GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libm/src/k_tanf.c Lines: 0 31 0.0 %
Date: 2017-11-13 Branches: 0 14 0.0 %

Line Branch Exec Source
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/* k_tanf.c -- float version of k_tan.c
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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 "math.h"
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#include "math_private.h"
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static const float
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one   =  1.0000000000e+00, /* 0x3f800000 */
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pio4  =  7.8539812565e-01, /* 0x3f490fda */
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pio4lo=  3.7748947079e-08, /* 0x33222168 */
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T[] =  {
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  3.3333334327e-01, /* 0x3eaaaaab */
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  1.3333334029e-01, /* 0x3e088889 */
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  5.3968254477e-02, /* 0x3d5d0dd1 */
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  2.1869488060e-02, /* 0x3cb327a4 */
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  8.8632395491e-03, /* 0x3c11371f */
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  3.5920790397e-03, /* 0x3b6b6916 */
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  1.4562094584e-03, /* 0x3abede48 */
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  5.8804126456e-04, /* 0x3a1a26c8 */
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  2.4646313977e-04, /* 0x398137b9 */
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  7.8179444245e-05, /* 0x38a3f445 */
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  7.1407252108e-05, /* 0x3895c07a */
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 -1.8558637748e-05, /* 0xb79bae5f */
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  2.5907305826e-05, /* 0x37d95384 */
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};
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float
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__kernel_tanf(float x, float y, int iy)
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{
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	float z,r,v,w,s;
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	int32_t ix,hx;
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	GET_FLOAT_WORD(hx,x);
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	ix = hx&0x7fffffff;	/* high word of |x| */
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	if(ix<0x31800000)			/* x < 2**-28 */
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	    {if((int)x==0) {			/* generate inexact */
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		if((ix|(iy+1))==0) return one/fabsf(x);
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		else return (iy==1)? x: -one/x;
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	    }
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	    }
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	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
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	    if(hx<0) {x = -x; y = -y;}
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	    z = pio4-x;
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	    w = pio4lo-y;
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	    x = z+w; y = 0.0;
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	}
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	z	=  x*x;
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	w 	=  z*z;
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    /* Break x^5*(T[1]+x^2*T[2]+...) into
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     *	  x^5(T[1]+x^4*T[3]+...+x^20*T[11]) +
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     *	  x^5(x^2*(T[2]+x^4*T[4]+...+x^22*[T12]))
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     */
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	r = T[1]+w*(T[3]+w*(T[5]+w*(T[7]+w*(T[9]+w*T[11]))));
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	v = z*(T[2]+w*(T[4]+w*(T[6]+w*(T[8]+w*(T[10]+w*T[12])))));
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	s = z*x;
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	r = y + z*(s*(r+v)+y);
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	r += T[0]*s;
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	w = x+r;
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	if(ix>=0x3f2ca140) {
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	    v = (float)iy;
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	    return (float)(1-((hx>>30)&2))*(v-(float)2.0*(x-(w*w/(w+v)-r)));
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	}
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	if(iy==1) return w;
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	else {		/* if allow error up to 2 ulp,
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			   simply return -1.0/(x+r) here */
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     /*  compute -1.0/(x+r) accurately */
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	    float a,t;
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	    int32_t i;
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	    z  = w;
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	    GET_FLOAT_WORD(i,z);
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	    SET_FLOAT_WORD(z,i&0xfffff000);
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	    v  = r-(z - x); 	/* z+v = r+x */
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	    t = a  = -(float)1.0/w;	/* a = -1.0/w */
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	    GET_FLOAT_WORD(i,t);
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	    SET_FLOAT_WORD(t,i&0xfffff000);
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	    s  = (float)1.0+t*z;
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	    return t+a*(s+t*v);
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	}
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}