6.7回溯.txt

MCS－51单片机应用开发实用子程序.zip

STACK	EQU		1FH					
BOTTOM	EQU		00H					
TOP		DATA	3EH					
OUT		EQU		20H					
IN		EQU		30H					
N		EQU		8					
M		EQU		30				
K		DATA	3FH					
TST:	
MOV	SP,#5FH						
LCALL	SETNULL						
MOV	DPH,#OUT					
MOV	DPL,#0
MOV	R2,#0
CLR		A
CLROUT:	
MOVX	@DPTR,A
INC		DPTR
DJNZ	R2,CLROUT
MOV	R0,#IN						
MOV	R2,#N+1
CLRIN:	
MOV	@R0,A
INC		R0
DJNZ	R2,CLRIN
MOV	K,#0							
MOV	A,#0							
LCALL	DPUSH
MOV	A,#M						
LCALL	DPUSH
LCALL	BEIBAO						
STOP:	LJMP	STOP
WLIST:	
DB		1,9,12						
DB		6,3,20
DB		15,5
BEIBAO:	
LCALL	DPOP						
MOV	R2,A							
LCALL	DPOP
MOV	R3,A							
MOV	DPTR,#WLIST
MOVC	A,@A+DPTR
MOV	R4,A							
CLR		C
SUBB	A,R2							
JNZ		BB1							
MOV	A,R3							
ADD		A,#IN
MOV	R0,A
MOV	A,R4
MOV	@R0,A
MOV	DPH,#OUT					
MOV	A,K							
MOV	B,#N
MUL		AB
MOV	DPL,A
MOV	R0,#IN						
MOV	A,R3
INC		A
MOV	R7,A							
SAVE:	
MOV	A,@R0						
JZ		SAVE1						
MOVX	@DPTR,A						
INC		DPTR
SAVE1:
INC		R0
DJNZ	R7,SAVE
INC		K							
BB1:
MOV	A,R3							
INC		A
XRL		A,#N
JZ		BBE							
JNC		BB2							
MOV	A,R2							
LCALL	DPUSH
MOV	A,R3							
LCALL	DPUSH
MOV	A,R3							
ADD		A,#IN
MOV	R0,A
MOV	A,R4
MOV	@R0,A
MOV	A,R3							
INC		A
LCALL	DPUSH
MOV	A,R2							
CLR		C
SUBB	A,R4
LCALL	DPUSH
LCALL	BEIBAO						
LCALL	DPOP						
MOV	R3,A
LCALL	DPOP
MOV	R2,A							
BB2:	
MOV	A,R3
ADD		A,#IN
MOV	R0,A
MOV	A,#0							
MOV	@R0,A
MOV	A,R3
INC		A							
LCALL	DPUSH
MOV	A,R2							
LCALL	DPUSH
LCALL	BEIBAO						
BBE:
RET									
SETNULL:
MOV	A,#BOTTOM					
MOV	TOP,A						
RET									
DPUSH:	
INC		TOP							
MOV	DPH,#STACK					
MOV	DPL,TOP						
MOVX	@DPTR,A						
RET									
DPOP:	
MOV	DPH,#STACK					
MOV	DPL,TOP						
MOVX	A,@DPTR						
DEC		TOP							
RET									
END