NPTL is no longer an add-on!

[platform/upstream/glibc.git] / math / s_catanl.c

diff --git a/math/s_catanl.c b/math/s_catanl.c
index 57d2e59..dd01d16 100644 (file)
--- a/math/s_catanl.c
+++ b/math/s_catanl.c
@@ -1,5 +1,5 @@
 /* Return arc tangent of complex long double value.
-   Copyright (C) 1997-2013 Free Software Foundation, Inc.
+   Copyright (C) 1997-2014 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -20,7 +20,14 @@
 #include <complex.h>
 #include <math.h>
 #include <math_private.h>
+#include <float.h>
 
+/* To avoid spurious overflows, use this definition to treat IBM long
+   double as approximating an IEEE-style format.  */
+#if LDBL_MANT_DIG == 106
+# undef LDBL_EPSILON
+# define LDBL_EPSILON 0x1p-106L
+#endif
 
 __complex__ long double
 __catanl (__complex__ long double x)
@@ -29,7 +36,7 @@ __catanl (__complex__ long double x)
   int rcls = fpclassify (__real__ x);
   int icls = fpclassify (__imag__ x);
 
-  if (__builtin_expect (rcls <= FP_INFINITE || icls <= FP_INFINITE, 0))
+  if (__glibc_unlikely (rcls <= FP_INFINITE || icls <= FP_INFINITE))
     {
       if (rcls == FP_INFINITE)
        {
@@ -55,27 +62,93 @@ __catanl (__complex__ long double x)
          __imag__ res = __nanl ("");
        }
     }
-  else if (__builtin_expect (rcls == FP_ZERO && icls == FP_ZERO, 0))
+  else if (__glibc_unlikely (rcls == FP_ZERO && icls == FP_ZERO))
     {
       res = x;
     }
   else
     {
-      long double r2, num, den;
+      if (fabsl (__real__ x) >= 16.0L / LDBL_EPSILON
+         || fabsl (__imag__ x) >= 16.0L / LDBL_EPSILON)
+       {
+         __real__ res = __copysignl (M_PI_2l, __real__ x);
+         if (fabsl (__real__ x) <= 1.0L)
+           __imag__ res = 1.0L / __imag__ x;
+         else if (fabsl (__imag__ x) <= 1.0L)
+           __imag__ res = __imag__ x / __real__ x / __real__ x;
+         else
+           {
+             long double h = __ieee754_hypotl (__real__ x / 2.0L,
+                                               __imag__ x / 2.0L);
+             __imag__ res = __imag__ x / h / h / 4.0L;
+           }
+       }
+      else
+       {
+         long double den, absx, absy;
+
+         absx = fabsl (__real__ x);
+         absy = fabsl (__imag__ x);
+         if (absx < absy)
+           {
+             long double t = absx;
+             absx = absy;
+             absy = t;
+           }
+
+         if (absy < LDBL_EPSILON / 2.0L)
+           {
+             den = (1.0L - absx) * (1.0L + absx);
+             if (den == -0.0L)
+               den = 0.0L;
+           }
+         else if (absx >= 1.0L)
+           den = (1.0L - absx) * (1.0L + absx) - absy * absy;
+         else if (absx >= 0.75L || absy >= 0.5L)
+           den = -__x2y2m1l (absx, absy);
+         else
+           den = (1.0L - absx) * (1.0L + absx) - absy * absy;
+
+         __real__ res = 0.5L * __ieee754_atan2l (2.0L * __real__ x, den);
 
-      r2 = __real__ x * __real__ x;
+         if (fabsl (__imag__ x) == 1.0L
+             && fabsl (__real__ x) < LDBL_EPSILON * LDBL_EPSILON)
+           __imag__ res = (__copysignl (0.5L, __imag__ x)
+                           * (M_LN2l - __ieee754_logl (fabsl (__real__ x))));
+         else
+           {
+             long double r2 = 0.0L, num, f;
 
-      den = 1 - r2 - __imag__ x * __imag__ x;
+             if (fabsl (__real__ x) >= LDBL_EPSILON * LDBL_EPSILON)
+               r2 = __real__ x * __real__ x;
 
-      __real__ res = 0.5 * __ieee754_atan2l (2.0 * __real__ x, den);
+             num = __imag__ x + 1.0L;
+             num = r2 + num * num;
 
-      num = __imag__ x + 1.0;
-      num = r2 + num * num;
+             den = __imag__ x - 1.0L;
+             den = r2 + den * den;
 
-      den = __imag__ x - 1.0;
-      den = r2 + den * den;
+             f = num / den;
+             if (f < 0.5L)
+               __imag__ res = 0.25L * __ieee754_logl (f);
+             else
+               {
+                 num = 4.0L * __imag__ x;
+                 __imag__ res = 0.25L * __log1pl (num / den);
+               }
+           }
+       }
 
-      __imag__ res = 0.25 * __ieee754_logl (num / den);
+      if (fabsl (__real__ res) < LDBL_MIN)
+       {
+         volatile long double force_underflow = __real__ res * __real__ res;
+         (void) force_underflow;
+       }
+      if (fabsl (__imag__ res) < LDBL_MIN)
+       {
+         volatile long double force_underflow = __imag__ res * __imag__ res;
+         (void) force_underflow;
+       }
     }
 
   return res;