#define h_inc() { head == FIFO_SIZE-1 ? head = 0 : head++; if (head == tail) head = -1, tail = 0;}
#define h_dec() { head == 0 ? head = FIFO_SIZE-1 : head--; if (head == tail) tail = -1;}
#define t_inc() { tail == FIFO_SIZE-1 ? tail = 0 : tail++; if (tail == head) tail = -1;}
#define h_inc() { head == FIFO_SIZE-1 ? head = 0 : head++; if (head == tail) head = -1, tail = 0;}
#define h_dec() { head == 0 ? head = FIFO_SIZE-1 : head--; if (head == tail) tail = -1;}
#define t_inc() { tail == FIFO_SIZE-1 ? tail = 0 : tail++; if (tail == head) tail = -1;}