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/k_sinl.c b/libm/upstream-freebsd/lib/msun/ld128/k_sinl.c
new file mode 100644
index 0000000..bd415c0
--- /dev/null
+++ b/libm/upstream-freebsd/lib/msun/ld128/k_sinl.c
@@ -0,0 +1,59 @@
+/* From: @(#)k_sin.c 1.3 95/01/18 */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ * Copyright (c) 2008 Steven G. Kargl, David Schultz, Bruce D. Evans.
+ *
+ * Developed at SunSoft, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+/*
+ * ld128 version of k_sin.c.  See ../src/k_sin.c for most comments.
+ */
+
+#include "math_private.h"
+
+static const double
+half =  0.5;
+
+/*
+ * Domain [-0.7854, 0.7854], range ~[-1.53e-37, 1.659e-37]
+ * |sin(x)/x - s(x)| < 2**-122.1
+ *
+ * See ../ld80/k_cosl.c for more details about the polynomial.
+ */
+static const long double
+S1 = -0.16666666666666666666666666666666666606732416116558L,
+S2 =  0.0083333333333333333333333333333331135404851288270047L,
+S3 = -0.00019841269841269841269841269839935785325638310428717L,
+S4 =  0.27557319223985890652557316053039946268333231205686e-5L,
+S5 = -0.25052108385441718775048214826384312253862930064745e-7L,
+S6 =  0.16059043836821614596571832194524392581082444805729e-9L,
+S7 = -0.76471637318198151807063387954939213287488216303768e-12L,
+S8 =  0.28114572543451292625024967174638477283187397621303e-14L;
+
+static const double
+S9  = -0.82206352458348947812512122163446202498005154296863e-17,
+S10 =  0.19572940011906109418080609928334380560135358385256e-19,
+S11 = -0.38680813379701966970673724299207480965452616911420e-22,
+S12 =  0.64038150078671872796678569586315881020659912139412e-25;
+
+long double
+__kernel_sinl(long double x, long double y, int iy)
+{
+	long double z,r,v;
+
+	z	=  x*x;
+	v	=  z*x;
+	r	=  S2+z*(S3+z*(S4+z*(S5+z*(S6+z*(S7+z*(S8+
+	    z*(S9+z*(S10+z*(S11+z*S12)))))))));
+	if(iy==0) return x+v*(S1+z*r);
+	else      return x-((z*(half*y-v*r)-y)-v*S1);
+}