vendor/libm-0.1.4/src/math/ilogbf.rs

   1 const FP_ILOGBNAN: i32 = -1 - 0x7fffffff;
   2 const FP_ILOGB0: i32 = FP_ILOGBNAN;
   3
   4 pub fn ilogbf(x: f32) -> i32 {
   5     let mut i = x.to_bits();
   6     let e = ((i >> 23) & 0xff) as i32;
   7
   8     if e == 0 {
   9         i <<= 9;
  10         if i == 0 {
  11             force_eval!(0.0 / 0.0);
  12             return FP_ILOGB0;
  13         }
  14         /* subnormal x */
  15         let mut e = -0x7f;
  16         while (i >> 31) == 0 {
  17             e -= 1;
  18             i <<= 1;
  19         }
  20         e
  21     } else if e == 0xff {
  22         force_eval!(0.0 / 0.0);
  23         if (i << 9) != 0 {
  24             FP_ILOGBNAN
  25         } else {
  26             i32::max_value()
  27         }
  28     } else {
  29         e - 0x7f
  30     }
  31 }