本人在项目中用到了，实际测试OK

typedef struct//位操作
{
	unsigned char bit0 : 1;
	unsigned char bit1 : 1;
	unsigned char bit2 : 1;
	unsigned char bit3 : 1;
	unsigned char bit4 : 1;
	unsigned char bit5 : 1;
	unsigned char bit6 : 1;
	unsigned char bit7 : 1;	
}iar_bits;

DEFINE_SFR(iar_bits,iar1,0x02);
#define iar1_3 iar1.bit3
#define iar1_2 iar1.bit2
#define iar1_1 iar1.bit1
#define iar1_0 iar1.bit0

unsigned short eepromread(unsigned char addr)
{
		_emi = 0;
	unsigned short backup;
	_eea = addr;
	_mp1l = 0x40;
	backup = _mp1h;//这个有些单片机可能会不一样，可能是_bp
	_mp1h = 1;
	iar1_1 = 1;
	iar1_0 = 1;
	while(iar1_0);
	_iar1 = 0;	
	_mp1h = backup;
	_emi = 1;
	return _eed;	
}

void eepromwrite(unsigned char eeaddr,unsigned short eedata)
{	_emi = 0;
	unsigned short backup;
	_eed = eedata;
	_eea = eeaddr;
	_mp1l = 0x40;
	backup = _mp1h;
	_mp1h = 1;

	iar1_3 = 1;
	iar1_2 = 1;

	while(iar1_2);
	_iar1 = 0;
	_mp1h = backup;	
		_emi = 1;
	_mp1h=0;
	_mp1l=0;	
}