.TITLE	CONCAT
	.IDENT	/X01.00/
;
;  Author:	Gilbert J. DeLeeuw
;  Date:	August 20, 1984
;  Name:	CONCAT - Concatenate strings
;  Function:	Concatenate two strings by appending string 2 to string 1
;
;
;  Parameters:
;
;	R0 - Size of string 1
;	R1 - Address of string 1
;
;	R2 - Size of string 2
;	R3 - Address of string 2
;
CONCAT::
	TST	R2			;Test length of string 2
	BLE	DONE			;If null string
;
; Save starting point
	MOV	R1,-(SP)		;Save starting address
;
; Point to first free byte
	ADD	R0,R1			;Point to end of first string
;
; Copy string 2
10$:	MOVB	(R3)+,(R1)+		;Copy character
	SOB	R2,10$			;Loop over length
;
; Get descriptor for new string
	MOV	R1,R0			;Copy ending address
	MOV	(SP)+,R1		;Restore starting address
	SUB	R1,R0			;Subtract to get length
;
; Done
DONE:	RTS	PC			;Return to caller
	.END