first commit of the new libm!

[musl] / src / math / asinhl.c

diff --git a/src/math/asinhl.c b/src/math/asinhl.c
new file mode 100644 (file)
index 0000000..b2edf90
--- /dev/null
+++ b/src/math/asinhl.c
@@ -0,0 +1,63 @@
+/* origin: OpenBSD /usr/src/lib/libm/src/ld80/s_asinhl.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.
+ * ====================================================
+ */
+/* asinhl(x)
+ * Method :
+ *      Based on
+ *              asinhl(x) = signl(x) * logl [ |x| + sqrtl(x*x+1) ]
+ *      we have
+ *      asinhl(x) := x  if  1+x*x=1,
+ *                := signl(x)*(logl(x)+ln2)) for large |x|, else
+ *                := signl(x)*logl(2|x|+1/(|x|+sqrtl(x*x+1))) if|x|>2, else
+ *                := signl(x)*log1pl(|x| + x^2/(1 + sqrtl(1+x^2)))
+ */
+
+#include "libm.h"
+
+#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
+long double asinhl(long double x)
+{
+       return asinh(x);
+}
+#elif LDBL_MANT_DIG == 64 && LDBL_MAX_EXP == 16384
+static const long double
+one  = 1.000000000000000000000e+00L, /* 0x3FFF, 0x00000000, 0x00000000 */
+ln2  = 6.931471805599453094287e-01L, /* 0x3FFE, 0xB17217F7, 0xD1CF79AC */
+huge = 1.000000000000000000e+4900L;
+
+long double asinhl(long double x)
+{
+       long double t,w;
+       int32_t hx,ix;
+
+       GET_LDOUBLE_EXP(hx, x);
+       ix = hx & 0x7fff;
+       if (ix == 0x7fff)
+               return x + x;   /* x is inf or NaN */
+       if (ix < 0x3fde) {      /* |x| < 2**-34 */
+               /* return x, raise inexact if x != 0 */
+               if (huge+x > one)
+                       return x;
+       }
+       if (ix > 0x4020) {      /* |x| > 2**34 */
+               w = logl(fabsl(x)) + ln2;
+       } else if (ix > 0x4000) { /* 2**34 > |x| > 2.0 */
+               t = fabsl(x);
+               w = logl(2.0*t + one/(sqrtl(x*x + one) + t));
+       } else {                /* 2.0 > |x| > 2**-28 */
+               t = x*x;
+               w =log1pl(fabsl(x) + t/(one + sqrtl(one + t)));
+       }
+       if (hx & 0x8000)
+               return -w;
+       return w;
+}
+#endif