FDD1: 
MOV 	B,A 					
MOV 	R2,#0 				
MOV 	A,R7 
DEC 	A 
MOV 	R3,A 				
FD61: 
CLR 	C 				 
MOV 	A,R3 
SUBB 	A,R2 
JC 		FD69 				
RRC 	A 					
ADD 	A,R2 				
MOV 	R4,A 				
MOVC 	A,@A+DPTR			
CJNE 	A,B,FD65				
CLR 	OV 					
MOV 	A,R4 				
RET 
FD65: 
JC 		FD68 				
MOV 	A,R4 				
DEC 	A 				
MOV 	R3,A 				
SJMP 	FD61 				
FD68: 
MOV 	A,R4 				
INC 		A 				
MOV 	R2,A 				
SJMP 	FD61 				 
FD69: 
SETB 	OV	 				
RET