1.3.1 双字节无符号数乘法.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 41 行

ORG		2000H
DOMUL:						
MOV 	33H,#0
MOV 	32H,#0
MOV 	31H,#0
MOV 	30H,#0
START:			
MOV 	R0H,#30H				
MOV	A,@R0				
ADD		A,R4					
MOV 	@R0,A				
INC	 	R0				
MOV	A,@R0
ADDC	A,R5					
MOV 	@R0,A				
INC 		R0					
MOV	A,@R0
ADDC	A,#0
MOV 	@R0,A				
INC	 	R0				
MOV	A,@R0
ADDC	A,#0
MOV 	@R0,A				
CLR		C
CJNE	R7,#0,BB				
MOV	A,R6										
SUBB	A,#1
MOV	R6,A
JNZ		START				
SJMP	CC
BB:			
MOV	A,R6					
SUBB	A,#1
MOV	R6,A
MOV	A,R7
SUBB	A,#0
MOV	R7,A
JNC		START				
CC:			
RET