1.3.4 多字节有符号数乘法.txt

来自「使用C51单片机进行二进制转换源码的算法介绍」· 文本 代码 · 共 52 行

SDOMUL:		
MOV	24H,R1				
MOV	A,R1
ADD		A,R2
DEC		A					
MOV	R1,A
MOV	A,@R1
ANL		A,#80H				
MOV	R6,A
JZ		NEG0				
NEG1:			
MOV	R1,24H				
MOV	22H,R2
ACALL	NEGTUN				
NEG0:			
MOV	28H,R0
MOV	A,R0
ADD		A,R3
DEC		A					
MOV	R0,A
MOV	A,@R0
ANL		A,#80H
MOV	R7,A
JZ		DDOMUL				
MOV	R1,#28H				
MOV	22H,R3
ACALL	NEGTUN
DDOMUL:		
MOV	A,R6
XRL		A,R7
MOV	23H,A
MOV	R0,28H
MOV	R1,24H
ACALL	DOMUL				
JNB		1FH,RETURN
NEG2:			
MOV	R1,27H				
MOV	22H,R5
ACALL	NEGTUN
RETURN:		
RET							
NEGTUN:		
SETB	C					
LP:				
MOV	A,@R1
CPL		A
ADDC	A,#00H
MOV	@R1,A
INC		R1				
DJNZ	22H,LP
RET