1.4.4 多字节有符号数除法.txt

数值算法,C51单片机的汇编程序

SDODIV:	
MOV	21H,R0				
MOV	A, R0
ADD		A, R3
DEC		A					
MOV	R0, A
MOV	A,@R0
ANL		A, #80H				
MOV	R6, A
JZ		NEG1				
NEG0:		
MOV	R0,21H				
MOV	22H, R3
ACALL	NEGTUN
NEG1:		
MOV	24H,R1				
MOV	A, R1
ADD		A, R2
DEC		A					
MOV	R1, A
MOV	A,@R1
ANL		A, #80H				
MOV	R7, A
JZ		ZERO
MOV	R0,24H				
MOV	22H, R2
ACALL	NEGTUN
ZERO:		
MOV	A, 24H
ADD		A, R2
MOV	R0, A			
MOV	A, R3
CLR		C					
SUBB	A, R2
MOV	R2, A
JZ		DODIV				
LP:			
MOV	@R0,#00H				
INC		R0
DJNZ	R2, LP
DDODIV:	
MOV	A,R6					
XRL		A, R7
MOV	23H, A
MOV	R0, 21H
MOV	R1, 24H
ACALL	DODIV				
JNB		1FH, RETURN
NEG2:		
MOV	22H,R3				
ACALL	NEGTUN
MOV	R0, 21H
RETURN:	
RET							
NEGTUN:						
SETB	C					
LP:			
MOV	A,@R0
CPL		A					
ADDC	A, #00H
MOV	@R0, A
INC		R0					
DJNZ	22H, LP
RET