math: raise flags in log2l.c on <= 0 arguments, and fix volatile

[musl] / src / math / log2l.c

diff --git a/src/math/log2l.c b/src/math/log2l.c
index 8ebce9c..76a7aac 100644 (file)
--- a/src/math/log2l.c
+++ b/src/math/log2l.c
@@ -50,11 +50,6 @@
  * 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"
@@ -113,7 +108,7 @@ static const long double S[4] = {
 
 long double log2l(long double x)
 {
-       volatile long double z;
+       long double z;
        long double y;
        int e;
 
@@ -123,8 +118,8 @@ long double log2l(long double x)
                return x;
        if (x <= 0.0) {
                if (x == 0.0)
-                       return -INFINITY;
-               return NAN;
+                       return -1/(x+0); /* -inf with divbyzero */
+               return 0/0.0f; /* nan with invalid */
        }
 
        /* separate mantissa from exponent */