Add incomplet long double math support to libmingwex.a

winsup/mingw/mingwex/math/hypotl.c

@@ -0,0 +1,58 @@
+#include <math.h>
+
+typedef union
+{
+  long double value;
+  struct
+  {
+    unsigned mantissa[2];
+    unsigned sign_exponent : 16;
+    unsigned empty : 16;
+  } parts;
+} ieee_long_double_shape_type;
+
+
+
+/* Get int from the exponent of a long double.  */
+static __inline__ void
+get_ld_exp (unsigned exp,long double d)
+{
+  ieee_long_double_shape_type u;
+  u.value = d;
+  exp = u.parts.sign_exponent;
+}
+
+/* Set exponent of a long double from an int.  */
+static __inline__ void
+set_ld_exp (long double d,unsigned exp)
+{
+  ieee_long_double_shape_type u;
+  u.value = d;
+  u.parts.sign_exponent = exp;
+  d = u.value;
+}
+
+long double
+hypotl (long double x, long double y)
+{
+  unsigned exx = 0U;
+  unsigned eyy = 0U;
+  unsigned  scale;
+  long double xx =fabsl(x);
+  long double yy =fabsl(y);
+  if (!isfinite(xx) || !isfinite(yy))
+    return  xx + yy; /* Return INF or NAN. */
+
+  /* Scale to avoid overflow.*/
+  get_ld_exp (exx, xx);
+  get_ld_exp (eyy, yy);	
+  scale = (exx > eyy ? exx : eyy);
+  if (scale == 0)
+    return 0.0L;		
+  set_ld_exp (xx, exx - scale);
+  set_ld_exp (yy, eyy - scale);	
+  xx = sqrtl(xx * xx  + yy * yy);
+  get_ld_exp (exx,xx);
+  set_ld_exp (xx, exx + scale);
+  return xx;
+}