In memory method of passing parameters to procedure

DATA SEGMENT
	A DB 22H
	B DB 33H
	C DW ?
DATA ENDS

CODE SEGMENT
	ASSUME CS:CODE,DS:DATA
	START:
		MOV AX,DATA
		MOV DS,AX
		
		CALL DO
		
		MOV AH,4CH
		INT 21H

		DO PROC NEAR
		MOV AL,A
		MOV BL,B
		ADD AL,BL
		MOV C,AX
		RET

CODE ENDS
END START