sysdeps/ieee754/dbl-64/s_isinf.c

   1 /*
   2  * Public domain.
   3  */
   4
   5 /*
   6  * isinf(x) returns 1 is x is inf, -1 if x is -inf, else 0;
   7  * no branching!
   8  */
   9
  10 #include <math.h>
  11 #include <math_private.h>
  12 #include <ldbl-classify-compat.h>
  13 #include <shlib-compat.h>
  14
  15 int
  16 __isinf (double x)
  17 {
  18   int64_t ix;
  19   EXTRACT_WORDS64 (ix,x);
  20   int64_t t = ix & UINT64_C (0x7fffffffffffffff);
  21   t ^= UINT64_C (0x7ff0000000000000);
  22   t |= -t;
  23   return ~(t >> 63) & (ix >> 62);
  24 }
  25 hidden_def (__isinf)
  26 weak_alias (__isinf, isinf)
  27 #ifdef NO_LONG_DOUBLE
  28 # if LDBL_CLASSIFY_COMPAT && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
  29 compat_symbol (libc, __isinf, __isinfl, GLIBC_2_0);
  30 # endif
  31 weak_alias (__isinf, isinfl)
  32 #endif