// rho computation with floats for homework, by Frank Ruskey.
// Method 1 uses "uint64_t" from stdint; could also use "unsigned long long".
// Method 2 uses a union from idea of Riley Mottus.

#include<stdint.h>
#include<stdio.h>

typedef union {
   double d;
   struct {
      uint64_t mant : 52;
      uint16_t expo : 11;
      uint16_t sign :  1;
   } parts;
} dull;

int main( int argc, char *argv[] ){
  uint64_t x, p, two20=1ULL<<20;
  for (x=two20+1; x<=two20+32; ++x) {
  
     // Method 1
     double f64 = (double)(x & -x);
     p = ( *(( (uint64_t *) &f64 )) >> 52 ) - 1023ULL;
     
     // Method 2
     dull y;
     y.d = (double)(x & -x);
     
     printf( "rho(%llu) = %llu %d\n", x, p, y.parts.expo-1023 );
  }
  return(0);
}

/*
Frank@Frank-PC ~
$ gcc RhoTest.c

Frank@Frank-PC ~
$ ./a.exe
rho(1048577) = 0 0
rho(1048578) = 1 1
rho(1048579) = 0 0
rho(1048580) = 2 2
rho(1048581) = 0 0
rho(1048582) = 1 1
rho(1048583) = 0 0
rho(1048584) = 3 3
rho(1048585) = 0 0
rho(1048586) = 1 1
rho(1048587) = 0 0
rho(1048588) = 2 2
rho(1048589) = 0 0
rho(1048590) = 1 1
rho(1048591) = 0 0
rho(1048592) = 4 4
rho(1048593) = 0 0
rho(1048594) = 1 1
rho(1048595) = 0 0
rho(1048596) = 2 2
rho(1048597) = 0 0
rho(1048598) = 1 1
rho(1048599) = 0 0
rho(1048600) = 3 3
rho(1048601) = 0 0
rho(1048602) = 1 1
rho(1048603) = 0 0
rho(1048604) = 2 2
rho(1048605) = 0 0
rho(1048606) = 1 1
rho(1048607) = 0 0
rho(1048608) = 5 5
*/