	.TITLE	TNUL
/
/  7 MAR 72 - MOD BY P. HENDERSON
/
/TEST NULL FAILURE FAULT FUNCTION
/EXECUTION TIME:  14 (TRUE) OR 13 (FALSE)
/                 MICROSECONDS
/CALLING SEQUENCE:  TNUL(DUMMY)
/   DUMMY:  ANY DUMMY ARGUMENT
/           (NEVER REFERENCED)
/EXIT:  AC=777777 IF POT NULL FAILED
/       AC=000000 IF POT NULL DIDN'T FAIL
/
	LOGAC
/
	.GLOBL TNUL
/
TNUL	XX
	IOT3
	JMP .-1
	RFW	/READ FAULT WORD
	AND (100000
	SZA!CLA	/SKIP ON POT NULLED
	CMA	/POT NULL FAILURE
SET	DAC*	LOGICA
	LAC	(600000
	DAC*	.MODEA	/SET DATA MODE TO LOGICAL
	JMP* TNUL
IOT3=703003
RFW=705313
	.END
