circuitpython/lib/libm/wf_tgamma.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* These math functions are taken from newlib-nano-2, the newlib/libm/math
* directory, available from https://github.com/32bitmicro/newlib-nano-2.
*
* Appropriate copyright headers are reproduced below.
*/
/* w_gammaf.c -- float version of w_gamma.c.
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "math.h"
#include "fdlibm.h"
#define _IEEE_LIBM 1
#ifdef __STDC__
float tgammaf(float x)
#else
float tgammaf(x)
float x;
#endif
{
float y;
int local_signgam;
if (!isfinite(x)) {
/* special cases: tgammaf(nan)=nan, tgammaf(inf)=inf, tgammaf(-inf)=nan */
return x + INFINITY;
}
y = expf(__ieee754_lgammaf_r(x,&local_signgam));
if (local_signgam < 0) y = -y;
#ifdef _IEEE_LIBM
return y;
#else
if(_LIB_VERSION == _IEEE_) return y;
if(!finitef(y)&&finitef(x)) {
if(floorf(x)==x&&x<=(float)0.0)
/* tgammaf pole */
return (float)__kernel_standard((double)x,(double)x,141);
else
/* tgammaf overflow */
return (float)__kernel_standard((double)x,(double)x,140);
}
return y;
#endif
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double tgamma(double x)
#else
double tgamma(x)
double x;
#endif
{
return (double) tgammaf((float) x);
}
#endif /* defined(_DOUBLE_IS_32BITS) */