1  #include <math.h>
       2  #include <errno.h>
       3  #include <limits.h>
       4  #include <math_private.h>
       5  #include <fenv.h>
       6  
       7  #if _GL_HAS_BUILTIN_ILOGB
       8  long int
       9  M_DECL_FUNC (__llogb) (FLOAT x)
      10  {
      11    int r;
      12    /* Check for exceptional cases.  */
      13    if (! M_SUF(__builtin_test_dc_ilogb) (x, 0x7f))
      14      r = M_SUF (__builtin_ilogb) (x);
      15    else
      16      /* Fallback to the generic ilogb if x is NaN, Inf or subnormal.  */
      17      r = M_SUF (__ieee754_ilogb) (x);
      18    long int lr = r;
      19    if (__glibc_unlikely (r == FP_ILOGB0)
      20        || __glibc_unlikely (r == FP_ILOGBNAN)
      21        || __glibc_unlikely (r == INT_MAX))
      22      {
      23  #if LONG_MAX != INT_MAX
      24        if (r == FP_ILOGB0)
      25  	lr = FP_LLOGB0;
      26        else if (r == FP_ILOGBNAN)
      27  	lr = FP_LLOGBNAN;
      28        else
      29  	lr = LONG_MAX;
      30  #endif
      31        __set_errno (EDOM);
      32        __feraiseexcept (FE_INVALID);
      33      }
      34    return lr;
      35  }
      36  declare_mgen_alias (__llogb, llogb)
      37  #else
      38  #include <math/w_llogb_template.c>
      39  #endif