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
