Fix LP64 libm for 128-bit long doubles

* reworked amd64/_fpmath.h and arm64/_fpmath.h to support 128-bit long
doubles.
* improved tests to cover long double cases
* made modfl an alias for LP32

Tests pass on x86, x86_64, arm, arm64 and mips.

Bug: 12921273

Change-Id: Ibe39acde57972447a8950fa45b1e702acc68ebeb
diff --git a/libm/upstream-freebsd/lib/msun/ld128/s_nanl.c b/libm/upstream-freebsd/lib/msun/ld128/s_nanl.c
new file mode 100644
index 0000000..0f74a13
--- /dev/null
+++ b/libm/upstream-freebsd/lib/msun/ld128/s_nanl.c
@@ -0,0 +1,46 @@
+/*-
+ * Copyright (c) 2007 David Schultz
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <math.h>
+
+#include "fpmath.h"
+#include "../src/math_private.h"
+
+long double
+nanl(const char *s)
+{
+	union {
+		union IEEEl2bits ieee;
+		uint32_t bits[4];
+	} u;
+
+	_scan_nan(u.bits, 4, s);
+	u.ieee.bits.exp = 0x7fff;
+	u.ieee.bits.manh |= 1ULL << 47;	/* make it a quiet NaN */
+	return (u.ieee.e);
+}