sysdeps/ieee754/dbl-64/wordsize-64/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 #include <shlib-compat.h>
  15
  16 int
  17 __isinf (double x)
  18 {
  19         int64_t ix;
  20         EXTRACT_WORDS64(ix,x);
  21         int64_t t = ix & UINT64_C(0x7fffffffffffffff);
  22         t ^= UINT64_C(0x7ff0000000000000);
  23         t |= -t;
  24         return ~(t >> 63) & (ix >> 62);
  25 }
  26 hidden_def (__isinf)
  27 weak_alias (__isinf, isinf)
  28 #ifdef NO_LONG_DOUBLE
  29 # if defined LDBL_CLASSIFY_COMPAT && SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_23)
  30 compat_symbol (libc, __isinf, __isinfl, GLIBC_2_0);
  31 # endif
  32 weak_alias (__isinf, isinfl)
  33 #endif