text: #include<stdio.h>
  #include<stdint.h>
  
  typedef union {
  uint8_t REG;
  struct {
      unsigned P0 :1;
      unsigned P1 :1;
      unsigned P2 :1;
      unsigned P3 :1;
      unsigned P4 :1;
      unsigned P5 :1;
      unsigned P6 :1;
      unsigned P7 :1;
  } PIN;
  } Register;
  
  #define DDRB ((Register *)0x0001)
  
  int main() {
      DDRB->REG=0b00011000;
      DDRB->PIN.P0=1;
      printf("%X",DDRB->REG);
      return 0;
  }