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.