1  /*
       2   * Public domain.
       3   */
       4  
       5  #if defined(LIBM_SCCS) && !defined(lint)
       6  static char rcsid[] = "$NetBSD: $";
       7  #endif
       8  
       9  /*
      10   * isinfl(x) returns 1 if x is inf, -1 if x is -inf, else 0;
      11   * no branching!
      12   * slightly dodgy in relying on signed shift right copying sign bit
      13   */
      14  
      15  #include <math.h>
      16  #include <math_private.h>
      17  #include <math_ldbl_opt.h>
      18  
      19  int
      20  ___isinfl (long double x)
      21  {
      22    double xhi;
      23    int64_t hx, mask;
      24  
      25    xhi = ldbl_high (x);
      26    EXTRACT_WORDS64 (hx, xhi);
      27  
      28    mask = (hx & 0x7fffffffffffffffLL) ^ 0x7ff0000000000000LL;
      29    mask |= -mask;
      30    mask >>= 63;
      31    return ~mask & (hx >> 62);
      32  }
      33  hidden_ver (___isinfl, __isinfl)
      34  #if !IS_IN (libm)
      35  weak_alias (___isinfl, ____isinfl)
      36  long_double_symbol (libc, ___isinfl, isinfl);
      37  long_double_symbol (libc, ____isinfl, __isinfl);
      38  #endif