How to write a Program to perform Fibonacci series (8051)

ORG 0H
MOV R0,#30H
MOV @R0,#00H
MOV R1,#31H
MOV @R1,#01H
MOV R2,#09H
MOV A,#01H
BACK:ADD A,@R0
INC R0
INC R1
MOV @R1,A
DJNZ R2,BACK
HERE:SJMP HERE
MOV @R0,#00H
END