winsup/cygwin/math/tanhl.c

   1 /**
   2  * This file has no copyright assigned and is placed in the Public Domain.
   3  * This file is part of the mingw-w64 runtime package.
   4  * No warranty is given; refer to the file DISCLAIMER.PD within this package.
   5  */
   6 #include "cephes_mconf.h"
   7 #ifndef _SET_ERRNO
   8 #define _SET_ERRNO(x)
   9 #endif
  10
  11 #ifdef UNK
  12 static uLD P[] = {
  13   { { -6.8473739392677100872869E-5L } },
  14   { { -9.5658283111794641589011E-1L } },
  15   { { -8.4053568599672284488465E1L } },
  16   { { -1.3080425704712825945553E3L } }
  17 };
  18 static uLD Q[] = {
  19   { { 9.6259501838840336946872E1L } },
  20   { { 1.8218117903645559060232E3L } },
  21   { { 3.9241277114138477845780E3L } }
  22 };
  23 #endif
  24
  25 #ifdef IBMPC
  26 static uLD P[] = {
  27   { { 0xd2a4,0x1b0c,0x8f15,0x8f99,0xbff1, 0, 0, 0 } },
  28   { { 0x5959,0x9111,0x9cc7,0xf4e2,0xbffe, 0, 0, 0 } },
  29   { { 0xb576,0xef5e,0x6d57,0xa81b,0xc005, 0, 0, 0 } },
  30   { { 0xe3be,0xbfbd,0x5cbc,0xa381,0xc009, 0, 0, 0 } }
  31 };
  32 static uLD Q[] = {
  33   { { 0x687f,0xce24,0xdd6c,0xc084,0x4005, 0, 0, 0 } },
  34   { { 0x3793,0xc95f,0xfa2f,0xe3b9,0x4009, 0, 0, 0 } },
  35   { { 0xd5a2,0x1f9c,0x0b1b,0xf542,0x400a, 0, 0, 0 } }
  36 };
  37 #endif
  38
  39 #ifdef MIEEE
  40 static uLD P[] = {
  41   { { 0xbff10000,0x8f998f15,0x1b0cd2a4, 0 } },
  42   { { 0xbffe0000,0xf4e29cc7,0x91115959, 0 } },
  43   { { 0xc0050000,0xa81b6d57,0xef5eb576, 0 } },
  44   { { 0xc0090000,0xa3815cbc,0xbfbde3be, 0 } }
  45 };
  46 static uLD Q[] = {
  47   { { 0x40050000,0xc084dd6c,0xce24687f, 0 } },
  48   { { 0x40090000,0xe3b9fa2f,0xc95f3793, 0 } },
  49   { { 0x400a0000,0xf5420b1b,0x1f9cd5a2, 0 } }
  50 };
  51 #endif
  52
  53 long double tanhl(long double x)
  54 {
  55   long double s, z;
  56
  57 #ifdef MINUSZERO
  58   if (x == 0.0L)
  59     return (x);
  60 #endif
  61   if (isnanl(x))
  62   {
  63     _SET_ERRNO (EDOM);
  64     return x;
  65   }
  66
  67   z = fabsl(x);
  68   if (z > 0.5L * MAXLOGL)
  69   {
  70     _SET_ERRNO (ERANGE);
  71     if (x > 0)
  72       return (1.0L);
  73     else
  74       return (-1.0L);
  75   }
  76   if (z >= 0.625L)
  77   {
  78     s = expl(2.0*z);
  79     z =  1.0L  - 2.0/(s + 1.0L);
  80     if (x < 0)
  81       z = -z;
  82   }
  83   else
  84   {
  85     s = x * x;
  86     z = polevll( s, P, 3 )/p1evll(s, Q, 3);
  87     z = x * s * z;
  88     z = x + z;
  89   }
  90   return (z);
  91 }
  92