65 lines
1.2 KiB
C
65 lines
1.2 KiB
C
/* _FSinh 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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static const float p[] = { /* courtesy Dr. Tim Prince */
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0.00020400F,
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0.00832983F,
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0.16666737F,
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0.99999998F};
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_CRTIMP2 float __cdecl _FSinh(float x, float y)
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{ /* compute y*sinh(x), |y| <= 1 */
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short neg;
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switch (_FDtest(&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 != 0.0F ? x : FSIGN(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 == 0.0F)
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return (x < 0.0F ? -y : y);
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if (x < 0.0F)
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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 < _FRteps._Float)
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x *= y; /* x tiny */
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else if (x < 1.0F)
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{
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float w = x * x;
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x += ((p[0] * w + p[1]) * w + p[2]) * w * x;
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x *= y;
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}
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else if (x < _FXbig)
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{ /* worth adding in exp(-x) */
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_FExp(&x, 1.0F, -1);
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x = y * (x - 0.25F / x);
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}
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else
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switch (_FExp(&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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