float128: Add strtof128, wcstof128, and related functions.

The implementations are contained with sysdeps/ieee754/float128 as
they are only built when _Float128 is enabled within libc/m.

	* include/gmp.h (__mpn_construct_float128): New declaration.
	* include/stdlib.h: Include bits/floatn.h for _Float128 tests.
	(__strtof128_l): New declaration.
	(__strtof128_nan): Likewise.
	(__wcstof128_nan): Likewise.
	(__strtof128_internal): Likewise.
	(____strtof128_l_internal): Likewise.
	* include/wchar.h: Include bits/floatn.h for _Float128 tests.
	(__wcstof128_l): New declaration.
	(__wcstof128_internal): Likewise.

	* stdlib/Makefile (bug-strtod2): Link libm too.

	* stdlib/stdlib.h (strtof128): New declaration.
	(strtof128_l): Likewise.

	* stdlib/tst-strtod-nan-locale-main.c: Updated to use
	tst-strtod.h macros to ensure float128 gets tested too.

	* stdlib/tst-strtod-round-skeleton.c (CHOOSE_f128): New macro.

	* stdlib/tst-strtod.h: Include bits/floatn.h for _Float128
	tests.
	(IF_FLOAT128): New macro.
	(GEN_TEST_STRTOD): Update to optionally include _Float128 in
	the tests.
	(STRTOD_TEST_FOREACH): Likewise.

	* sysdeps/ieee754/float128/Makefile: Insert new strtof128 and
	wcstof128 functions into libc.

	* sysdeps/ieee754/float128/Versions: Add exports for the above
	new functions.

	* sysdeps/ieee754/float128/mpn2float128.c: New file.
	* sysdeps/ieee754/float128/strtod_nan_float128.h: New file.
	* sysdeps/ieee754/float128/strtof128.c: New file.
	* sysdeps/ieee754/float128/strtof128_l.c: New file.
	* sysdeps/ieee754/float128/strtof128_nan.c: New file.
	* sysdeps/ieee754/float128/wcstof128.c: New file.
	* sysdeps/ieee754/float128/wcstof128_l.c: New file.
	* sysdeps/ieee754/float128/wcstof128_nan.c: New fike.
	* wcsmbs/Makefile: (CFLAGS-wcstof128.c): Append strtox-CFLAGS.
	(CFLAGS-wcstof128_l): Likewise.

	* wcsmbs/wchar.h: Include bits/floatn.h for _Float128 tests.
	(wcstof128): New declaration.
	(wcstof128_l): Likewise.

1 files changed, 54 insertions, 0 deletions

diff --git a/sysdeps/ieee754/float128/mpn2float128.c b/sysdeps/ieee754/float128/mpn2float128.c
new file mode 100644
index 0000000000..12f703a757
--- /dev/null
+++ b/sysdeps/ieee754/float128/mpn2float128.c
@@ -0,0 +1,54 @@
+/* Convert a number in multi-precision format to _Float128.
+   Copyright (C) 2017 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 "gmp.h"
+#include "gmp-impl.h"
+#include <float.h>
+#include <math.h>
+
+#include "ieee754_float128.h"
+
+/* Convert a multi-precision integer of the needed number of bits (113 for
+   binary128) and an integral power of two to a `_Float128' in IEEE854
+   quad-precision format.  */
+
+_Float128
+__mpn_construct_float128 (mp_srcptr frac_ptr, int expt, int sign)
+{
+  union ieee854_float128 u;
+
+  u.ieee.negative = sign;
+  u.ieee.exponent = expt + IEEE854_FLOAT128_BIAS;
+#if BITS_PER_MP_LIMB == 32
+  u.ieee.mantissa3 = frac_ptr[0];
+  u.ieee.mantissa2 = frac_ptr[1];
+  u.ieee.mantissa1 = frac_ptr[2];
+  u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1
+				     << (FLT128_MANT_DIG - 96)) - 1);
+#elif BITS_PER_MP_LIMB == 64
+  u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa2 = frac_ptr[0] >> 32;
+  u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1);
+  u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1
+					     << (FLT128_MANT_DIG - 96)) - 1);
+#else
+  #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
+#endif
+
+  return u.d;
+}