[fusl] clang-format fusl

fusl/src/math/pow.c

 /* origin: FreeBSD /usr/src/lib/msun/src/e_pow.c */
 /*
  * ====================================================
  * Copyright (C) 2004 by Sun Microsystems, Inc. All rights reserved.
  *
  * Permission to use, copy, modify, and distribute this
  * software is freely granted, provided that this notice
  * is preserved.
  * ====================================================
  */
@@ skipping 13 matching lines @@
  *      2.  1 ** (anything)  is 1
  *      3.  (anything except 1) ** NAN is NAN
  *      4.  NAN ** (anything except 0) is NAN
  *      5.  +-(|x| > 1) **  +INF is +INF
  *      6.  +-(|x| > 1) **  -INF is +0
  *      7.  +-(|x| < 1) **  +INF is +0
  *      8.  +-(|x| < 1) **  -INF is +INF
  *      9.  -1          ** +-INF is 1
  *      10. +0 ** (+anything except 0, NAN)               is +0
  *      11. -0 ** (+anything except 0, NAN, odd integer)  is +0
- *      12. +0 ** (-anything except 0, NAN)               is +INF, raise divbyzero
- *      13. -0 ** (-anything except 0, NAN, odd integer)  is +INF, raise divbyzero
+ *      12. +0 ** (-anything except 0, NAN)               is +INF, raise
+ * divbyzero
+ *      13. -0 ** (-anything except 0, NAN, odd integer)  is +INF, raise
+ * divbyzero
  *      14. -0 ** (+odd integer) is -0
  *      15. -0 ** (-odd integer) is -INF, raise divbyzero
  *      16. +INF ** (+anything except 0,NAN) is +INF
  *      17. +INF ** (-anything except 0,NAN) is +0
  *      18. -INF ** (+odd integer) is -INF
- *      19. -INF ** (anything) = -0 ** (-anything), (anything except odd integer)
+ *      19. -INF ** (anything) = -0 ** (-anything), (anything except odd
+ * integer)
  *      20. (anything) ** 1 is (anything)
  *      21. (anything) ** -1 is 1/(anything)
  *      22. (-anything) ** (integer) is (-1)**(integer)*(+anything**integer)
  *      23. (-anything except 0 and inf) ** (non-integer) is NAN
  *
  * Accuracy:
  *      pow(x,y) returns x**y nearly rounded. In particular
  *                      pow(integer,integer)
  *      always returns the correct integer provided it is
  *      representable.
  *
  * Constants :
  * The hexadecimal values are the intended ones for the following
  * constants. The decimal values may be used, provided that the
  * compiler will convert from decimal to binary accurately enough
  * to produce the hexadecimal values shown.
  */
 
 #include "libm.h"
 
-static const double
-bp[]   = {1.0, 1.5,},
-dp_h[] = { 0.0, 5.84962487220764160156e-01,}, /* 0x3FE2B803, 0x40000000 */
-dp_l[] = { 0.0, 1.35003920212974897128e-08,}, /* 0x3E4CFDEB, 0x43CFD006 */
-two53  =  9007199254740992.0, /* 0x43400000, 0x00000000 */
-huge   =  1.0e300,
-tiny   =  1.0e-300,
-/* 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-017, /* -(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*/
-
-double pow(double x, double y)
-{
-        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;
-        uint32_t lx,ly;
-
-        EXTRACT_WORDS(hx, lx, x);
-        EXTRACT_WORDS(hy, ly, y);
-        ix = hx & 0x7fffffff;
-        iy = hy & 0x7fffffff;
-
-        /* x**0 = 1, even if x is NaN */
-        if ((iy|ly) == 0)
-                return 1.0;
-        /* 1**y = 1, even if y is NaN */
-        if (hx == 0x3ff00000 && lx == 0)
-                return 1.0;
-        /* NaN if either arg is NaN */
-        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;
-        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 ((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)  /* (-1)**+-inf is 1 */
-                                return 1.0;
-                        else if (ix >= 0x3ff00000) /* (|x|>1)**+-inf = inf,0 */
-                                return hy >= 0 ? y : 0.0;
-                        else                       /* (|x|<1)**+-inf = 0,inf */
-                                return hy >= 0 ? 0.0 : -y;
-                }
-                if (iy == 0x3ff00000) {    /* y is +-1 */
-                        if (hy >= 0)
-                                return x;
-                        y = 1/x;
-#if FLT_EVAL_METHOD!=0
-                        {
-                                union {double f; uint64_t i;} u = {y};
-                                uint64_t i = u.i & -1ULL/2;
-                                if (i>>52 == 0 && (i&(i-1)))
-                                        FORCE_EVAL((float)y);
-                        }
+static const double bp[] =
+    {
+        1.0, 1.5,
+},
+                    dp_h[] =
+                        {
+                            0.0, 5.84962487220764160156e-01,
+}, /* 0x3FE2B803, 0x40000000 */
+    dp_l[] =
+        {
+            0.0, 1.35003920212974897128e-08,
+},                              /* 0x3E4CFDEB, 0x43CFD006 */
+    two53 = 9007199254740992.0, /* 0x43400000, 0x00000000 */
+    huge = 1.0e300,
+                    tiny = 1.0e-300,
+                    /* 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-017,    /* -(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*/
+
+double pow(double x, double y) {
+  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;
+  uint32_t lx, ly;
+
+  EXTRACT_WORDS(hx, lx, x);
+  EXTRACT_WORDS(hy, ly, y);
+  ix = hx & 0x7fffffff;
+  iy = hy & 0x7fffffff;
+
+  /* x**0 = 1, even if x is NaN */
+  if ((iy | ly) == 0)
+    return 1.0;
+  /* 1**y = 1, even if y is NaN */
+  if (hx == 0x3ff00000 && lx == 0)
+    return 1.0;
+  /* NaN if either arg is NaN */
+  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;
+  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 ((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) /* (-1)**+-inf is 1 */
+        return 1.0;
+      else if (ix >= 0x3ff00000) /* (|x|>1)**+-inf = inf,0 */
+        return hy >= 0 ? y : 0.0;
+      else /* (|x|<1)**+-inf = 0,inf */
+        return hy >= 0 ? 0.0 : -y;
+    }
+    if (iy == 0x3ff00000) { /* y is +-1 */
+      if (hy >= 0)
+        return x;
+      y = 1 / x;
+#if FLT_EVAL_METHOD != 0
+      {
+        union {
+          double f;
+          uint64_t i;
+        } u = {y};
+        uint64_t i = u.i & -1ULL / 2;
+        if (i >> 52 == 0 && (i & (i - 1)))
+          FORCE_EVAL((float)y);
+      }
 #endif
-                        return y;
-                }
-                if (hy == 0x40000000)    /* y is 2 */
-                        return x*x;
-                if (hy == 0x3fe00000) {  /* y is 0.5 */
-                        if (hx >= 0)     /* x >= +0 */
-                                return sqrt(x);
-                }
-        }
-
-        ax = fabs(x);
-        /* special value of x */
-        if (lx == 0) {
-                if (ix == 0x7ff00000 || ix == 0 || ix == 0x3ff00000) { /* x is +-0,+-inf,+-1 */
-                        z = ax;
-                        if (hy < 0)   /* z = (1/|x|) */
-                                z = 1.0/z;
-                        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;
-                }
-        }
-
-        s = 1.0; /* sign of result */
-        if (hx < 0) {
-                if (yisint == 0) /* (x<0)**(non-int) is NaN */
-                        return (x-x)/(x-x);
-                if (yisint == 1) /* (x<0)**(odd int) */
-                        s = -1.0;
-        }
-
-        /* |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 ? s*huge*huge : s*tiny*tiny;
-                if (ix > 0x3ff00000)
-                        return hy > 0 ? s*huge*huge : s*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 = ax - 1.0;       /* 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 ss,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)      /* |x|<sqrt(3/2) */
-                        k = 0;
-                else if (j < 0xBB67A)  /* |x|<sqrt(3)   */
-                        k = 1;
-                else {
-                        k = 0;
-                        n += 1;
-                        ix -= 0x00100000;
-                }
-                SET_HIGH_WORD(ax, ix);
-
-                /* compute ss = 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 = 1.0/(ax+bp[k]);
-                ss = u*v;
-                s_h = ss;
-                SET_LOW_WORD(s_h, 0);
-                /* t_h=ax+bp[k] High */
-                t_h = 0.0;
-                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 = ss*ss;
-                r = s2*s2*(L1+s2*(L2+s2*(L3+s2*(L4+s2*(L5+s2*L6)))));
-                r += s_l*(s_h+ss);
-                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 = ss*(1+...) */
-                u = s_h*t_h;
-                v = s_l*t_h + t_l*ss;
-                /* 2/(3log2)*(ss+...) */
-                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) = (ss+..)*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);
-        }
-
-        /* 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 */
-                if (p_l + ovt > z - p_h)
-                        return s*huge*huge;         /* overflow */
-        } else if ((j&0x7fffffff) >= 0x4090cc00) {  /* z <= -1075 */  // FIXME: instead of abs(j) use unsigned j
-                if (((j-0xc090cc00)|i) != 0)        /* z < -1075 */
-                        return s*tiny*tiny;         /* underflow */
-                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 = 0.0;
-                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)/(t1-2.0) - (w + z*w);
-        z = 1.0 - (r-z);
-        GET_HIGH_WORD(j, z);
-        j += n<<20;
-        if ((j>>20) <= 0)  /* subnormal output */
-                z = scalbn(z,n);
-        else
-                SET_HIGH_WORD(z, j);
-        return s*z;
+      return y;
+    }
+    if (hy == 0x40000000) /* y is 2 */
+      return x * x;
+    if (hy == 0x3fe00000) { /* y is 0.5 */
+      if (hx >= 0)          /* x >= +0 */
+        return sqrt(x);
+    }
+  }
+
+  ax = fabs(x);
+  /* special value of x */
+  if (lx == 0) {
+    if (ix == 0x7ff00000 || ix == 0 ||
+        ix == 0x3ff00000) { /* x is +-0,+-inf,+-1 */
+      z = ax;
+      if (hy < 0) /* z = (1/|x|) */
+        z = 1.0 / z;
+      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;
+    }
+  }
+
+  s = 1.0; /* sign of result */
+  if (hx < 0) {
+    if (yisint == 0) /* (x<0)**(non-int) is NaN */
+      return (x - x) / (x - x);
+    if (yisint == 1) /* (x<0)**(odd int) */
+      s = -1.0;
+  }
+
+  /* |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 ? s * huge * huge : s * tiny * tiny;
+    if (ix > 0x3ff00000)
+      return hy > 0 ? s * huge * huge : s * 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 = ax - 1.0; /* 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 ss, 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)    /* |x|<sqrt(3/2) */
+      k = 0;
+    else if (j < 0xBB67A) /* |x|<sqrt(3)   */
+      k = 1;
+    else {
+      k = 0;
+      n += 1;
+      ix -= 0x00100000;
+    }
+    SET_HIGH_WORD(ax, ix);
+
+    /* compute ss = 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 = 1.0 / (ax + bp[k]);
+    ss = u * v;
+    s_h = ss;
+    SET_LOW_WORD(s_h, 0);
+    /* t_h=ax+bp[k] High */
+    t_h = 0.0;
+    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 = ss * ss;
+    r = s2 * s2 *
+        (L1 + s2 * (L2 + s2 * (L3 + s2 * (L4 + s2 * (L5 + s2 * L6)))));
+    r += s_l * (s_h + ss);
+    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 = ss*(1+...) */
+    u = s_h * t_h;
+    v = s_l * t_h + t_l * ss;
+    /* 2/(3log2)*(ss+...) */
+    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) = (ss+..)*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);
+  }
+
+  /* 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 */
+    if (p_l + ovt > z - p_h)
+      return s * huge * huge; /* overflow */
+  } else if ((j & 0x7fffffff) >= 0x4090cc00) {
+    /* z <= -1075 */                 // FIXME: instead of abs(j) use unsigned j
+    if (((j - 0xc090cc00) | i) != 0) /* z < -1075 */
+      return s * tiny * tiny;        /* underflow */
+    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 = 0.0;
+    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 - 2.0) - (w + z * w);
+  z = 1.0 - (r - z);
+  GET_HIGH_WORD(j, z);
+  j += n << 20;
+  if ((j >> 20) <= 0) /* subnormal output */
+    z = scalbn(z, n);
+  else
+    SET_HIGH_WORD(z, j);
+  return s * z;
 }