/*--------------------------------------------------------------------

 *© Portions copyright (c) 2006 Nokia Corporation.  All rights reserved.

 *--------------------------------------------------------------------

*/

/* s_erff.c -- float version of s_erf.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.

 * ====================================================

 */

#ifndef __SYMBIAN32__

#ifndef lint

static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_erff.c,v 1.7 2002/05/28 18:15:04 alfred Exp $";

#endif

#endif //__SYMBIAN32__

#include <math.h>

#include "math_private.h"

static const float

tiny	    = 1e-30,

half=  5.0000000000e-01, /* 0x3F000000 */

one =  1.0000000000e+00, /* 0x3F800000 */

two =  2.0000000000e+00, /* 0x40000000 */

	/* c = (subfloat)0.84506291151 */

erx =  8.4506291151e-01, /* 0x3f58560b */

/*

 * Coefficients for approximation to  erf on [0,0.84375]

 */

efx =  1.2837916613e-01, /* 0x3e0375d4 */

efx8=  1.0270333290e+00, /* 0x3f8375d4 */

pp0  =  1.2837916613e-01, /* 0x3e0375d4 */

pp1  = -3.2504209876e-01, /* 0xbea66beb */

pp2  = -2.8481749818e-02, /* 0xbce9528f */

pp3  = -5.7702702470e-03, /* 0xbbbd1489 */

pp4  = -2.3763017452e-05, /* 0xb7c756b1 */

qq1  =  3.9791721106e-01, /* 0x3ecbbbce */

qq2  =  6.5022252500e-02, /* 0x3d852a63 */

qq3  =  5.0813062117e-03, /* 0x3ba68116 */

qq4  =  1.3249473704e-04, /* 0x390aee49 */

qq5  = -3.9602282413e-06, /* 0xb684e21a */

/*

 * Coefficients for approximation to  erf  in [0.84375,1.25]

 */

pa0  = -2.3621185683e-03, /* 0xbb1acdc6 */

pa1  =  4.1485610604e-01, /* 0x3ed46805 */

pa2  = -3.7220788002e-01, /* 0xbebe9208 */

pa3  =  3.1834661961e-01, /* 0x3ea2fe54 */

pa4  = -1.1089469492e-01, /* 0xbde31cc2 */

pa5  =  3.5478305072e-02, /* 0x3d1151b3 */

pa6  = -2.1663755178e-03, /* 0xbb0df9c0 */

qa1  =  1.0642088205e-01, /* 0x3dd9f331 */

qa2  =  5.4039794207e-01, /* 0x3f0a5785 */

qa3  =  7.1828655899e-02, /* 0x3d931ae7 */

qa4  =  1.2617121637e-01, /* 0x3e013307 */

qa5  =  1.3637083583e-02, /* 0x3c5f6e13 */

qa6  =  1.1984500103e-02, /* 0x3c445aa3 */

/*

 * Coefficients for approximation to  erfc in [1.25,1/0.35]

 */

ra0  = -9.8649440333e-03, /* 0xbc21a093 */

ra1  = -6.9385856390e-01, /* 0xbf31a0b7 */

ra2  = -1.0558626175e+01, /* 0xc128f022 */

ra3  = -6.2375331879e+01, /* 0xc2798057 */

ra4  = -1.6239666748e+02, /* 0xc322658c */

ra5  = -1.8460508728e+02, /* 0xc3389ae7 */

ra6  = -8.1287437439e+01, /* 0xc2a2932b */

ra7  = -9.8143291473e+00, /* 0xc11d077e */

sa1  =  1.9651271820e+01, /* 0x419d35ce */

sa2  =  1.3765776062e+02, /* 0x4309a863 */

sa3  =  4.3456588745e+02, /* 0x43d9486f */

sa4  =  6.4538726807e+02, /* 0x442158c9 */

sa5  =  4.2900814819e+02, /* 0x43d6810b */

sa6  =  1.0863500214e+02, /* 0x42d9451f */

sa7  =  6.5702495575e+00, /* 0x40d23f7c */

sa8  = -6.0424413532e-02, /* 0xbd777f97 */

/*

 * Coefficients for approximation to  erfc in [1/.35,28]

 */

rb0  = -9.8649431020e-03, /* 0xbc21a092 */

rb1  = -7.9928326607e-01, /* 0xbf4c9dd4 */

rb2  = -1.7757955551e+01, /* 0xc18e104b */

rb3  = -1.6063638306e+02, /* 0xc320a2ea */

rb4  = -6.3756646729e+02, /* 0xc41f6441 */

rb5  = -1.0250950928e+03, /* 0xc480230b */

rb6  = -4.8351919556e+02, /* 0xc3f1c275 */

sb1  =  3.0338060379e+01, /* 0x41f2b459 */

sb2  =  3.2579251099e+02, /* 0x43a2e571 */

sb3  =  1.5367296143e+03, /* 0x44c01759 */

sb4  =  3.1998581543e+03, /* 0x4547fdbb */

sb5  =  2.5530502930e+03, /* 0x451f90ce */

sb6  =  4.7452853394e+02, /* 0x43ed43a7 */

sb7  = -2.2440952301e+01; /* 0xc1b38712 */

EXPORT_C float

erff(float x)

{

	int32_t hx,ix,i;

	float R,S,P,Q,s,y,z,r;

	GET_FLOAT_WORD(hx,x);

	ix = hx&0x7fffffff;

	if(ix>=0x7f800000) {		/* erf(nan)=nan */

	    i = ((u_int32_t)hx>>31)<<1;

	    return (float)(1-i)+one/x;	/* erf(+-inf)=+-1 */

	}

	if(ix < 0x3f580000) {		/* |x|<0.84375 */

	    if(ix < 0x31800000) { 	/* |x|<2**-28 */

	        if (ix < 0x04000000)

		    /*avoid underflow */

		    return (float)0.125*((float)8.0*x+efx8*x);

		return x + efx*x;

	    }

	    z = x*x;

	    r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));

	    s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));

	    y = r/s;

	    return x + x*y;

	}

	if(ix < 0x3fa00000) {		/* 0.84375 <= |x| < 1.25 */

	    s = fabsf(x)-one;

	    P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));

	    Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));

	    if(hx>=0) return erx + P/Q; else return -erx - P/Q;

	}

	if (ix >= 0x40c00000) {		/* inf>|x|>=6 */

	    if(hx>=0) return one-tiny; else return tiny-one;

	}

	x = fabsf(x);

 	s = one/(x*x);

	if(ix< 0x4036DB6E) {	/* |x| < 1/0.35 */

	    R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(

				ra5+s*(ra6+s*ra7))))));

	    S=one+s*(sa1+s*(sa2+s*(sa3+s*(sa4+s*(

				sa5+s*(sa6+s*(sa7+s*sa8)))))));

	} else {	/* |x| >= 1/0.35 */

	    R=rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(

				rb5+s*rb6)))));

	    S=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(

				sb5+s*(sb6+s*sb7))))));

	}

	GET_FLOAT_WORD(ix,x);

	SET_FLOAT_WORD(z,ix&0xfffff000);

	r  =  __ieee754_expf(-z*z-(float)0.5625)*__ieee754_expf((z-x)*(z+x)+R/S);

	if(hx>=0) return one-r/x; else return  r/x-one;

}

EXPORT_C float

erfcf(float x)

{

	int32_t hx,ix;

	float R,S,P,Q,s,y,z,r;

	GET_FLOAT_WORD(hx,x);

	ix = hx&0x7fffffff;

	if(ix>=0x7f800000) {			/* erfc(nan)=nan */

						/* erfc(+-inf)=0,2 */

	    return (float)(((u_int32_t)hx>>31)<<1)+one/x;

	}

	if(ix < 0x3f580000) {		/* |x|<0.84375 */

	    if(ix < 0x23800000)  	/* |x|<2**-56 */

		return one-x;

	    z = x*x;

	    r = pp0+z*(pp1+z*(pp2+z*(pp3+z*pp4)));

	    s = one+z*(qq1+z*(qq2+z*(qq3+z*(qq4+z*qq5))));

	    y = r/s;

	    if(hx < 0x3e800000) {  	/* x<1/4 */

		return one-(x+x*y);

	    } else {

		r = x*y;

		r += (x-half);

	        return half - r ;

	    }

	}

	if(ix < 0x3fa00000) {		/* 0.84375 <= |x| < 1.25 */

	    s = fabsf(x)-one;

	    P = pa0+s*(pa1+s*(pa2+s*(pa3+s*(pa4+s*(pa5+s*pa6)))));

	    Q = one+s*(qa1+s*(qa2+s*(qa3+s*(qa4+s*(qa5+s*qa6)))));

	    if(hx>=0) {

	        z  = one-erx; return z - P/Q;

	    } else {

		z = erx+P/Q; return one+z;

	    }

	}

	if (ix < 0x41e00000) {		/* |x|<28 */

	    x = fabsf(x);

 	    s = one/(x*x);

	    if(ix< 0x4036DB6D) {	/* |x| < 1/.35 ~ 2.857143*/

	        R=ra0+s*(ra1+s*(ra2+s*(ra3+s*(ra4+s*(

				ra5+s*(ra6+s*ra7))))));

	        S=one+s*(sa1+s*(sa2+s*(sa3+s*(sa4+s*(

				sa5+s*(sa6+s*(sa7+s*sa8)))))));

	    } else {			/* |x| >= 1/.35 ~ 2.857143 */

		if(hx<0&&ix>=0x40c00000) return two-tiny;/* x < -6 */

	        R=rb0+s*(rb1+s*(rb2+s*(rb3+s*(rb4+s*(

				rb5+s*rb6)))));

	        S=one+s*(sb1+s*(sb2+s*(sb3+s*(sb4+s*(

				sb5+s*(sb6+s*sb7))))));

	    }

	    GET_FLOAT_WORD(ix,x);

	    SET_FLOAT_WORD(z,ix&0xfffff000);

	    r  =  __ieee754_expf(-z*z-(float)0.5625)*

			__ieee754_expf((z-x)*(z+x)+R/S);

	    if(hx>0) return r/x; else return two-r/x;

	} else {

	    if(hx>0) return tiny*tiny; else return two-tiny;

	}

}