3.2.2双字节减法.txt

里面有好多的原码,大家都来下载.用asm编写的

DBCDB:
CLR 	F0				
MOV 	R0,#7
ACALL 	NEGP0			
JC  		BSBRT				
MOV 	A,R4				
ADD 	A,R7
DA  	A
MOV 	R4,A
MOV 	A,R3
ADDC 	A,R6
DA  	A
MOV 	R3,A
MOV 	A,R2
ADDC 	A,R5
DA  	A
MOV 	R2,A
JC  		BSBRT				
MOV  	R0,#4
SETB 	F0
NEGP0:
MOV 	R1,#3				
CLR  	C
NGLP1:
MOV 	A,#99H				
SUBB  	A,@R0
MOV   	@R0,A
DEC   	R0
DJNZ  	R1,NGLP1				
INC   	R0
INC   	R0
MOV  	R1,#3
SETB 	C					
NGLP2:
CLR 	A
ADDC 	A,@R0
DA   	A
MOV  	@R0,A
DEC  	R0
DJNZ 	R1,NGLP2
BSBRT:
RET