bit operators

[filox]

not sure is it a c++ or a c question, but since i'm using c++, i'll ask
here...
i would like to use bit operators (&, |, <<), but on the type double,
because it has 64 bits. unfortunately, it seems i can't do that. can i
somehow define my own type that has the desired number of bits (i.e. using
bit fields) and then use those operators on that type?

 

[Adrian]

not sure is it a c++ or a c question, but since i'm using c++, i'll ask
here...
i would like to use bit operators (&, |, <<), but on the type double,
because it has 64 bits. unfortunately, it seems i can't do that. can i
somehow define my own type that has the desired number of bits (i.e. using
bit fields) and then use those operators on that type?

How about using the stl bitset?

#include <iostream>
#include <bitset>

int main(char *argv[], int argc)
{
std::bitset<64> b;

b[34]=true;
b[3]=true;

std::cout << b << std::endl;

b>>=5;
std::cout << b << std::endl;

b=255;
std::cout << b << std::endl;

b&=24;
std::cout << b << std::endl;

return 0;
}


Adrian

 

[Gianni Mariani]

not sure is it a c++ or a c question, but since i'm using c++, i'll ask
here...
i would like to use bit operators (&, |, <<), but on the type double,
because it has 64 bits. unfortunately, it seems i can't do that. can i
somehow define my own type that has the desired number of bits (i.e. using
bit fields) and then use those operators on that type?

If all you need is 64 bits, most modern compiler have a built in type.

i.e.

typedef unsigned long long bits_64;

If you need more you can define your own type e.g.

struct bits128
{
bits_64 m_lo;
bits_64 m_hi;
};

bits128 Bits( bits_64 lo, bits_64 hi )
{
bits128 retval = { lo, hi };
return retval;
}

bits128 operator|( const & bits128 lhs, const & bits128 rhs )
{
bits128 retval = { lhs.lo | rhs.lo, lhs.hi, rhs.hi };
}

.... plus a whole bunch more like this for all the other operators you need.

 

[filox]

thanks to everyone who replied!