first commit of the new libm!

[musl] / src / math / sinhl.c

diff --git a/src/math/sinhl.c b/src/math/sinhl.c
new file mode 100644 (file)
index 0000000..2252dec
--- /dev/null
+++ b/src/math/sinhl.c
@@ -0,0 +1,81 @@
+/* origin: OpenBSD /usr/src/lib/libm/src/ld80/e_sinhl.c */
+/*
+ * ====================================================
+ * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
+ *
+ * Developed at SunPro, a Sun Microsystems, Inc. business.
+ * Permission to use, copy, modify, and distribute this
+ * software is freely granted, provided that this notice
+ * is preserved.
+ * ====================================================
+ */
+/* sinhl(x)
+ * Method :
+ * mathematically sinh(x) if defined to be (exp(x)-exp(-x))/2
+ *      1. Replace x by |x| (sinhl(-x) = -sinhl(x)).
+ *      2.
+ *                                                   E + E/(E+1)
+ *          0        <= x <= 25     :  sinhl(x) := --------------, E=expm1l(x)
+ *                                                       2
+ *
+ *          25       <= x <= lnovft :  sinhl(x) := expl(x)/2
+ *          lnovft   <= x <= ln2ovft:  sinhl(x) := expl(x/2)/2 * expl(x/2)
+ *          ln2ovft  <  x           :  sinhl(x) := x*huge (overflow)
+ *
+ * Special cases:
+ *      sinhl(x) is |x| if x is +INF, -INF, or NaN.
+ *      only sinhl(0)=0 is exact for finite x.
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double sinhl(long double x)
+{
+       return sinh(x);
+}
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+static const long double one = 1.0, huge = 1.0e4931L;
+
+long double sinhl(long double x)
+{
+       long double t,w,h;
+       uint32_t jx,ix,i0,i1;
+
+       /* Words of |x|. */
+       GET_LDOUBLE_WORDS(jx, i0, i1, x);
+       ix = jx & 0x7fff;
+
+       /* x is INF or NaN */
+       if (ix == 0x7fff) return x + x;
+
+       h = 0.5;
+       if (jx & 0x8000)
+               h = -h;
+       /* |x| in [0,25], return sign(x)*0.5*(E+E/(E+1))) */
+       if (ix < 0x4003 || (ix == 0x4003 && i0 <= 0xc8000000)) { /* |x| < 25 */
+               if (ix < 0x3fdf)  /* |x|<2**-32 */
+                       if (huge + x > one)
+                               return x;/* sinh(tiny) = tiny with inexact */
+               t = expm1l(fabsl(x));
+               if (ix < 0x3fff)
+                       return h*(2.0*t - t*t/(t + one));
+               return h*(t + t/(t + one));
+       }
+
+       /* |x| in [25, log(maxdouble)] return 0.5*exp(|x|) */
+       if (ix < 0x400c || (ix == 0x400c && i0 < 0xb17217f7))
+               return h*expl(fabsl(x));
+
+       /* |x| in [log(maxdouble), overflowthreshold] */
+       if (ix < 0x400c || (ix == 0x400c && (i0 < 0xb174ddc0 ||
+            (i0 == 0xb174ddc0 && i1 <= 0x31aec0ea)))) {
+               w = expl(0.5*fabsl(x));
+               t = h*w;
+               return t*w;
+       }
+
+       /* |x| > overflowthreshold, sinhl(x) overflow */
+       return x*huge;
+}
+#endif