1 files changed, 71 insertions, 0 deletions
diff --git a/winsup/cygwin/math/nextafterl.c b/winsup/cygwin/math/nextafterl.c
new file mode 100644
index 000000000..5db3af74a
--- /dev/null
+++ b/winsup/cygwin/math/nextafterl.c
@@ -0,0 +1,71 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+/*
+   nextafterl.c
+   Contributed by Danny Smith <dannysmith@users.sourceforge.net>
+   No copyright claimed, absolutely no warranties.
+
+   2005-05-09
+*/
+
+#include <math.h>
+
+long double
+nextafterl (long double x, long double y)
+{
+  union {
+      long double ld;
+      struct {
+        /* packed attribute is unnecessary on x86/x64 for these three variables */
+        unsigned long long mantissa;
+        unsigned short expn;
+        unsigned short pad;
+      } parts; 
+  } u;
+
+  /* The normal bit is explicit for long doubles, unlike
+     float and double.  */
+  static const unsigned long long normal_bit = 0x8000000000000000ull;
+  u.ld = 0.0L;
+  if (isnan (y) || isnan (x))
+    return x + y;
+
+  if (x == y )
+     /* nextafter (0.0, -O.0) should return -0.0.  */
+     return y;
+
+  u.ld = x;
+  if (x == 0.0L)
+    {
+      u.parts.mantissa = 1ull;
+      return y > 0.0L ? u.ld : -u.ld;
+    }
+
+  if (((x > 0.0L) ^ (y > x)) == 0)
+    {
+      u.parts.mantissa++;
+      if ((u.parts.mantissa & ~normal_bit) == 0ull)
+	u.parts.expn++;
+    }
+  else
+    {
+      if ((u.parts.mantissa & ~normal_bit) == 0ull)
+	u.parts.expn--;
+      u.parts.mantissa--;
+    }
+
+  /* If we have updated the expn of a normal number,
+     or moved from denormal to normal, [re]set the normal bit.  */ 
+  if (u.parts.expn & 0x7fff)
+    u.parts.mantissa |=  normal_bit;
+
+  return u.ld;
+}
+
+/* nexttowardl is the same function with a different name.  */
+long double
+nexttowardl (long double, long double) __attribute__ ((alias("nextafterl")));
+