100644
--- a/math/fenv.h
+++ b/math/fenv.h
@@ -85,6 +85,12 @@ extern int fesetexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
    currently set.  */
 extern int fetestexcept (int __excepts) __THROW;
 
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Determine which of subset of the exceptions specified by EXCEPTS
+   are set in *FLAGP.  */
+extern int fetestexceptflag (const fexcept_t *__flagp, int __excepts) __THROW;
+#endif
+
 
 /* Rounding control.  */