88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
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/* _LSinh function */
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#include "xmath.h"
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_STD_BEGIN
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/* coefficients */
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#define NP (sizeof (p) / sizeof (p[0]) - 1)
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#if _DLONG <= 1 /* assume IEEE 754 10 byte */
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static const long double p[] = { /* courtesy Dr. Tim Prince */
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0.0000000000000028486835L,
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0.0000000000007646464279L,
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0.0000000001605905091647L,
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0.0000000250521083436962L,
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0.0000027557319224130455L,
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0.0001984126984126956009L,
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0.0083333333333333336073L,
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0.1666666666666666666564L,
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1.0000000000000000000001L};
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#else /* assume IEEE 754 16 byte */
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static const long double p[] = { /* courtesy Dr. Tim Prince */
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0.00000000000000000000000006506911776L,
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0.00000000000000000000003867997525529L,
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0.00000000000000000001957294395545097L,
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0.00000000000000000822063524350084984L,
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0.00000000000000281145725434779709982L,
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0.00000000000076471637318198050919003L,
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0.00000000016059043836821614638343470L,
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0.00000002505210838544171877496283537L,
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0.00000275573192239858906525574505191L,
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0.00019841269841269841269841269726379L,
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0.00833333333333333333333333333338555L,
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0.16666666666666666666666666666666573L,
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1.0L};
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#endif
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_CRTIMP2 long double __cdecl _LSinh(long double x, long double y)
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{ /* compute y*sinh(x), |y| <= 1 */
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short neg;
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switch (_LDtest(&x))
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{ /* test for special codes */
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case _NANCODE:
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return (x);
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case _INFCODE:
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return (y != 0.0L ? x : LSIGN(x) ? -y : y);
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case 0:
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return (x * y);
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default: /* finite */
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if (y == 0.0L)
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return (x < 0.0L ? -y : y);
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if (x < 0.0L)
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x = -x, neg = 1;
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else
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neg = 0;
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if (x < _LRteps._Long_double)
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x *= y; /* x tiny */
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else if (x < 1.0L)
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{
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long double w = x * x;
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x += x * w * _LPoly(w, p, NP - 1);
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x *= y;
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}
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else if (x < _LXbig)
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{ /* worth adding in exp(-x) */
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_LExp(&x, 1.0L, -1);
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x = y * (x - 0.25L / x);
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}
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else
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switch (_LExp(&x, y, -1))
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{ /* report over/underflow */
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case 0:
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_Feraise(_FE_UNDERFLOW);
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break;
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case _INFCODE:
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_Feraise(_FE_OVERFLOW);
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}
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return (neg ? -x : x);
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}
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}
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_STD_END
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/*
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* Copyright (c) 1992-2001 by P.J. Plauger. ALL RIGHTS RESERVED.
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* Consult your license regarding permissions and restrictions.
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V3.10:0009 */
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