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C++ GET_LOW_WORD函數代碼示例

本文整理匯總了C++中GET_LOW_WORD函數的典型用法代碼示例。如果您正苦於以下問題：C++ GET_LOW_WORD函數的具體用法？C++ GET_LOW_WORD怎麽用？C++ GET_LOW_WORD使用的例子？那麽, 這裏精選的函數代碼示例或許可以為您提供幫助。


在下文中一共展示了GET_LOW_WORD函數的15個代碼示例，這些例子默認根據受歡迎程度排序。您可以為喜歡或者感覺有用的代碼點讚，您的評價將有助於係統推薦出更棒的C++代碼示例。

示例1: __ieee754_exp10

double
__ieee754_exp10 (double arg)
{
  int32_t lx;
  double arg_high, arg_low;
  double exp_high, exp_low;

  if (!isfinite (arg))
    return __ieee754_exp (arg);
  if (arg < DBL_MIN_10_EXP - DBL_DIG - 10)
    return DBL_MIN * DBL_MIN;
  else if (arg > DBL_MAX_10_EXP + 1)
    return DBL_MAX * DBL_MAX;
  else if (fabs (arg) < 0x1p-56)
    return 1.0;

  GET_LOW_WORD (lx, arg);
  lx &= 0xf8000000;
  arg_high = arg;
  SET_LOW_WORD (arg_high, lx);
  arg_low = arg - arg_high;
  exp_high = arg_high * log10_high;
  exp_low = arg_high * log10_low + arg_low * M_LN10;
  return __ieee754_exp (exp_high) * __ieee754_exp (exp_low);
}
開發者ID:KubaKaszycki，項目名稱:kklibc，代碼行數:25，代碼來源:e_exp10.c

示例2: __ieee754_ilogb

int
__ieee754_ilogb (double x)
{
  int32_t hx, lx, ix;

  GET_HIGH_WORD (hx, x);
  hx &= 0x7fffffff;
  if (hx < 0x00100000)
    {
      GET_LOW_WORD (lx, x);
      if ((hx | lx) == 0)
	return FP_ILOGB0;               /* ilogb(0) = FP_ILOGB0 */
      else                              /* subnormal x */
      if (hx == 0)
	{
	  for (ix = -1043; lx > 0; lx <<= 1)
	    ix -= 1;
	}
      else
	{
	  for (ix = -1022, hx <<= 11; hx > 0; hx <<= 1)
	    ix -= 1;
	}
      return ix;
    }
  else if (hx < 0x7ff00000)
    return (hx >> 20) - 1023;
  else if (FP_ILOGBNAN != INT_MAX)
開發者ID:AubrCool，項目名稱:glibc，代碼行數:28，代碼來源:e_ilogb.c

示例3: atan

double atan(double x)
{
	double w,s1,s2,z;
	int32_t ix,hx,id;

	GET_HIGH_WORD(hx, x);
	ix = hx & 0x7fffffff;
	if (ix >= 0x44100000) {   /* if |x| >= 2^66 */
		uint32_t low;

		GET_LOW_WORD(low, x);
		if (ix > 0x7ff00000 ||
		    (ix == 0x7ff00000 && low != 0))  /* NaN */
			return x+x;
		if (hx > 0)
			return  atanhi[3] + *(volatile double *)&atanlo[3];
		else
			return -atanhi[3] - *(volatile double *)&atanlo[3];
	}
	if (ix < 0x3fdc0000) {    /* |x| < 0.4375 */
		if (ix < 0x3e400000) {  /* |x| < 2^-27 */
			/* raise inexact */
			if (huge+x > 1.0)
				return x;
		}
		id = -1;
	} else {
		x = fabs(x);
		if (ix < 0x3ff30000) {  /* |x| < 1.1875 */
			if (ix < 0x3fe60000) {  /*  7/16 <= |x| < 11/16 */
				id = 0;
				x = (2.0*x-1.0)/(2.0+x);
			} else {                /* 11/16 <= |x| < 19/16 */
				id = 1;
				x = (x-1.0)/(x+1.0);
			}
		} else {
			if (ix < 0x40038000) {  /* |x| < 2.4375 */
				id = 2;
				x = (x-1.5)/(1.0+1.5*x);
			} else {                /* 2.4375 <= |x| < 2^66 */
				id = 3;
				x = -1.0/x;
			}
		}
	}
	/* end of argument reduction */
	z = x*x;
	w = z*z;
	/* break sum from i=0 to 10 aT[i]z**(i+1) into odd and even poly */
	s1 = z*(aT[0]+w*(aT[2]+w*(aT[4]+w*(aT[6]+w*(aT[8]+w*aT[10])))));
	s2 = w*(aT[1]+w*(aT[3]+w*(aT[5]+w*(aT[7]+w*aT[9]))));
	if (id < 0)
		return x - x*(s1+s2);
	z = atanhi[id] - (x*(s1+s2) - atanlo[id] - x);
	return hx < 0 ? -z : z;
}
開發者ID:GregorR，項目名稱:musl，代碼行數:57，代碼來源:atan.c

示例4: acos

double acos(double x)
{
	double z, p, q, r, w, s, c, df;
	s32_t hx, ix;

	GET_HIGH_WORD(hx,x);
	ix = hx & 0x7fffffff;
	if (ix >= 0x3ff00000)
	{
		u32_t lx;
		GET_LOW_WORD(lx,x);
		if (((ix - 0x3ff00000) | lx) == 0)
		{
			if (hx > 0)
				return 0.0;
			else
				return pi + 2.0 * pio2_lo;
		}
		return (x - x) / (x - x);
	}
	if (ix < 0x3fe00000)
	{
		if (ix <= 0x3c600000)
			return pio2_hi + pio2_lo;
		z = x * x;
		p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
		q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
		r = p / q;
		return pio2_hi - (x - (pio2_lo - x * r));
	}
	else if (hx < 0)
	{
		z = (one + x) * 0.5;
		p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
		q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
		s = sqrt(z);
		r = p / q;
		w = r * s - pio2_lo;
		return pi - 2.0 * (s + w);
	}
	else
	{
		z = (one - x) * 0.5;
		s = sqrt(z);
		df = s;
		SET_LOW_WORD(df,0);
		c = (z - df * df) / (s + df);
		p = z * (pS0 + z * (pS1 + z * (pS2 + z * (pS3 + z * (pS4 + z * pS5)))));
		q = one + z * (qS1 + z * (qS2 + z * (qS3 + z * qS4)));
		r = p / q;
		w = r * s + c;
		return 2.0 * (df + w);
	}
}
開發者ID:rharter，項目名稱:xboot-clone，代碼行數:54，代碼來源:acos.c

示例5: __ieee754_cosh

double
__ieee754_cosh (double x)
{
  double t, w;
  int32_t ix;
  u_int32_t lx;

  /* High word of |x|. */
  GET_HIGH_WORD (ix, x);
  ix &= 0x7fffffff;

  /* |x| in [0,22] */
  if (ix < 0x40360000)
    {
      /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
      if (ix < 0x3fd62e43)
	{
	  if (ix < 0x3c800000)
	    return one;                                   /* cosh(tiny) = 1 */
	  t = __expm1 (fabs (x));
	  w = one + t;
	  return one + (t * t) / (w + w);
	}

      /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
      t = __ieee754_exp (fabs (x));
      return half * t + half / t;
    }

  /* |x| in [22, log(maxdouble)] return half*exp(|x|) */
  if (ix < 0x40862e42)
    return half * __ieee754_exp (fabs (x));

  /* |x| in [log(maxdouble), overflowthresold] */
  GET_LOW_WORD (lx, x);
  if (ix < 0x408633ce || ((ix == 0x408633ce) && (lx <= (u_int32_t) 0x8fb9f87d)))
    {
      w = __ieee754_exp (half * fabs (x));
      t = half * w;
      return t * w;
    }

  /* x is INF or NaN */
  if (ix >= 0x7ff00000)
    return x * x;

  /* |x| > overflowthresold, cosh(x) overflow */
  return huge * huge;
}
開發者ID:AubrCool，項目名稱:glibc，代碼行數:49，代碼來源:e_cosh.c

示例6: cbrt

double
cbrt(double x) 
{
	int32_t	hx;
	double r,s,t=0.0,w;
	u_int32_t sign;
	u_int32_t high,low;

	GET_HIGH_WORD(hx,x);
	sign=hx&0x80000000; 		/* sign= sign(x) */
	hx  ^=sign;
	if(hx>=0x7ff00000) return(x+x); /* cbrt(NaN,INF) is itself */
	GET_LOW_WORD(low,x);
	if((hx|low)==0) 
	    return(x);		/* cbrt(0) is itself */

	SET_HIGH_WORD(x,hx);	/* x <- |x| */
    /* rough cbrt to 5 bits */
	if(hx<0x00100000) 		/* subnormal number */
	  {SET_HIGH_WORD(t,0x43500000);	/* set t= 2**54 */
	   t*=x; GET_HIGH_WORD(high,t); SET_HIGH_WORD(t,high/3+B2);
	  }
	else
	  SET_HIGH_WORD(t,hx/3+B1);


    /* new cbrt to 23 bits, may be implemented in single precision */
	r=t*t/x;
	s=C+r*t;
	t*=G+F/(s+E+D/s);	

    /* chopped to 20 bits and make it larger than cbrt(x) */ 
	GET_HIGH_WORD(high,t);
	INSERT_WORDS(t,high+0x00000001,0);


    /* one step newton iteration to 53 bits with error less than 0.667 ulps */
	s=t*t;		/* t*t is exact */
	r=x/s;
	w=t+t;
	r=(r-t)/(w+r);	/* r-s is exact */
	t=t+t*r;

    /* retore the sign bit */
	GET_HIGH_WORD(high,t);
	SET_HIGH_WORD(t,high|sign);
	return(t);
}
開發者ID:SylvestreG，項目名稱:bitrig，代碼行數:48，代碼來源:s_cbrt.c

示例7: asin

double asin(double x)
{
	double t=0.0,w,p,q,c,r,s;
	int32_t hx,ix;

	GET_HIGH_WORD(hx, x);
	ix = hx & 0x7fffffff;
	if (ix >= 0x3ff00000) {           /* |x|>= 1 */
		uint32_t lx;

		GET_LOW_WORD(lx, x);
		if ((ix-0x3ff00000 | lx) == 0)
			/* asin(1) = +-pi/2 with inexact */
			return x*pio2_hi + x*pio2_lo;
		return (x-x)/(x-x);  /* asin(|x|>1) is NaN */
	} else if (ix < 0x3fe00000) {  /* |x|<0.5 */
		if (ix < 0x3e500000) {  /* if |x| < 2**-26 */
			if (huge+x > 1.0)
				return x; /* return x with inexact if x!=0*/
		}
		t = x*x;
		p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
		q = 1.0+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
		w = p/q;
		return x + x*w;
	}
	/* 1 > |x| >= 0.5 */
	w = 1.0 - fabs(x);
	t = w*0.5;
	p = t*(pS0+t*(pS1+t*(pS2+t*(pS3+t*(pS4+t*pS5)))));
	q = 1.0+t*(qS1+t*(qS2+t*(qS3+t*qS4)));
	s = sqrt(t);
	if (ix >= 0x3FEF3333) {  /* if |x| > 0.975 */
		w = p/q;
		t = pio2_hi-(2.0*(s+s*w)-pio2_lo);
	} else {
		w = s;
		SET_LOW_WORD(w,0);
		c = (t-w*w)/(s+w);
		r = p/q;
		p = 2.0*s*r-(pio2_lo-2.0*c);
		q = pio4_hi - 2.0*w;
		t = pio4_hi - (p-q);
	}
	if (hx > 0)
		return t;
	return -t;
}
開發者ID:GregorR，項目名稱:musl，代碼行數:48，代碼來源:asin.c

示例8: sin_pi

static double sin_pi(double x)
{
	double y,z;
	int n,ix;

	GET_HIGH_WORD(ix, x);
	ix &= 0x7fffffff;

	if (ix < 0x3fd00000)
		return __sin(pi*x, 0.0, 0);

	y = -x;  /* negative x is assumed */

	/*
	 * argument reduction, make sure inexact flag not raised if input
	 * is an integer
	 */
	z = floor(y);
	if (z != y) {    /* inexact anyway */
		y *= 0.5;
		y  = 2.0*(y - floor(y));   /* y = |x| mod 2.0 */
		n  = (int)(y*4.0);
	} else {
		if (ix >= 0x43400000) {
			y = 0.0;    /* y must be even */
			n = 0;
		} else {
			if (ix < 0x43300000)
				z = y + two52;  /* exact */
			GET_LOW_WORD(n, z);
			n &= 1;
			y = n;
			n <<= 2;
		}
	}
	switch (n) {
	case 0:  y =  __sin(pi*y, 0.0, 0); break;
	case 1:
	case 2:  y =  __cos(pi*(0.5-y), 0.0); break;
	case 3:
	case 4:  y =  __sin(pi*(1.0-y), 0.0, 0); break;
	case 5:
	case 6:  y = -__cos(pi*(y-1.5), 0.0); break;
	default: y =  __sin(pi*(y-2.0), 0.0, 0); break;
	}
	return -y;
}
開發者ID:EtchedPixels，項目名稱:FUZIX，代碼行數:47，代碼來源:lgamma_r.c

示例9: expm1

double
expm1(double x)
{
	double y,hi,lo,c,t,e,hxs,hfx,r1,twopk;
	int32_t k,xsb;
	uint32_t hx;

	GET_HIGH_WORD(hx,x);
	xsb = hx&0x80000000;		/* sign bit of x */
	hx &= 0x7fffffff;		/* high word of |x| */

    /* filter out huge and non-finite argument */
	if(hx >= 0x4043687A) {			/* if |x|>=56*ln2 */
	    if(hx >= 0x40862E42) {		/* if |x|>=709.78... */
                if(hx>=0x7ff00000) {
		    uint32_t low;
		    GET_LOW_WORD(low,x);
		    if(((hx&0xfffff)|low)!=0)
		         return x+x; 	 /* NaN */
		    else return (xsb==0)? x:-1.0;/* exp(+-inf)={inf,-1} */
	        }
	        if(x > o_threshold) return huge*huge; /* overflow */
	    }
	    if(xsb!=0) { /* x < -56*ln2, return -1.0 with inexact */
		if(x+tiny<0.0)		/* raise inexact */
		return tiny-one;	/* return -1 */
	    }
	}

    /* argument reduction */
	if(hx > 0x3fd62e42) {		/* if  |x| > 0.5 ln2 */
	    if(hx < 0x3FF0A2B2) {	/* and |x| < 1.5 ln2 */
		if(xsb==0)
		    {hi = x - ln2_hi; lo =  ln2_lo;  k =  1;}
		else
		    {hi = x + ln2_hi; lo = -ln2_lo;  k = -1;}
	    } else {
		k  = invln2*x+((xsb==0)?0.5:-0.5);
		t  = k;
		hi = x - t*ln2_hi;	/* t*ln2_hi is exact here */
		lo = t*ln2_lo;
	    }
	    STRICT_ASSIGN(double, x, hi - lo);
	    c  = (hi-x)-lo;
	}
	else if(hx < 0x3c900000) {  	/* when |x|<2**-54, return x */
開發者ID:SleepyBrett，項目名稱:electroportis，代碼行數:46，代碼來源:s_expm1.c

示例10: __ieee754_acos

double
__ieee754_acos(double x)
{
	double z, p, q, r, w, s, c, df;
	int32_t hx, ix;
	GET_HIGH_WORD(hx, x);
	ix = hx & 0x7fffffff;
	if (ix >= 0x3ff00000) {	/* |x| >= 1 */
		uint32_t lx;
		GET_LOW_WORD(lx, x);
		if (((ix - 0x3ff00000) | lx) == 0) {	/* |x|==1 */
			if (hx>0) return 0.0;		/* acos(1) = 0  */
			else return pi + 2.0*pio2_lo;	/* acos(-1)= pi */
		}
		return (x - x) / (x - x);		/* acos(|x|>1) is NaN */
	}
	if (ix<0x3fe00000) {	/* |x| < 0.5 */
		if (ix <= 0x3c600000) return pio2_hi + pio2_lo;/*if|x|<2**-57*/
		z = x*x;
		p = z*(pS0 + z*(pS1 + z*(pS2 + z*(pS3 + z*(pS4 + z*pS5)))));
		q = one + z*(qS1 + z*(qS2 + z*(qS3 + z*qS4)));
		r = p / q;
		return pio2_hi - (x - (pio2_lo - x*r));
	}
	else  if (hx<0) {		/* x < -0.5 */
		z = (one + x)*0.5;
		p = z*(pS0 + z*(pS1 + z*(pS2 + z*(pS3 + z*(pS4 + z*pS5)))));
		q = one + z*(qS1 + z*(qS2 + z*(qS3 + z*qS4)));
		s = sqrt(z);
		r = p / q;
		w = r*s - pio2_lo;
		return pi - 2.0*(s + w);
	}
	else {			/* x > 0.5 */
		z = (one - x)*0.5;
		s = sqrt(z);
		df = s;
		SET_LOW_WORD(df, 0);
		c = (z - df*df) / (s + df);
		p = z*(pS0 + z*(pS1 + z*(pS2 + z*(pS3 + z*(pS4 + z*pS5)))));
		q = one + z*(qS1 + z*(qS2 + z*(qS3 + z*qS4)));
		r = p / q;
		w = r*s + c;
		return 2.0*(df + w);
	}
}
開發者ID:Fadekraft，項目名稱:MollenOS，代碼行數:46，代碼來源:acos.c

示例11: ilogb

int ilogb(double x)
{
	int32_t hx,lx,ix;

	GET_HIGH_WORD(hx,x);
	hx &= 0x7fffffff;
	if(hx<0x00100000) {
	    GET_LOW_WORD(lx,x);
	    if((hx|lx)==0)
		return 0x80000001;	/* ilogb(0) = 0x80000001 */
	    else			/* subnormal x */
		if(hx==0) {
		    for (ix = -1043; lx>0; lx<<=1) ix -=1;
		} else {
		    for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;
		}
	    return ix;
	}
	else if (hx<0x7ff00000) return (hx>>20)-1023;
	else return 0x7fffffff;
開發者ID:OpenInkpot-archive，項目名稱:iplinux-uclibc，代碼行數:20，代碼來源:s_ilogb.c

示例12: cosh

double cosh(double x)
{
	double t, w;
	s32_t ix;
	u32_t lx;

	GET_HIGH_WORD(ix,x);
	ix &= 0x7fffffff;

	if (ix >= 0x7ff00000)
		return x * x;

	if (ix < 0x3fd62e43)
	{
		t = expm1(fabs(x));
		w = one + t;
		if (ix < 0x3c800000)
			return w;
		return one + (t * t) / (w + w);
	}

	if (ix < 0x40360000)
	{
		t = exp(fabs(x));
		return half * t + half / t;
	}

	if (ix < 0x40862E42)
		return half * exp(fabs(x));

	GET_LOW_WORD(lx,x);
	if (ix < 0x408633CE || ((ix == 0x408633ce)
			&& (lx <= (u32_t) 0x8fb9f87d)))
	{
		w = exp(half * fabs(x));
		t = half * w;
		return t * w;
	}

	return huge * huge;
}
開發者ID:cta08403，項目名稱:phoenixA20_linux_boot_sourcecode，代碼行數:41，代碼來源:cosh.c

示例13: __ieee754_sinh

double
__ieee754_sinh(double x)
{
	double t,w,h;
	int32_t ix,jx;
	uint32_t lx;

    /* High word of |x|. */
	GET_HIGH_WORD(jx,x);
	ix = jx&0x7fffffff;

    /* x is INF or NaN */
	if(ix>=0x7ff00000) return x+x;

	h = 0.5;
	if (jx<0) h = -h;
    /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
	if (ix < 0x40360000) {		/* |x|<22 */
	    if (ix<0x3e300000) 		/* |x|<2**-28 */
		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
	    t = expm1(fabs(x));
	    if(ix<0x3ff00000) return h*(2.0*t-t*t/(t+one));
	    return h*(t+t/(t+one));
	}

    /* |x| in [22, log(maxdouble)] return 0.5*exp(|x|) */
	if (ix < 0x40862E42)  return h*__ieee754_exp(fabs(x));

    /* |x| in [log(maxdouble), overflowthresold] */
	GET_LOW_WORD(lx,x);
	if (ix<0x408633CE || ((ix==0x408633ce)&&(lx<=(uint32_t)0x8fb9f87d))) {
	    w = __ieee754_exp(0.5*fabs(x));
	    t = h*w;
	    return t*w;
	}

    /* |x| > overflowthresold, sinh(x) overflow */
	return x*shuge;
}
開發者ID:Wannabe66，項目名稱:mx，代碼行數:39，代碼來源:e_sinh.c

示例14: __kernel_tan

	double __kernel_tan(double x, double y, int iy)
{
	double z,r,v,w,s;
	int32_t ix,hx;
	GET_HIGH_WORD(hx,x);
	ix = hx&0x7fffffff;	/* high word of |x| */
	if(ix<0x3e300000)			/* x < 2**-28 */
	    {if((int)x==0) {			/* generate inexact */
		u_int32_t low;
		GET_LOW_WORD(low,x);
		if(((ix|low)|(iy+1))==0) return one/fabs(x);
		else return (iy==1)? x: -one/x;
	    }
	    }
	if(ix>=0x3FE59428) { 			/* |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>=0x3FE59428) {
	    v = (double)iy;
	    return (double)(1-((hx>>30)&2))*(v-2.0*(x-(w*w/(w+v)-r)));
	}
開發者ID:ArcEye，項目名稱:RTAI-2，代碼行數:36，代碼來源:k_tan.c

示例15: exp2

/*
 * exp2(x): compute the base 2 exponential of x
 *
 * Accuracy: Peak error < 0.503 ulp for normalized results.
 *
 * Method: (accurate tables)
 *
 *   Reduce x:
 *     x = 2**k + y, for integer k and |y| <= 1/2.
 *     Thus we have exp2(x) = 2**k * exp2(y).
 *
 *   Reduce y:
 *     y = i/TBLSIZE + z - eps[i] for integer i near y * TBLSIZE.
 *     Thus we have exp2(y) = exp2(i/TBLSIZE) * exp2(z - eps[i]),
 *     with |z - eps[i]| <= 2**-9 + 2**-39 for the table used.
 *
 *   We compute exp2(i/TBLSIZE) via table lookup and exp2(z - eps[i]) via
 *   a degree-5 minimax polynomial with maximum error under 1.3 * 2**-61.
 *   The values in exp2t[] and eps[] are chosen such that
 *   exp2t[i] = exp2(i/TBLSIZE + eps[i]), and eps[i] is a small offset such
 *   that exp2t[i] is accurate to 2**-64.
 *
 *   Note that the range of i is +-TBLSIZE/2, so we actually index the tables
 *   by i0 = i + TBLSIZE/2.  For cache efficiency, exp2t[] and eps[] are
 *   virtual tables, interleaved in the real table tbl[].
 *
 *   This method is due to Gal, with many details due to Gal and Bachelis:
 *
 *      Gal, S. and Bachelis, B.  An Accurate Elementary Mathematical Library
 *      for the IEEE Floating Point Standard.  TOMS 17(1), 26-46 (1991).
 */
double exp2(double x)
{
	double r, t, z;
	uint32_t hx, ix, i0;
	union {uint32_t u; int32_t i;} k;

	/* Filter out exceptional cases. */
	GET_HIGH_WORD(hx, x);
	ix = hx & 0x7fffffff;
	if (ix >= 0x40900000) {        /* |x| >= 1024 */
		if (ix >= 0x7ff00000) {
			GET_LOW_WORD(ix, x);
			if (hx == 0xfff00000 && ix == 0) /* -inf */
				return 0;
			return x;
		}
		if (x >= 1024) {
			STRICT_ASSIGN(double, x, x * 0x1p1023);
			return x;
		}
		if (x <= -1075) {
			STRICT_ASSIGN(double, x, 0x1p-1000*0x1p-1000);
			return x;
		}
開發者ID:5kg，項目名稱:osv，代碼行數:55，代碼來源:exp2.c


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