6.4.5表的分块查找.txt

这是《MCS-51单片机应用开发实用子程序》配套源代码,对初学者很有用的

IDLST	EQU	2000H			
N		EQU	6				
OBJH	DATA	30H			
OBJL	DATA	31H			
FIND	BIT		00H			
TEST:	
MOV	P2,#HIGH(IDLST)		
MOV	R0,#LOW(IDLST)
MOV	DPTR,#DATS
MOV	R2,#60H
LOOP:	
CLR		A
MOVC	A,@A+DPTR
MOVX	@R0,A
INC		R0
INC		DPTR
DJNZ	R2,LOOP
MOV	OBJH,#78H			
MOV	OBJL,#33H
LCALL	BLKSRCH				
MOV	OBJH,#2FH			
MOV	OBJL,#68H
LCALL	BLKSRCH				
STOP:	
LJMP	STOP				
BLKSRCH:
MOV	R2,#N				
MOV	DPTR,#IDLST			
IDSRCH:	
MOVX	A,@DPTR				
MOV	R4,A
INC		DPTR
MOVX	A,@DPTR
MOV	R5,A
INC		DPTR
MOVX	A,@DPTR				
MOV	R6,A
INC		DPTR
MOVX	A,@DPTR
INC		DPTR
CLR		C
SUBB	A,OBJL				
MOV	A,R6
SUBB	A,OBJH
JNC		IDSRCHE				
DJNZ	R2,IDSRCH			
CLR		FIND				
RET
IDSRCHE:
MOVX	A,@DPTR			
MOV	R6,A
INC		DPTR
MOVX	A,@DPTR
CLR		C
SUBB	A,R5					
MOV	R7,A
MOV	A,R6
SUBB	A,R4
RRC		A					
MOV	R6,A
MOV	A,R7
RRC		A
MOV	R7,A					
JZ		BLK0
INC		R6					
BLK0:	
MOV	DPH,R4				
MOV	DPL,R5
BLK1:	
MOVX	A,@DPTR				
INC		DPTR
MOV	R2,A
MOVX	A,@DPTR
INC		DPTR
XRL		A,OBJL				
JNZ		BLK2				
MOV	A,R2					
XRL		A,OBJH
JZ		BLK3				
BLK2:	
DJNZ	R7,BLK1				
DJNZ	R6,BLK1
CLR		FIND				
RET
BLK3:	
MOV	A,#0FEH				
ADD		A,DPL
MOV	DPL,A
JC		BLK4
DEC		DPH
BLK4:	
SETB	FIND				
RET