.TITLE	MR12.. STRING PROCEDURES IN MACRO
	.IDENT	/MR12../
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	.PAGE
	.SBTTL	.	STRING ADDITION ROUTINE
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;
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R$ADDTO::			;ADD ONE STRING TO ANOTHER
;
;			ENTRY CONDITIONS
;
;		R1 -> STRING (A)
;		R2 -> STRING (B)
;
;			EXIT CONDITIONS
;
;		STRING (B) IS APPENDED TO STRING (A)
;
	SAVE R0,R3,R4		;SAVE R0,R3 AND R4
;
	MOV (R2),R0		;HOLD COUNT OF NUMBER OF CHARS TO TRANSFER
	BLE	60$		;J IF NO CHARACTER TO COPY
	MOV R1,R3		;HOLD ADDRESS OF MASTER STRING
	ADD @R1,R3		;INDEX TO NEXT FREE SLOT
	CMPB (R3)+,(R3)+	;R3 -> TO FIRST FREE SLOT
;
	MOV R2,R4		;HOLD ADDRESS OF APPEND STRING
	CMPB (R4)+,(R4)+	;R4 -> TO FIRST CHARACTER
;
50$:	CMP -2(R1),@R1		;IS STRING FULL
	BLE	60$		;J IF STRING FULL OR WRITE PROTECTED
	MOVB (R4)+,(R3)+	;APPEND A CHARCATER AND INDEX TO NEXT CHAR
	INC @R1			;INDEX CHARACTER COUNT
	SOB R0,50$		;LOOP TILL EITHER APPEND SOURCE EXAUSTED
				;OR MASTER STRING FULL
;
60$:	UNSAVE R0,R3,R4		;RESTORE R0,R3 & R4
	RETURN			;EXIT TO CALLING ROUTINE
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	.END
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