C Shifting bits in a byte

swap_bits.c

char swap_bits( char byte, int one, int two )
{
    char tmp_1, tmp_2, swap;
    int hex_1 = pow(2, one);
    int hex_2 = pow(2, two);
    tmp_1 = byte & hex_1;
    tmp_1 = tmp_1 >> abs( one - two );
    tmp_2 = byte & hex_2;
    tmp_2 = tmp_2 << abs( one - two );
    if ( tmp_1 == 0 && tmp_2 != 0 )
    {
        byte = byte ^ hex_2;
    }
    if ( tmp_2 == 0 && tmp_1 != 0 )
    {
        byte = byte ^ hex_1;
    }
    swap = tmp_1 | tmp_2;
    byte = swap | byte;
    return byte;
}