mirror of
https://github.com/fluencelabs/musl
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44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
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/* origin: FreeBSD /usr/src/lib/msun/src/e_atanhf.c */
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/*
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#include "libm.h"
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static const float one = 1.0, huge = 1e30;
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static const float zero = 0.0;
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float atanhf(float x)
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{
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float t;
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int32_t hx,ix;
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GET_FLOAT_WORD(hx, x);
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ix = hx & 0x7fffffff;
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if (ix > 0x3f800000) /* |x| > 1 */
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return (x-x)/(x-x);
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if (ix == 0x3f800000)
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return x/zero;
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if (ix < 0x31800000 && huge+x > zero) /* x < 2**-28 */
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return x;
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SET_FLOAT_WORD(x, ix);
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if (ix < 0x3f000000) { /* x < 0.5 */
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t = x+x;
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t = (float)0.5*log1pf(t + t*x/(one-x));
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} else
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t = (float)0.5*log1pf((x+x)/(one-x));
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if (hx >= 0)
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return t;
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return -t;
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}
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