unsigned char x;
unsigned char xdata *p;  // Pointer to a byte in XDATA

p = 0x0000; 
x = *p;     // Gets the byte from address 0x0000 in XDATA

p = 0x1234;
x = *p;     // Gets the byte from address 0x1234 in XDATA

p = 0xFFFF;
x = *p;     // Gets the byte from address 0xFFFF in XDATA