#include <stdio.h>
#include <stdlib.h>

union instructionSet {
    struct Brane{
        unsigned int opcode: 4;
        unsigned int address: 12;
    } brane;
    struct Cmp{
        unsigned int opcode: 4;
        unsigned int blank: 1;
        unsigned int rsvd: 3;
        unsigned char letter: 8;
    } cmp;
    struct {
        unsigned int rsvd: 16;
    } reserved;
};

int main() {

    union instructionSet IR;// = (union instructionSet*)calloc(1, 2);

    printf("size of union %ld\n", sizeof(union instructionSet));
    printf("size of reserved %ld\n", sizeof(IR.reserved));
    printf("size of brane %ld\n", sizeof(IR.brane));
    printf("size of brane %ld\n", sizeof(IR.cmp));


    return 0;
}