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Revision 1.7, Sun May 26 22:01:54 2002 UTC (21 years, 10 months ago) by wiz
Branch: MAIN
CVS Tags: yamt-pf42-baseX, yamt-pf42-base4, yamt-pf42-base3, yamt-pf42-base2, yamt-pf42-base, yamt-pf42, yamt-pagecache-tag8, yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, yamt-pagecache-base6, yamt-pagecache-base5, yamt-pagecache-base4, yamt-pagecache-base3, yamt-pagecache-base2, yamt-pagecache-base, yamt-pagecache, wrstuden-revivesa-base-3, wrstuden-revivesa-base-2, wrstuden-revivesa-base-1, wrstuden-revivesa-base, wrstuden-revivesa, wrstuden-fixsa-newbase, wrstuden-fixsa-base-1, wrstuden-fixsa-base, wrstuden-fixsa, tls-maxphys-base, tls-maxphys, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-3-RELEASE, netbsd-9-2-RELEASE, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, 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Changes since 1.6: +3 -11 lines

__STDC__ is always defined on NetBSD.

/* k_tanf.c -- float version of k_tan.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 <sys/cdefs.h>
#if defined(LIBM_SCCS) && !defined(lint)
__RCSID("$NetBSD: k_tanf.c,v 1.7 2002/05/26 22:01:54 wiz Exp $");
#endif

#include "math.h"
#include "math_private.h"
static const float
one   =  1.0000000000e+00, /* 0x3f800000 */
pio4  =  7.8539812565e-01, /* 0x3f490fda */
pio4lo=  3.7748947079e-08, /* 0x33222168 */
T[] =  {
  3.3333334327e-01, /* 0x3eaaaaab */
  1.3333334029e-01, /* 0x3e088889 */
  5.3968254477e-02, /* 0x3d5d0dd1 */
  2.1869488060e-02, /* 0x3cb327a4 */
  8.8632395491e-03, /* 0x3c11371f */
  3.5920790397e-03, /* 0x3b6b6916 */
  1.4562094584e-03, /* 0x3abede48 */
  5.8804126456e-04, /* 0x3a1a26c8 */
  2.4646313977e-04, /* 0x398137b9 */
  7.8179444245e-05, /* 0x38a3f445 */
  7.1407252108e-05, /* 0x3895c07a */
 -1.8558637748e-05, /* 0xb79bae5f */
  2.5907305826e-05, /* 0x37d95384 */
};

float
__kernel_tanf(float x, float y, int iy)
{
	float z,r,v,w,s;
	int32_t ix,hx;
	GET_FLOAT_WORD(hx,x);
	ix = hx&0x7fffffff;	/* high word of |x| */
	if(ix<0x31800000)			/* x < 2**-28 */
	    {if((int)x==0) {			/* generate inexact */
		if((ix|(iy+1))==0) return one/fabsf(x);
		else return (iy==1)? x: -one/x;
	    }
	    }
	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
	    if(hx<0) {x = -x; y = -y;}
	    z = pio4-x;
	    w = pio4lo-y;
	    x = z+w; y = 0.0;
	}
	z	=  x*x;
	w 	=  z*z;
    /* Break x^5*(T[1]+x^2*T[2]+...) into
     *	  x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
     *	  x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
     */
	r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
	v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
	s = z*x;
	r = y + z*(s*(r+v)+y);
	r += T[0]*s;
	w = x+r;
	if(ix>=0x3f2ca140) {
	    v = (float)iy;
	    return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r)));
	}
	if(iy==1) return w;
	else {		/* if allow error up to 2 ulp,
			   simply return -1.0/(x+r) here */
     /*  compute -1.0/(x+r) accurately */
	    float a,t;
	    int32_t i;
	    z  = w;
	    GET_FLOAT_WORD(i,z);
	    SET_FLOAT_WORD(z,i&0xfffff000);
	    v  = r-(z - x); 	/* z+v = r+x */
	    t = a  = -(float)1.0/w;	/* a = -1.0/w */
	    GET_FLOAT_WORD(i,t);
	    SET_FLOAT_WORD(t,i&0xfffff000);
	    s  = (float)1.0+t*z;
	    return t+a*(s+t*v);
	}
}