.TITLE	ALTOV
;
; COPYRIGHT (C) 1977
; DIGITAL EQUIPMENT CORPORATION, MAYNARD, MASS.
;
;
; MODIFICATIONS:
;
;	02A -- ALWAYS LINK ALTERED TCB TO LEFT OF NULL TASK TCB
;
;
	.IDENT	/02A/
	.PSECT

.BLK.=.
	.MCALL	TCBDF$		;DEFINE TCB OFFSETS
	TCBDF$

.=.BLK.+160
10$:				;

.=.BLK.+170
	CALL	PAT1		;PERFORM TESTS IN PROPER ORDER
	BCS	20$		;IF CS LINK TCB IN HERE
	NOP

.=.BLK.+206
	BR	10$		;
20$:				;

.=.BLK.
	.PSECT	$$PAT1
$$PAT1=.
PAT1:	TST	T.TCBL(R5)	;IS THIS THE NULL TASK?
	SEC			;ASSUME TST BRANCHES
	BEQ	10$		;IF EQ YES
	CMPB	T.DPRI(R5),$MPARS+4 ;NEW TASK LOWER PRIORITY?
10$:	RETURN			;

.=$$PAT1
	.END