.TITLE INDEX
; MODIFIED INDEX FUNCTION FOR ANALYTICALC
;COPYRIGHT(C) 1984 G. EVERHART
;
INDEX::
	.WORD	^M<R1,R2,R3,R4,R5,R6,R7>
; FIRST SEARCH FOR NULL CHARACTER IN INPUT STRING, THEN LOOK FOR
;MATCH UP TO THAT POINT.
	CLRL	R7
	MOVL	#256.,R5
	MOVL	4(AP),R6	;R6 IS STRING ADDRESS
	LOCC	R7,R5,(R6)	;LOCATE 0 (IN MAX 256 CHARS)
	BNEQ	1$		;IF NE WE FOUND A 0 SOMEWHERE
3$:	MOVL	R5,R0		;ELSE RETURN 256. AS RESULT.
	RET
1$:	MOVZBL	@8(AP),R7	;R7 GETS CHAR
; SUPPOSE WE SAID MAX 6 CHARS AND HAD
; A B C <0> D E (<0> = NULL)
; 1 2 3  4  5 6
; 1ST LOCC GIVES 3 CHARS LEFT
; 6-3=3 BUT WE WANT TO ENSURE THAT IF STRING IS NOT FOUND WE
; RETURN 4.
	SUBL3	R0,R5,R5	;R5 GETS 256 - NO. BYTES THAT WERE LEFT
				;THUS R5 IS STRING LENGTH NULL TERMINATED.
	INCL	R5		;BUMP UP BY 1 AGAIN
; IF WE SEARCH FOR B ABOVE, LOCC GIVES R0=3, R5 HAS 4
	LOCC	R7,R5,(R6)	;SO RE HUNT FOR STRING
	BEQL	3$		;IF NOT THERE, RETURN LENGTH
	SUBL3	R0,R5,R0	;IF IT IS THERE,SUBTRACT LENGTH LEFT TO
			;GET STRING LOCATION.
	INCL	R0		;THEN ADD 1 TO ACCOUNT FOR FORTRAN SUBSCRIPTS
	RET
	.END