}
DEFUN ("logb", Flogb, Slogb, 1, 1, 0,
- "Returns the integer that is the base 2 log of ARG.\n\
+ "Returns the integer not greater than the base 2 log of the magnitude of ARG.\n\
This is the same as the exponent of a float.")
(arg)
Lisp_Object arg;
{
- /* System V apparently doesn't have a `logb' function. It might be
- better to use it on systems that have it, but Ultrix (at least)
- doesn't declare it properly in <math.h>; does anyone really care? */
- return Flog (arg, make_number (2));
+#ifdef USG
+ error ("SYSV apparently doesn't have a logb function; what to do?");
+#else
+ Lisp_Object val;
+ double f = extract_float (num);
+
+ IN_FLOAT (val = logb (f), num);
+ XSET (val, Lisp_Int, val);
+ return val;
+#endif
}
/* the rounding functions */