Embedded Systems: An Integrated Approach by Pearson

326 EMBEDDED SYSTEMS

Logical

Table 9.3a | Logical Operators

Data OR AND EX-OR INVERT

X,Y X|Y X&Y X^Y ~X, ~Y

Shift

Table 9.3b | Shift Operators

A data may be left or right shifted, a fi xed number of times.

The notation for left shift is << and for right shift, it is >>

The way to use is as shown

i) 0x34>>3 shifts the data right three times.

ii) 0x7E<<4 shifts the data 4 times to the left.

Example 9.13

#include <AT89X51.H>

unsigned char W, X, Y, Z;

void main(void)

{

X = 0x45;

Y = 0x78;

Z = 0x67;

W = 0xAB;

P1 = X&Y; //AND operation

P2 = X|Y; //OR operation

P3 = Z<<3; //Left shift

P0 = W>>2; //Right shift

}

9.1.2 | Serial Communication

Frequently ...