* In the tests over the interval exp(+-10000), the logarithms
* of the random arguments were uniformly distributed over
* [-10000, +10000].
- *
- * ERROR MESSAGES:
- *
- * log singularity: x = 0; returns -INFINITY
- * log domain: x < 0; returns NAN
*/
#include "libm.h"
long double log2l(long double x)
{
- volatile long double z;
- long double y;
+ long double y, z;
int e;
if (isnan(x))
return x;
if (x <= 0.0) {
if (x == 0.0)
- return -INFINITY;
- return NAN;
+ return -1/(x*x); /* -inf with divbyzero */
+ return 0/0.0f; /* nan with invalid */
}
/* separate mantissa from exponent */
z += e;
return z;
}
+#elif LDBL_MANT_DIG == 113 && LDBL_MAX_EXP == 16384
+// TODO: broken implementation to make things compile
+long double log2l(long double x)
+{
+ return log2(x);
+}
#endif