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