.TITLE	MRC7..	CHARACTER PROCEDURES IN MACRO
;
	.IDENT	/MRC7../
;
	.PAGE
	.SBTTL	.	EXTRACT A CHARACTER FROM A STRING
;
R$MOVC::				;EXTRACT A CHARACTER FROM A STRING
;
;		ENTRY CONDITIONS
;	R1 ->	STRING ADDRESS
;
;		EXIT CONDITIONS
;	R0 =	CHARACTER IF STATUS EQUALS SUCCESS
;
;
	TST @R1			;ARE THERE ANY CHARACTERS IN THE STRING
	BLE	30$		;J IF NOT CHARS IN STRING
	TST -2(R1)		;IS STRING WRITE PROTECTED
	BLE	30$		;J IF PROTECTED
;
	SAVE R1,R2,R3		;PROTECT REGISTERS
	DEC @R1			;REDUCE STRING LENGTH BY ONE
	MOVB 2(R1),R0		;HOLD FIRST CHARACTER
	MOV (R1)+,R3		;HOLD NUMBER OF CHARS TO MOVE DOWN STRING
	BLE	20$		;JI F NO CHARS TO MOVE  (IE LAST CHAR)
	MOV R1,R2		;HOLD ADDRESS OF FIRST  CHARACTER
	INC R2			;HOLD ADDRESS OF SECOND CHARACTER
;
10$:	MOVB (R2)+,(R1)+	;MOVE A CHARACTER DOWN THE STRING
	SOB R3,10$		;LOOP TILL ALL CHARACTERS MOVED
;
20$:	SETSUCCESS		;INDICATE JOB DONE WITH SUCCESS
	UNSAVE	R1,R2,R3	;RESTORE REGISTERS
	RETURN			;EXIT TO CALLING PROGRAM
;
30$:	EXITERROR		;INDICATE JOB FAILED AND EXIT TO CALLING PROGRAM
;
;
;
;
;
	.END
;
;