how to declare a xbyte address in the function's parameter?

I has defined some xbyte macro,as belows:

#define PA XBYTE[0XF100]
#define PB XBYTE[0XF200].....

now,i want pass the PA and PB as a parameter of a
function, how to declare them in the function?

if i wrote the function like this :

f(XBYTE * b)
{
 unsigned char temp;
 *b = temp;
}

call like this:

f(PA);

the keil's compile will be error.
--------------------------------------------
And if i wrote the function like belows :

f(unsigned char   b)
{
 uchar temp;
 b = temp;
}

call also like this:

f(PA);

keil's compile will passed,but the mcu will
not access the extran data RAM, and the RD/WR signal
will not pull low.

HOW CAN I declare a xbyte address in the function's parameter? THANK YOU.