6.6递推.txt

来自「排序、查找和非线性算法的51汇编源码」· 文本 代码 · 共 90 行

N		DATA	30H					
NFACT	EQU		31H					
TST:	
MOV	N,#5							
LCALL	FACT0						
MOV	N,#8							
LCALL	FACT0						
MOV	N,#10						
LCALL	FACT0					
STOP:	
LJMP	STOP
FACT0:	
MOV	A,N					
LCALL	FACT				
LCALL	HBCD					
MOV	R0,#NFACT 				
MOV	A,R1
MOV	@R0,A
INC		R0
MOV	A,R2
MOV	@R0,A
INC		R0
MOV	A,R3
MOV	@R0,A
INC		R0
MOV	A,R4
MOV	@R0,A
RET
FACT:
MOV	R2,A						
MOV	A,#1						
MOV	R3,A						
MOV	R7,A						
CLR		A
MOV	R5,A
MOV	R6,A
FACT1:	
MOV	A,R3						
XRL		A,R2						
JNZ		FACT2
RET								
FACT2:	
INC		R3						
MOV	A,R7						
MOV	B,R3
MUL		AB
MOV	R7,A
MOV	A,B
XCH		A,R6
MOV	B,R3
MUL		AB
ADD		A,R6
MOV	R6,A
CLR		A
ADDC	A,B
XCH		A,R5
MOV	B,R3
MUL		AB
ADD		A,R5
MOV	R5,A
LJMP	FACT1					
HBCD:	
CLR		A						
CLR 	A          				
MOV 	R3,A 
MOV 	R4,A 
MOV 	R5,A 
MOV 	R2,#10H    				
HB3: 
MOV 	A,R7  					
RLC 	A 
MOV 	R7,A 
MOV 	A,R6 
RLC 	A 
MOV 	R6,A 
MOV 	A,R5 					
ADDC 	A,R5 
DA 		A						 
MOV 	R5,A 
MOV 	A,R4 
ADDC 	A,R4 
DA 		A 
MOV 	R4,A 
MOV 	A,R3 
ADDC 	A,R3 
MOV 	R3,A 					
DJNZ 	R2,HB3 					
RET 
END