Add setpayload, setpayloadf, setpayloadl.

TS 18661-1 defines functions for manipulating the payloads of NaNs.
This patch implements the setpayload functions for glibc; these set a
number (pointed to by a function argument) to a quiet NaN with the
given payload, or to +0 if the given payload is not valid.  The
implementations are structured to allow the substance of the
implementation to be shared with the setpayloadsig functions when
those are added.

The semantics in the TS are not entirely clear in the case where the
payload passed to the function is zero (see discussion on the WG14
reflector last month).  This patch implements what seems the most
sensible interpretation, that -0 is never valid to give as the
payload, but +0 is valid in the case where the kind of NaN being
generated has its high mantissa bit set so payload 0 is actually
possible in such a NaN.

Tested for x86_64, x86, mips64 and powerpc.

	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)]
	(setpayload): New declaration.
	* math/Versions (setpayload): New libm symbol at version
	GLIBC_2.25.
	(setpayloadf): Likewise.
	(setpayloadl): Likewise.
	* math/Makefile (libm-calls): Add s_setpayloadF.
	* math/libm-test.inc (struct test_Ffp_b1_data): Rename to struct
	test_Ff_b1_data.
	(RUN_TEST_Ff_b1): New macro.
	(RUN_TEST_LOOP_Ff_b1): Likewise.
	(canonicalize_test_data): Update type.
	(setpayload_test_data): New array.
	(setpayload_test): New function.
	(main): Call setpayload_test.
	* manual/arith.texi (FP Bit Twiddling): Document setpayload,
	setpayloadf and setpayloadl.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
	* sysdeps/ieee754/dbl-64/s_setpayload.c: New file.
	* sysdeps/ieee754/dbl-64/s_setpayload_main.c: Likewise.
	* sysdeps/ieee754/dbl-64/wordsize-64/s_setpayload_main.c:
	Likewise.
	* sysdeps/ieee754/flt-32/s_setpayloadf.c: Likewise.
	* sysdeps/ieee754/flt-32/s_setpayloadf_main.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_setpayloadl.c: Likewise.
	* sysdeps/ieee754/ldbl-128/s_setpayloadl_main.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_setpayloadl.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/s_setpayloadl_main.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_setpayloadl.c: Likewise.
	* sysdeps/ieee754/ldbl-96/s_setpayloadl_main.c: Likewise.
	* sysdeps/ieee754/ldbl-opt/nldbl-setpayload.c: Likewise.
	* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add
	setpayload.
	(CFLAGS-nldbl-setpayload.c): New variable.
	* 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.

2 files changed, 71 insertions, 0 deletions

diff --git a/sysdeps/ieee754/ldbl-96/s_setpayloadl.c b/sysdeps/ieee754/ldbl-96/s_setpayloadl.c
new file mode 100644
index 0000000000..1aba33e6e2
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-96/s_setpayloadl.c
@@ -0,0 +1,3 @@
+#define SIG 0
+#define FUNC setpayloadl
+#include <s_setpayloadl_main.c>
diff --git a/sysdeps/ieee754/ldbl-96/s_setpayloadl_main.c b/sysdeps/ieee754/ldbl-96/s_setpayloadl_main.c
new file mode 100644
index 0000000000..9af967b9f4
--- /dev/null
+++ b/sysdeps/ieee754/ldbl-96/s_setpayloadl_main.c
@@ -0,0 +1,68 @@
+/* Set NaN payload.  ldbl-96 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 <math.h>
+#include <math_private.h>
+#include <nan-high-order-bit.h>
+#include <stdint.h>
+
+#define SET_HIGH_BIT (HIGH_ORDER_BIT_IS_SET_FOR_SNAN ? SIG : !SIG)
+#define BIAS 0x3fff
+#define PAYLOAD_DIG 62
+#define EXPLICIT_MANT_DIG 63
+
+int
+FUNC (long double *x, long double payload)
+{
+  uint32_t hx, lx;
+  uint16_t exponent;
+  GET_LDOUBLE_WORDS (exponent, hx, lx, payload);
+  /* Test if argument is (a) negative or too large; (b) too small,
+     except for 0 when allowed; (c) not an integer.  */
+  if (exponent >= BIAS + PAYLOAD_DIG
+      || (exponent < BIAS && !(SET_HIGH_BIT
+			       && exponent == 0 && hx == 0 && lx == 0)))
+    {
+      SET_LDOUBLE_WORDS (*x, 0, 0, 0);
+      return 1;
+    }
+  int shift = BIAS + EXPLICIT_MANT_DIG - exponent;
+  if (shift < 32
+      ? (lx & ((1U << shift) - 1)) != 0
+      : (lx != 0 || (hx & ((1U << (shift - 32)) - 1)) != 0))
+    {
+      SET_LDOUBLE_WORDS (*x, 0, 0, 0);
+      return 1;
+    }
+  if (exponent != 0)
+    {
+      if (shift >= 32)
+	{
+	  lx = hx >> (shift - 32);
+	  hx = 0;
+	}
+      else if (shift != 0)
+	{
+	  lx = (lx >> shift) | (hx << (32 - shift));
+	  hx >>= shift;
+	}
+    }
+  hx |= 0x80000000 | (SET_HIGH_BIT ? 0x40000000 : 0);
+  SET_LDOUBLE_WORDS (*x, 0x7fff, hx, lx);
+  return 0;
+}