1 /* from: FreeBSD: head/lib/msun/src/e_sinhl.c XXX */
2
3 /*
4 * ====================================================
5 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
6 *
7 * Developed at SunPro, a Sun Microsystems, Inc. business.
8 * Permission to use, copy, modify, and distribute this
9 * software is freely granted, provided that this notice
10 * is preserved.
11 * ====================================================
12 */
13
14 #include <sys/cdefs.h>
15 /*
16 * See e_sinh.c for complete comments.
17 *
18 * Converted to long double by Bruce D. Evans.
19 */
20
21 #include <float.h>
22 #ifdef __i386__
23 #include <ieeefp.h>
24 #endif
25
26 #include "fpmath.h"
27 #include "math.h"
28 #include "math_private.h"
29 #include "k_expl.h"
30
31 #if LDBL_MAX_EXP != 0x4000
32 /* We also require the usual expsign encoding. */
33 #error "Unsupported long double format"
34 #endif
35
36 #define BIAS (LDBL_MAX_EXP - 1)
37
38 static const long double shuge = 0x1p16383L;
39 #if LDBL_MANT_DIG == 64
40 /*
41 * Domain [-1, 1], range ~[-6.6749e-22, 6.6749e-22]:
42 * |sinh(x)/x - s(x)| < 2**-70.3
43 */
44 static const union IEEEl2bits
45 S3u = LD80C(0xaaaaaaaaaaaaaaaa, -3, 1.66666666666666666658e-1L);
46 #define S3 S3u.e
47 static const double
48 S5 = 8.3333333333333332e-3, /* 0x11111111111111.0p-59 */
49 S7 = 1.9841269841270074e-4, /* 0x1a01a01a01a070.0p-65 */
50 S9 = 2.7557319223873889e-6, /* 0x171de3a5565fe6.0p-71 */
51 S11 = 2.5052108406704084e-8, /* 0x1ae6456857530f.0p-78 */
52 S13 = 1.6059042748655297e-10, /* 0x161245fa910697.0p-85 */
53 S15 = 7.6470006914396920e-13, /* 0x1ae7ce4eff2792.0p-93 */
54 S17 = 2.8346142308424267e-15; /* 0x19882ce789ffc6.0p-101 */
55 #elif LDBL_MANT_DIG == 113
56 /*
57 * Domain [-1, 1], range ~[-2.9673e-36, 2.9673e-36]:
58 * |sinh(x)/x - s(x)| < 2**-118.0
59 */
60 static const long double
61 S3 = 1.66666666666666666666666666666666033e-1L, /* 0x1555555555555555555555555553b.0p-115L */
62 S5 = 8.33333333333333333333333333337643193e-3L, /* 0x111111111111111111111111180f5.0p-119L */
63 S7 = 1.98412698412698412698412697391263199e-4L, /* 0x1a01a01a01a01a01a01a0176aad11.0p-125L */
64 S9 = 2.75573192239858906525574406205464218e-6L, /* 0x171de3a556c7338faac243aaa9592.0p-131L */
65 S11 = 2.50521083854417187749675637460977997e-8L, /* 0x1ae64567f544e38fe59b3380d7413.0p-138L */
66 S13 = 1.60590438368216146368737762431552702e-10L, /* 0x16124613a86d098059c7620850fc2.0p-145L */
67 S15 = 7.64716373181980539786802470969096440e-13L, /* 0x1ae7f3e733b814193af09ce723043.0p-153L */
68 S17 = 2.81145725434775409870584280722701574e-15L; /* 0x1952c77030c36898c3fd0b6dfc562.0p-161L */
69 static const double
70 S19= 8.2206352435411005e-18, /* 0x12f49b4662b86d.0p-109 */
71 S21= 1.9572943931418891e-20, /* 0x171b8f2fab9628.0p-118 */
72 S23 = 3.8679983530666939e-23, /* 0x17617002b73afc.0p-127 */
73 S25 = 6.5067867911512749e-26; /* 0x1423352626048a.0p-136 */
74 #else
75 #error "Unsupported long double format"
76 #endif /* LDBL_MANT_DIG == 64 */
77
78 /* log(2**16385 - 0.5) rounded up: */
79 static const float
80 o_threshold = 1.13572168e4; /* 0xb174de.0p-10 */
81
82 long double
sinhl(long double x)83 sinhl(long double x)
84 {
85 long double hi,lo,x2,x4;
86 #if LDBL_MANT_DIG == 113
87 double dx2;
88 #endif
89 double s;
90 int16_t ix,jx;
91
92 GET_LDBL_EXPSIGN(jx,x);
93 ix = jx&0x7fff;
94
95 /* x is INF or NaN */
96 if(ix>=0x7fff) return x+x;
97
98 ENTERI();
99
100 s = 1;
101 if (jx<0) s = -1;
102
103 /* |x| < 64, return x, s(x), or accurate s*(exp(|x|)/2-1/exp(|x|)/2) */
104 if (ix<0x4005) { /* |x|<64 */
105 if (ix<BIAS-(LDBL_MANT_DIG+1)/2) /* |x|<TINY */
106 if(shuge+x>1) RETURNI(x); /* sinh(tiny) = tiny with inexact */
107 if (ix<0x3fff) { /* |x|<1 */
108 x2 = x*x;
109 #if LDBL_MANT_DIG == 64
110 x4 = x2*x2;
111 RETURNI(((S17*x2 + S15)*x4 + (S13*x2 + S11))*(x2*x*x4*x4) +
112 ((S9*x2 + S7)*x2 + S5)*(x2*x*x2) + S3*(x2*x) + x);
113 #elif LDBL_MANT_DIG == 113
114 dx2 = x2;
115 RETURNI(((((((((((S25*dx2 + S23)*dx2 +
116 S21)*x2 + S19)*x2 +
117 S17)*x2 + S15)*x2 + S13)*x2 + S11)*x2 + S9)*x2 + S7)*x2 +
118 S5)* (x2*x*x2) +
119 S3*(x2*x) + x);
120 #endif
121 }
122 k_hexpl(fabsl(x), &hi, &lo);
123 RETURNI(s*(lo - 0.25/(hi + lo) + hi));
124 }
125
126 /* |x| in [64, o_threshold], return correctly-overflowing s*exp(|x|)/2 */
127 if (fabsl(x) <= o_threshold)
128 RETURNI(s*hexpl(fabsl(x)));
129
130 /* |x| > o_threshold, sinh(x) overflow */
131 return x*shuge;
132 }
133