struct Sample{
    unsigned char var_a: 4;
    unsigned char var_b: 1;
    unsigned char var_c: 2;
    unsigned char var_d: 1;


    unsigned char var_e;
};

unsigned short int var_1 = 0x0010;

struct Sample hoge;
sample.var_a = var_1 & 0x00f0;
/* {0000 0000 0001 0000} & {0000 0000 1111 0000} = {0000 0000 0001 0000} */

hoge.var_a = (var_1 & 0x00f0) >> 4;