KEIL C51的XBYTE关键字

XBYTE

The XBYTE macro allows you to access individual bytes in the external data

memory of the 8051. You may use this macro in your programs as follows:

rval = XBYTE [0x0002];

XBYTE [0x0002] = 57;

to read or write the contents of the byte in external data memory at address

0002h.