libm/s_isinf.c

   1 /*
   2  * Written by J.T. Conklin <jtc@netbsd.org>.
   3  * Changed to return -1 for -Inf by Ulrich Drepper <drepper@cygnus.com>.
   4  * Public domain.
   5  */
   6
   7 /*
   8  * isinf(x) returns 1 is x is inf, -1 if x is -inf, else 0;
   9  * no branching!
  10  */
  11
  12 #include "math.h"
  13 #include "math_private.h"
  14
  15 int __isinf(double x)
  16 {
  17         int32_t hx,lx;
  18         EXTRACT_WORDS(hx,lx,x);
  19         lx |= (hx & 0x7fffffff) ^ 0x7ff00000;
  20         lx |= -lx;
  21         return ~(lx >> 31) & (hx >> 30);
  22 }
  23 libm_hidden_def(__isinf)