#include <stdio.h>
    main() {
      int           a, b;
      unsigned int  x, y;
      a = b = 0xaa55;  x = y = 0xaa55;
      printf("\n a=%4x  b=%4x  x=%4x  y=%4x",a,b,x,y);
        a = a << 1;  b = b >> 1;
        x = x << 1;  y = y >> 1;
        printf("\n a=%4x  b=%4x  x=%4x  y=%4x",a,b,x,y);
        printf("\n");
        while(1);
    }