softfloat/s_countLeadingZeros64.c

   1
   2 #include <stdint.h>
   3 #include "primitives.h"
   4 #include "platform.h"
   5
   6 int softfloat_countLeadingZeros64( uint64_t a )
   7 {
   8     int count;
   9     uint32_t a32;
  10
  11     count = 32;
  12     a32 = a;
  13     if ( UINT64_C( 0x100000000 ) <= a ) {
  14         count = 0;
  15         a32 = a>>32;
  16     }
  17     /*------------------------------------------------------------------------
  18     | From here, result is current count + count leading zeros of `a32'.
  19     *------------------------------------------------------------------------*/
  20     if ( a32 < 0x10000 ) {
  21         count += 16;
  22         a32 <<= 16;
  23     }
  24     if ( a32 < 0x1000000 ) {
  25         count += 8;
  26         a32 <<= 8;
  27     }
  28     count += softfloat_countLeadingZeros8[ a32>>24 ];
  29     return count;
  30
  31 }
  32