src/video/e_pow.h
changeset 1895 c121d94672cb
parent 1424 7a610f25c12f
child 2752 edd2839b36f7
--- a/src/video/e_pow.h	Thu Jul 06 18:01:37 2006 +0000
+++ b/src/video/e_pow.h	Mon Jul 10 21:04:37 2006 +0000
@@ -67,236 +67,274 @@
 #else
 static double
 #endif
-bp[] = {1.0, 1.5,},
-dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */
-dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */
-	/* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */
-L1  =  5.99999999999994648725e-01, /* 0x3FE33333, 0x33333303 */
-L2  =  4.28571428578550184252e-01, /* 0x3FDB6DB6, 0xDB6FABFF */
-L3  =  3.33333329818377432918e-01, /* 0x3FD55555, 0x518F264D */
-L4  =  2.72728123808534006489e-01, /* 0x3FD17460, 0xA91D4101 */
-L5  =  2.30660745775561754067e-01, /* 0x3FCD864A, 0x93C9DB65 */
-L6  =  2.06975017800338417784e-01, /* 0x3FCA7E28, 0x4A454EEF */
-P1   =  1.66666666666666019037e-01, /* 0x3FC55555, 0x5555553E */
-P2   = -2.77777777770155933842e-03, /* 0xBF66C16C, 0x16BEBD93 */
-P3   =  6.61375632143793436117e-05, /* 0x3F11566A, 0xAF25DE2C */
-P4   = -1.65339022054652515390e-06, /* 0xBEBBBD41, 0xC5D26BF1 */
-P5   =  4.13813679705723846039e-08, /* 0x3E663769, 0x72BEA4D0 */
-lg2  =  6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
-lg2_h  =  6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */
-lg2_l  = -1.90465429995776804525e-09, /* 0xBE205C61, 0x0CA86C39 */
-ovt =  8.0085662595372944372e-0017, /* -(1024-log2(ovfl+.5ulp)) */
-cp    =  9.61796693925975554329e-01, /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */
-cp_h  =  9.61796700954437255859e-01, /* 0x3FEEC709, 0xE0000000 =(float)cp */
-cp_l  = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h*/
-ivln2    =  1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */
-ivln2_h  =  1.44269502162933349609e+00, /* 0x3FF71547, 0x60000000 =24b 1/ln2*/
-ivln2_l  =  1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
+  bp[] = { 1.0, 1.5, }, dp_h[] = {
+0.0, 5.84962487220764160156e-01,},      /* 0x3FE2B803, 0x40000000 */
+
+    dp_l[] = {
+0.0, 1.35003920212974897128e-08,},      /* 0x3E4CFDEB, 0x43CFD006 */
+
+    /* poly coefs for (3/2)*(log(x)-2s-2/3*s**3 */
+    L1 = 5.99999999999994648725e-01,    /* 0x3FE33333, 0x33333303 */
+    L2 = 4.28571428578550184252e-01,    /* 0x3FDB6DB6, 0xDB6FABFF */
+    L3 = 3.33333329818377432918e-01,    /* 0x3FD55555, 0x518F264D */
+    L4 = 2.72728123808534006489e-01,    /* 0x3FD17460, 0xA91D4101 */
+    L5 = 2.30660745775561754067e-01,    /* 0x3FCD864A, 0x93C9DB65 */
+    L6 = 2.06975017800338417784e-01,    /* 0x3FCA7E28, 0x4A454EEF */
+    P1 = 1.66666666666666019037e-01,    /* 0x3FC55555, 0x5555553E */
+    P2 = -2.77777777770155933842e-03,   /* 0xBF66C16C, 0x16BEBD93 */
+    P3 = 6.61375632143793436117e-05,    /* 0x3F11566A, 0xAF25DE2C */
+    P4 = -1.65339022054652515390e-06,   /* 0xBEBBBD41, 0xC5D26BF1 */
+    P5 = 4.13813679705723846039e-08,    /* 0x3E663769, 0x72BEA4D0 */
+    lg2 = 6.93147180559945286227e-01,   /* 0x3FE62E42, 0xFEFA39EF */
+    lg2_h = 6.93147182464599609375e-01, /* 0x3FE62E43, 0x00000000 */
+    lg2_l = -1.90465429995776804525e-09,        /* 0xBE205C61, 0x0CA86C39 */
+    ovt = 8.0085662595372944372e-0017,  /* -(1024-log2(ovfl+.5ulp)) */
+    cp = 9.61796693925975554329e-01,    /* 0x3FEEC709, 0xDC3A03FD =2/(3ln2) */
+    cp_h = 9.61796700954437255859e-01,  /* 0x3FEEC709, 0xE0000000 =(float)cp */
+    cp_l = -7.02846165095275826516e-09, /* 0xBE3E2FE0, 0x145B01F5 =tail of cp_h */
+    ivln2 = 1.44269504088896338700e+00, /* 0x3FF71547, 0x652B82FE =1/ln2 */
+    ivln2_h = 1.44269502162933349609e+00,       /* 0x3FF71547, 0x60000000 =24b 1/ln2 */
+    ivln2_l = 1.92596299112661746887e-08;       /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail */
 
 #ifdef __STDC__
-	double __ieee754_pow(double x, double y)
+double
+__ieee754_pow(double x, double y)
 #else
-	double __ieee754_pow(x,y)
-	double x, y;
+double
+__ieee754_pow(x, y)
+     double x, y;
 #endif
 {
-	double z,ax,z_h,z_l,p_h,p_l;
-	double y1,t1,t2,r,s,t,u,v,w;
-	int32_t i,j,k,yisint,n;
-	int32_t hx,hy,ix,iy;
-	u_int32_t lx,ly;
+    double z, ax, z_h, z_l, p_h, p_l;
+    double y1, t1, t2, r, s, t, u, v, w;
+    int32_t i, j, k, yisint, n;
+    int32_t hx, hy, ix, iy;
+    u_int32_t lx, ly;
 
-	EXTRACT_WORDS(hx,lx,x);
-	EXTRACT_WORDS(hy,ly,y);
-	ix = hx&0x7fffffff;  iy = hy&0x7fffffff;
+    EXTRACT_WORDS(hx, lx, x);
+    EXTRACT_WORDS(hy, ly, y);
+    ix = hx & 0x7fffffff;
+    iy = hy & 0x7fffffff;
 
     /* y==zero: x**0 = 1 */
-	if((iy|ly)==0) return one;
+    if ((iy | ly) == 0)
+        return one;
 
     /* +-NaN return x+y */
-	if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
-	   iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0)))
-		return x+y;
+    if (ix > 0x7ff00000 || ((ix == 0x7ff00000) && (lx != 0)) ||
+        iy > 0x7ff00000 || ((iy == 0x7ff00000) && (ly != 0)))
+        return x + y;
 
     /* determine if y is an odd int when x < 0
-     * yisint = 0	... y is not an integer
-     * yisint = 1	... y is an odd int
-     * yisint = 2	... y is an even int
+     * yisint = 0       ... y is not an integer
+     * yisint = 1       ... y is an odd int
+     * yisint = 2       ... y is an even int
      */
-	yisint  = 0;
-	if(hx<0) {
-	    if(iy>=0x43400000) yisint = 2; /* even integer y */
-	    else if(iy>=0x3ff00000) {
-		k = (iy>>20)-0x3ff;	   /* exponent */
-		if(k>20) {
-		    j = ly>>(52-k);
-		    if((u_int32_t)(j<<(52-k))==ly) yisint = 2-(j&1);
-		} else if(ly==0) {
-		    j = iy>>(20-k);
-		    if((j<<(20-k))==iy) yisint = 2-(j&1);
-		}
-	    }
-	}
+    yisint = 0;
+    if (hx < 0) {
+        if (iy >= 0x43400000)
+            yisint = 2;         /* even integer y */
+        else if (iy >= 0x3ff00000) {
+            k = (iy >> 20) - 0x3ff;     /* exponent */
+            if (k > 20) {
+                j = ly >> (52 - k);
+                if ((u_int32_t) (j << (52 - k)) == ly)
+                    yisint = 2 - (j & 1);
+            } else if (ly == 0) {
+                j = iy >> (20 - k);
+                if ((j << (20 - k)) == iy)
+                    yisint = 2 - (j & 1);
+            }
+        }
+    }
 
     /* special value of y */
-	if(ly==0) {
-	    if (iy==0x7ff00000) {	/* y is +-inf */
-	        if(((ix-0x3ff00000)|lx)==0)
-		    return  y - y;	/* inf**+-1 is NaN */
-	        else if (ix >= 0x3ff00000)/* (|x|>1)**+-inf = inf,0 */
-		    return (hy>=0)? y: zero;
-	        else			/* (|x|<1)**-,+inf = inf,0 */
-		    return (hy<0)?-y: zero;
-	    }
-	    if(iy==0x3ff00000) {	/* y is  +-1 */
-		if(hy<0) return one/x; else return x;
-	    }
-	    if(hy==0x40000000) return x*x; /* y is  2 */
-	    if(hy==0x3fe00000) {	/* y is  0.5 */
-		if(hx>=0)	/* x >= +0 */
-		return __ieee754_sqrt(x);
-	    }
-	}
+    if (ly == 0) {
+        if (iy == 0x7ff00000) { /* y is +-inf */
+            if (((ix - 0x3ff00000) | lx) == 0)
+                return y - y;   /* inf**+-1 is NaN */
+            else if (ix >= 0x3ff00000)  /* (|x|>1)**+-inf = inf,0 */
+                return (hy >= 0) ? y : zero;
+            else                /* (|x|<1)**-,+inf = inf,0 */
+                return (hy < 0) ? -y : zero;
+        }
+        if (iy == 0x3ff00000) { /* y is  +-1 */
+            if (hy < 0)
+                return one / x;
+            else
+                return x;
+        }
+        if (hy == 0x40000000)
+            return x * x;       /* y is  2 */
+        if (hy == 0x3fe00000) { /* y is  0.5 */
+            if (hx >= 0)        /* x >= +0 */
+                return __ieee754_sqrt(x);
+        }
+    }
 
-	ax   = x < 0 ? -x : x; /*fabs(x);*/
+    ax = x < 0 ? -x : x;        /*fabs(x); */
     /* special value of x */
-	if(lx==0) {
-	    if(ix==0x7ff00000||ix==0||ix==0x3ff00000){
-		z = ax;			/*x is +-0,+-inf,+-1*/
-		if(hy<0) z = one/z;	/* z = (1/|x|) */
-		if(hx<0) {
-		    if(((ix-0x3ff00000)|yisint)==0) {
-			z = (z-z)/(z-z); /* (-1)**non-int is NaN */
-		    } else if(yisint==1)
-			z = -z;		/* (x<0)**odd = -(|x|**odd) */
-		}
-		return z;
-	    }
-	}
+    if (lx == 0) {
+        if (ix == 0x7ff00000 || ix == 0 || ix == 0x3ff00000) {
+            z = ax;             /*x is +-0,+-inf,+-1 */
+            if (hy < 0)
+                z = one / z;    /* z = (1/|x|) */
+            if (hx < 0) {
+                if (((ix - 0x3ff00000) | yisint) == 0) {
+                    z = (z - z) / (z - z);      /* (-1)**non-int is NaN */
+                } else if (yisint == 1)
+                    z = -z;     /* (x<0)**odd = -(|x|**odd) */
+            }
+            return z;
+        }
+    }
 
     /* (x<0)**(non-int) is NaN */
-	if(((((u_int32_t)hx>>31)-1)|yisint)==0) return (x-x)/(x-x);
+    if (((((u_int32_t) hx >> 31) - 1) | yisint) == 0)
+        return (x - x) / (x - x);
 
     /* |y| is huge */
-	if(iy>0x41e00000) { /* if |y| > 2**31 */
-	    if(iy>0x43f00000){	/* if |y| > 2**64, must o/uflow */
-		if(ix<=0x3fefffff) return (hy<0)? huge*huge:tiny*tiny;
-		if(ix>=0x3ff00000) return (hy>0)? huge*huge:tiny*tiny;
-	    }
-	/* over/underflow if x is not close to one */
-	    if(ix<0x3fefffff) return (hy<0)? huge*huge:tiny*tiny;
-	    if(ix>0x3ff00000) return (hy>0)? huge*huge:tiny*tiny;
-	/* now |1-x| is tiny <= 2**-20, suffice to compute
-	   log(x) by x-x^2/2+x^3/3-x^4/4 */
-	    t = x-1;		/* t has 20 trailing zeros */
-	    w = (t*t)*(0.5-t*(0.3333333333333333333333-t*0.25));
-	    u = ivln2_h*t;	/* ivln2_h has 21 sig. bits */
-	    v = t*ivln2_l-w*ivln2;
-	    t1 = u+v;
-	    SET_LOW_WORD(t1,0);
-	    t2 = v-(t1-u);
-	} else {
-	    double s2,s_h,s_l,t_h,t_l;
-	    n = 0;
-	/* take care subnormal number */
-	    if(ix<0x00100000)
-		{ax *= two53; n -= 53; GET_HIGH_WORD(ix,ax); }
-	    n  += ((ix)>>20)-0x3ff;
-	    j  = ix&0x000fffff;
-	/* determine interval */
-	    ix = j|0x3ff00000;		/* normalize ix */
-	    if(j<=0x3988E) k=0;		/* |x|<sqrt(3/2) */
-	    else if(j<0xBB67A) k=1;	/* |x|<sqrt(3)   */
-	    else {k=0;n+=1;ix -= 0x00100000;}
-	    SET_HIGH_WORD(ax,ix);
+    if (iy > 0x41e00000) {      /* if |y| > 2**31 */
+        if (iy > 0x43f00000) {  /* if |y| > 2**64, must o/uflow */
+            if (ix <= 0x3fefffff)
+                return (hy < 0) ? huge * huge : tiny * tiny;
+            if (ix >= 0x3ff00000)
+                return (hy > 0) ? huge * huge : tiny * tiny;
+        }
+        /* over/underflow if x is not close to one */
+        if (ix < 0x3fefffff)
+            return (hy < 0) ? huge * huge : tiny * tiny;
+        if (ix > 0x3ff00000)
+            return (hy > 0) ? huge * huge : tiny * tiny;
+        /* now |1-x| is tiny <= 2**-20, suffice to compute
+           log(x) by x-x^2/2+x^3/3-x^4/4 */
+        t = x - 1;              /* t has 20 trailing zeros */
+        w = (t * t) * (0.5 - t * (0.3333333333333333333333 - t * 0.25));
+        u = ivln2_h * t;        /* ivln2_h has 21 sig. bits */
+        v = t * ivln2_l - w * ivln2;
+        t1 = u + v;
+        SET_LOW_WORD(t1, 0);
+        t2 = v - (t1 - u);
+    } else {
+        double s2, s_h, s_l, t_h, t_l;
+        n = 0;
+        /* take care subnormal number */
+        if (ix < 0x00100000) {
+            ax *= two53;
+            n -= 53;
+            GET_HIGH_WORD(ix, ax);
+        }
+        n += ((ix) >> 20) - 0x3ff;
+        j = ix & 0x000fffff;
+        /* determine interval */
+        ix = j | 0x3ff00000;    /* normalize ix */
+        if (j <= 0x3988E)
+            k = 0;              /* |x|<sqrt(3/2) */
+        else if (j < 0xBB67A)
+            k = 1;              /* |x|<sqrt(3)   */
+        else {
+            k = 0;
+            n += 1;
+            ix -= 0x00100000;
+        }
+        SET_HIGH_WORD(ax, ix);
 
-	/* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */
-	    u = ax-bp[k];		/* bp[0]=1.0, bp[1]=1.5 */
-	    v = one/(ax+bp[k]);
-	    s = u*v;
-	    s_h = s;
-	    SET_LOW_WORD(s_h,0);
-	/* t_h=ax+bp[k] High */
-	    t_h = zero;
-	    SET_HIGH_WORD(t_h,((ix>>1)|0x20000000)+0x00080000+(k<<18));
-	    t_l = ax - (t_h-bp[k]);
-	    s_l = v*((u-s_h*t_h)-s_h*t_l);
-	/* compute log(ax) */
-	    s2 = s*s;
-	    r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6)))));
-	    r += s_l*(s_h+s);
-	    s2  = s_h*s_h;
-	    t_h = 3.0+s2+r;
-	    SET_LOW_WORD(t_h,0);
-	    t_l = r-((t_h-3.0)-s2);
-	/* u+v = s*(1+...) */
-	    u = s_h*t_h;
-	    v = s_l*t_h+t_l*s;
-	/* 2/(3log2)*(s+...) */
-	    p_h = u+v;
-	    SET_LOW_WORD(p_h,0);
-	    p_l = v-(p_h-u);
-	    z_h = cp_h*p_h;		/* cp_h+cp_l = 2/(3*log2) */
-	    z_l = cp_l*p_h+p_l*cp+dp_l[k];
-	/* log2(ax) = (s+..)*2/(3*log2) = n + dp_h + z_h + z_l */
-	    t = (double)n;
-	    t1 = (((z_h+z_l)+dp_h[k])+t);
-	    SET_LOW_WORD(t1,0);
-	    t2 = z_l-(((t1-t)-dp_h[k])-z_h);
-	}
+        /* compute s = s_h+s_l = (x-1)/(x+1) or (x-1.5)/(x+1.5) */
+        u = ax - bp[k];         /* bp[0]=1.0, bp[1]=1.5 */
+        v = one / (ax + bp[k]);
+        s = u * v;
+        s_h = s;
+        SET_LOW_WORD(s_h, 0);
+        /* t_h=ax+bp[k] High */
+        t_h = zero;
+        SET_HIGH_WORD(t_h, ((ix >> 1) | 0x20000000) + 0x00080000 + (k << 18));
+        t_l = ax - (t_h - bp[k]);
+        s_l = v * ((u - s_h * t_h) - s_h * t_l);
+        /* compute log(ax) */
+        s2 = s * s;
+        r = s2 * s2 * (L1 +
+                       s2 * (L2 +
+                             s2 * (L3 + s2 * (L4 + s2 * (L5 + s2 * L6)))));
+        r += s_l * (s_h + s);
+        s2 = s_h * s_h;
+        t_h = 3.0 + s2 + r;
+        SET_LOW_WORD(t_h, 0);
+        t_l = r - ((t_h - 3.0) - s2);
+        /* u+v = s*(1+...) */
+        u = s_h * t_h;
+        v = s_l * t_h + t_l * s;
+        /* 2/(3log2)*(s+...) */
+        p_h = u + v;
+        SET_LOW_WORD(p_h, 0);
+        p_l = v - (p_h - u);
+        z_h = cp_h * p_h;       /* cp_h+cp_l = 2/(3*log2) */
+        z_l = cp_l * p_h + p_l * cp + dp_l[k];
+        /* log2(ax) = (s+..)*2/(3*log2) = n + dp_h + z_h + z_l */
+        t = (double) n;
+        t1 = (((z_h + z_l) + dp_h[k]) + t);
+        SET_LOW_WORD(t1, 0);
+        t2 = z_l - (((t1 - t) - dp_h[k]) - z_h);
+    }
 
-	s = one; /* s (sign of result -ve**odd) = -1 else = 1 */
-	if(((((u_int32_t)hx>>31)-1)|(yisint-1))==0)
-	    s = -one;/* (-ve)**(odd int) */
+    s = one;                    /* s (sign of result -ve**odd) = -1 else = 1 */
+    if (((((u_int32_t) hx >> 31) - 1) | (yisint - 1)) == 0)
+        s = -one;               /* (-ve)**(odd int) */
 
     /* split up y into y1+y2 and compute (y1+y2)*(t1+t2) */
-	y1  = y;
-	SET_LOW_WORD(y1,0);
-	p_l = (y-y1)*t1+y*t2;
-	p_h = y1*t1;
-	z = p_l+p_h;
-	EXTRACT_WORDS(j,i,z);
-	if (j>=0x40900000) {				/* z >= 1024 */
-	    if(((j-0x40900000)|i)!=0)			/* if z > 1024 */
-		return s*huge*huge;			/* overflow */
-	    else {
-		if(p_l+ovt>z-p_h) return s*huge*huge;	/* overflow */
-	    }
-	} else if((j&0x7fffffff)>=0x4090cc00 ) {	/* z <= -1075 */
-	    if(((j-0xc090cc00)|i)!=0) 		/* z < -1075 */
-		return s*tiny*tiny;		/* underflow */
-	    else {
-		if(p_l<=z-p_h) return s*tiny*tiny;	/* underflow */
-	    }
-	}
+    y1 = y;
+    SET_LOW_WORD(y1, 0);
+    p_l = (y - y1) * t1 + y * t2;
+    p_h = y1 * t1;
+    z = p_l + p_h;
+    EXTRACT_WORDS(j, i, z);
+    if (j >= 0x40900000) {      /* z >= 1024 */
+        if (((j - 0x40900000) | i) != 0)        /* if z > 1024 */
+            return s * huge * huge;     /* overflow */
+        else {
+            if (p_l + ovt > z - p_h)
+                return s * huge * huge; /* overflow */
+        }
+    } else if ((j & 0x7fffffff) >= 0x4090cc00) {        /* z <= -1075 */
+        if (((j - 0xc090cc00) | i) != 0)        /* z < -1075 */
+            return s * tiny * tiny;     /* underflow */
+        else {
+            if (p_l <= z - p_h)
+                return s * tiny * tiny; /* underflow */
+        }
+    }
     /*
      * compute 2**(p_h+p_l)
      */
-	i = j&0x7fffffff;
-	k = (i>>20)-0x3ff;
-	n = 0;
-	if(i>0x3fe00000) {		/* if |z| > 0.5, set n = [z+0.5] */
-	    n = j+(0x00100000>>(k+1));
-	    k = ((n&0x7fffffff)>>20)-0x3ff;	/* new k for n */
-	    t = zero;
-	    SET_HIGH_WORD(t,n&~(0x000fffff>>k));
-	    n = ((n&0x000fffff)|0x00100000)>>(20-k);
-	    if(j<0) n = -n;
-	    p_h -= t;
-	}
-	t = p_l+p_h;
-	SET_LOW_WORD(t,0);
-	u = t*lg2_h;
-	v = (p_l-(t-p_h))*lg2+t*lg2_l;
-	z = u+v;
-	w = v-(z-u);
-	t  = z*z;
-	t1  = z - t*(P1+t*(P2+t*(P3+t*(P4+t*P5))));
-	r  = (z*t1)/(t1-two)-(w+z*w);
-	z  = one-(r-z);
-	GET_HIGH_WORD(j,z);
-	j += (n<<20);
-	if((j>>20)<=0) z = SDL_NAME(scalbn)(z,n);	/* subnormal output */
-	else SET_HIGH_WORD(z,j);
-	return s*z;
+    i = j & 0x7fffffff;
+    k = (i >> 20) - 0x3ff;
+    n = 0;
+    if (i > 0x3fe00000) {       /* if |z| > 0.5, set n = [z+0.5] */
+        n = j + (0x00100000 >> (k + 1));
+        k = ((n & 0x7fffffff) >> 20) - 0x3ff;   /* new k for n */
+        t = zero;
+        SET_HIGH_WORD(t, n & ~(0x000fffff >> k));
+        n = ((n & 0x000fffff) | 0x00100000) >> (20 - k);
+        if (j < 0)
+            n = -n;
+        p_h -= t;
+    }
+    t = p_l + p_h;
+    SET_LOW_WORD(t, 0);
+    u = t * lg2_h;
+    v = (p_l - (t - p_h)) * lg2 + t * lg2_l;
+    z = u + v;
+    w = v - (z - u);
+    t = z * z;
+    t1 = z - t * (P1 + t * (P2 + t * (P3 + t * (P4 + t * P5))));
+    r = (z * t1) / (t1 - two) - (w + z * w);
+    z = one - (r - z);
+    GET_HIGH_WORD(j, z);
+    j += (n << 20);
+    if ((j >> 20) <= 0)
+        z = SDL_NAME(scalbn) (z, n);    /* subnormal output */
+    else
+        SET_HIGH_WORD(z, j);
+    return s * z;
 }
+
+/* vi: set ts=4 sw=4 expandtab: */