I use 89c52, and I want to make a pointer in the serial interrupt service routine, the pointer points to an array in which I want the serial data to be saved, but the serial doesn't work at all with the pointer, when I put normal variable it works but I need to put a pointer, how can I do this??

...R_serial () interrupt 4
{
	if(RI)
	{
		 serialR = SBUF;
		 RI=0;
		 *PtrRx = serialR;
		 ++PtrRx;
	} /* wait for receive data */
	else
		TI = 0;
}
...