Imported Upstream version 4.8.1

[platform/upstream/gcc48.git] / libquadmath / math / jnq.c

diff --git a/libquadmath/math/jnq.c b/libquadmath/math/jnq.c
index d82947a..56a1836 100644 (file)
--- a/libquadmath/math/jnq.c
+++ b/libquadmath/math/jnq.c
@@ -11,9 +11,9 @@
 
 /* Modifications for 128-bit long double are
    Copyright (C) 2001 Stephen L. Moshier <moshier@na-net.ornl.gov>
-   and are incorporated herein by permission of the author.  The author 
+   and are incorporated herein by permission of the author.  The author
    reserves the right to distribute this material elsewhere under different
-   copying permissions.  These modifications are distributed here under 
+   copying permissions.  These modifications are distributed here under
    the following terms:
 
     This library is free software; you can redistribute it and/or
@@ -56,6 +56,7 @@
  *
  */
 
+#include <errno.h>
 #include "quadmath-imp.h"
 
 static const __float128
@@ -273,7 +274,16 @@ jnq (int n, __float128 x)
                    }
                }
            }
-         b = (t * j0q (x) / b);
+         /* j0() and j1() suffer enormous loss of precision at and
+          * near zero; however, we know that their zero points never
+          * coincide, so just choose the one further away from zero.
+          */
+         z = j0q (x);
+         w = j1q (x);
+         if (fabsq (z) >= fabsq (w))
+           b = (t * z / b);
+         else
+           b = (t * w / a);
        }
     }
   if (sgn == 1)
@@ -374,6 +384,9 @@ ynq (int n, __float128 x)
          a = temp;
        }
     }
+  /* If B is +-Inf, set up errno accordingly.  */
+  if (! finiteq (b))
+    errno = ERANGE;
   if (sign > 0)
     return b;
   else