Interrupt driven Buffered Serial Input

[skimask]

@ DEVICE PIC16F628A , HS_OSC , WDT_OFF , PWRT_ON , MCLR_ON , BOD_ON , LVP_OFF , PROTECT_OFF
'HS 20mhz external, watchdog off, powerup timer on, mclr external, brown out detect on, low volt program off , code protect off

resetplaceholder: 'wordpad, arial black, size 8, reg, 1600x1200 screen, 16f628A code
DEFINE	OSC	20	'20mhz

serdata var byte : serialbuffer var byte[255] : bufferpointer var byte
bufferdata var byte : temp var byte

startupholder:	goto skipsubs	'skip over all the commonly used subroutines

ON INTERRUPT GOTO INTHANDLER
DISABLE INTERRUPT
INTHANDLER:	if pir1.5 = 1 then	'if serial data rx'd
			serdata = rcreg		'save serial port data right away
			pir1.5 = 0		'reset the RX flag
			if ( rcsta.1 = 1 ) or ( rcsta.2 = 1 ) then	'check for err, if frame/overrun error,
				rcsta.4 = 0 : rcsta.4 = 1 : serdata = rcreg : serdata = 0
			else
				if bufferpointer = 255 then goto intfinish	'buffer is full
				serialbuffer[bufferpointer] = serdata
 : bufferpointer = bufferpointer + 1	'save data in buffer, bump pointer
				goto INTHANDLER	're-check serial port just in case another character came in while saving data
                                                        '...not likely
			endif
		endif

intfinish:	RESUME
ENABLE INTERRUPT

getcharacterfrombuffer:
		if bufferpointer = 0 then return	'no data in buffer in the first place!
		buffereddata = serialbuffer[0]	'get oldest data from buffer
		for temp = 0 to 254 : serialbuffer[temp] = serialbuffer[temp+1] : next temp	'shift data down one byte
		serialbuffer[255]=0	'set last byte in buffer to zero since it's meaningless
		bufferpointer = bufferpointer - 1	'one less byte in buffer
		return

skipsubs:	option_reg=8 : pie1=32 : trisa=0 : porta=0 : trisb=$ef : portb=16 : t1con=0 : t2con=0
		cmcon=7 : ccp1con=0 : vrcon=0 : txsta=0 : rcsta=$90 : pir1.5=0 : spbrg=33 : intcon=$e0	'9600 baud
		for temp = 0 to 255 : serialbuffer[temp] = 0 : next temp

mainloop:	goto mainloop	'do it all over again

END

I modified one of my old programs. This works for me, always has.
I've left the character handling and the modifications of the program to you to make work for your PIC.