2.5-18.1

math/w_exp2.c

@@ -0,0 +1,36 @@
+/*
+ * wrapper exp2(x)
+ */
+
+#include <float.h>
+#include <math.h>
+#include "math_private.h"
+
+static const double o_threshold= (double) DBL_MAX_EXP;
+static const double u_threshold= (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1);
+
+double
+__exp2 (double x)		/* wrapper exp2 */
+{
+#ifdef _IEEE_LIBM
+  return __ieee754_exp2 (x);
+#else
+  double z;
+  z = __ieee754_exp2 (x);
+  if (_LIB_VERSION != _IEEE_ && __finite (x))
+    {
+      if (x > o_threshold)
+	/* exp2 overflow */
+	return __kernel_standard (x, x, 44);
+      else if (x <= u_threshold)
+	/* exp2 underflow */
+	return __kernel_standard (x, x, 45);
+    }
+  return z;
+#endif
+}
+weak_alias (__exp2, exp2)
+#ifdef NO_LONG_DOUBLE
+strong_alias (__exp2, __exp2l)
+weak_alias (__exp2, exp2l)
+#endif