GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: lib/libm/src/s_expm1f.c Lines: 0 57 0.0 %
Date: 2017-11-13 Branches: 0 36 0.0 %

Line Branch Exec Source
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/* s_expm1f.c -- float version of s_expm1.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 volatile float huge = 1.0e+30, tiny = 1.0e-30;
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static const float
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one		= 1.0,
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o_threshold	= 8.8721679688e+01,/* 0x42b17180 */
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ln2_hi		= 6.9313812256e-01,/* 0x3f317180 */
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ln2_lo		= 9.0580006145e-06,/* 0x3717f7d1 */
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invln2		= 1.4426950216e+00,/* 0x3fb8aa3b */
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	/* scaled coefficients related to expm1 */
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Q1  =  -3.3333335072e-02, /* 0xbd088889 */
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Q2  =   1.5873016091e-03, /* 0x3ad00d01 */
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Q3  =  -7.9365076090e-05, /* 0xb8a670cd */
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Q4  =   4.0082177293e-06, /* 0x36867e54 */
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Q5  =  -2.0109921195e-07; /* 0xb457edbb */
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float
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expm1f(float x)
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{
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	float y,hi,lo,c,t,e,hxs,hfx,r1;
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	int32_t k,xsb;
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	u_int32_t hx;
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	GET_FLOAT_WORD(hx,x);
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	xsb = hx&0x80000000;		/* sign bit of x */
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	if(xsb==0) y=x; else y= -x;	/* y = |x| */
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	hx &= 0x7fffffff;		/* high word of |x| */
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    /* filter out huge and non-finite argument */
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	if(hx >= 0x4195b844) {			/* if |x|>=27*ln2 */
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	    if(hx >= 0x42b17218) {		/* if |x|>=88.721... */
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                if(hx>0x7f800000)
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		    return x+x; 	 /* NaN */
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		if(hx==0x7f800000)
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		    return (xsb==0)? x:-1.0;/* exp(+-inf)={inf,-1} */
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	        if(x > o_threshold) return huge*huge; /* overflow */
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	    }
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	    if(xsb!=0) { /* x < -27*ln2, return -1.0 with inexact */
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		if(x+tiny<(float)0.0)	/* raise inexact */
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		return tiny-one;	/* return -1 */
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	    }
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	}
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    /* argument reduction */
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	if(hx > 0x3eb17218) {		/* if  |x| > 0.5 ln2 */
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	    if(hx < 0x3F851592) {	/* and |x| < 1.5 ln2 */
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		if(xsb==0)
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		    {hi = x - ln2_hi; lo =  ln2_lo;  k =  1;}
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		else
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		    {hi = x + ln2_hi; lo = -ln2_lo;  k = -1;}
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	    } else {
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		k  = invln2*x+((xsb==0)?(float)0.5:(float)-0.5);
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		t  = k;
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		hi = x - t*ln2_hi;	/* t*ln2_hi is exact here */
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		lo = t*ln2_lo;
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	    }
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	    x  = hi - lo;
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	    c  = (hi-x)-lo;
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	}
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	else if(hx < 0x33000000) {  	/* when |x|<2**-25, return x */
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	    t = huge+x;	/* return x with inexact flags when x!=0 */
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	    return x - (t-(huge+x));
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	}
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	else k = 0;
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    /* x is now in primary range */
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	hfx = (float)0.5*x;
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	hxs = x*hfx;
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	r1 = one+hxs*(Q1+hxs*(Q2+hxs*(Q3+hxs*(Q4+hxs*Q5))));
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	t  = (float)3.0-r1*hfx;
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	e  = hxs*((r1-t)/((float)6.0 - x*t));
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	if(k==0) return x - (x*e-hxs);		/* c is 0 */
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	else {
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	    e  = (x*(e-c)-c);
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	    e -= hxs;
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	    if(k== -1) return (float)0.5*(x-e)-(float)0.5;
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	    if(k==1) {
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	       	if(x < (float)-0.25) return -(float)2.0*(e-(x+(float)0.5));
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	       	else 	      return  one+(float)2.0*(x-e);
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	    }
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	    if (k <= -2 || k>56) {   /* suffice to return exp(x)-1 */
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	        int32_t i;
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	        y = one-(e-x);
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		GET_FLOAT_WORD(i,y);
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		SET_FLOAT_WORD(y,i+(k<<23));	/* add k to y's exponent */
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	        return y-one;
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	    }
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	    t = one;
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	    if(k<23) {
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	        int32_t i;
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	        SET_FLOAT_WORD(t,0x3f800000 - (0x1000000>>k)); /* t=1-2^-k */
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	       	y = t-(e-x);
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		GET_FLOAT_WORD(i,y);
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		SET_FLOAT_WORD(y,i+(k<<23));	/* add k to y's exponent */
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	   } else {
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	        int32_t i;
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		SET_FLOAT_WORD(t,((0x7f-k)<<23));	/* 2^-k */
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	       	y = x-(e+t);
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	       	y += one;
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		GET_FLOAT_WORD(i,y);
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		SET_FLOAT_WORD(y,i+(k<<23));	/* add k to y's exponent */
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	    }
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	}
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	return y;
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}
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DEF_STD(expm1f);