1.4.1 双字节无符号数除法.txt

来自「《MCS-51单片机应用开发实用子程序》配套源代码」· 文本 代码 · 共 68 行

ORG		1000H
OVER	DATA	2FH
DUDIV:		
MOV	A,R7					
JNZ		START				
MOV	A,R6					
JZ		ERROR				
START:		
MOV	A,R5					
JNZ		START1				
MOV	A,R4					
JNZ		START1
RET							
START1:		
CLR		A					
MOV	R2,A			
MOV	R3,A
MOV	R1,#16				
DIV0:		
CLR		C					
MOV	A,R4
RLC		A
MOV	R4,A
MOV	A,R5
RLC		A					
MOV	R5,A
MOV	A,R2
RLC		A	
MOV	R2,A					
MOV	A,R3
RLC		A
MOV	R3,A
MOV	A,R2					
SUBB	A,R6
JC		NEXT				
INC		R4					
MOV	R3,A
MOV	A,R0
MOV	R2,A
NEXT:		
DJNZ	R1,DIV0				
MOV	A,R3					
JB		ACC.7,ROUND			
MOV	A,R2					
RLC		A
MOV	R2,A
MOV	A,R3
RLC		A
SUBB	A,R7					
JC		DONE
JNZ		ROUND
MOV	A,R2
SUBB	A,R6
JC		DONE				
ROUND:		
MOV	A,R4
ADD		A,#1H
MOV	R4,A
MOV	A,R5
ADDC	A,#0H
MOV	R5,A
DONE:		
MOV	OVER,#0H			
RET
ERROR:		
MOV	OVER,#0FFH			
RET