bithint.c

#include <stdio.h>

static unsigned int flipb(unsigned int x)
{
       x = (((x & 0xaaaaaaaa) >> 1) | ((x & 0x55555555) << 1));
       x = (((x & 0xcccccccc) >> 2) | ((x & 0x33333333) << 2));
       x = (((x & 0xf0f0f0f0) >> 4) | ((x & 0x0f0f0f0f) << 4));
       x = (((x & 0xff00ff00) >> 8) | ((x & 0x00ff00ff) << 8));
       return((x >> 16) | (x << 16));
}

static unsigned int lrot(unsigned int x, int n)
{
    return  (x << n) | (x >> -n);
}


static unsigned int rrot(unsigned int x, int n)
{
    return  (x << -n) | (x >> n);
}


union bitset
{
    unsigned int val;
    struct
    {
        unsigned char b0: 1;
        unsigned char b1: 1;
        unsigned char b2: 1;
        unsigned char b3: 1;
        unsigned char b4: 1;
        unsigned char b5: 1;
        unsigned char b6: 1;
        unsigned char b7: 1;
    } m_field[sizeof(int)];
    unsigned char data[sizeof(int)];
};



int main()
{
//    int i =3;
//    i = FLIPBACK(i);
//    printf("%d", i);
    union bitset bs = {.val = 0xff};

    union bitset bs1 = {.val = 0xFF000003};

    bs1.val = flipb(bs1.val);


    bs.val = lrot(bs.val, 16);
    bs.val = rrot(bs.val, 3);

    ///printf("%d\r\n", bs.val);

    return 0;
}