/RECURSIVE ROUTINE TO CALCULATE FACTORIALS
/*****************************************

/CALLED WITH NUMBER IN ACCUMULATOR
/ANSWER IN ACCUMULATOR ON RETURN


*10				/STARTIN ADDRESS


START,	LDX K 0			/SET INDEX-REGISTER
	LDS K 250		/SET STACK-POINTER
	LDA A X NUMBER
	JSR X FACTOR
	STA A X ANSWER
STOP,	JMP E STOP


FACTOR,	CMP A K 1
	BHI CONTIN
	RTS
CONTIN,	PSHA
	DECA
	JSR X FACTOR
	TAB
	PULA
	JSR X MULT
	RTS


MULT,	CLC			/SIMPLE MULTIPLIER
	STA A X TEM
	LDA A K 10
	STA A X CTR
	CLRA

LOOP,	ROLB
	BCC SHIFT
	ADD A E TEM

SHIFT,	DEC E CTR
	BEQ END
	CLC
	ASLA
	BRA LOOP

END,	RTS

NUMBER,	0			/NUMBER WHOSE FACTORIAL IS WANTED
ANSWER,	0			/ANSWER IS PUT HERE
CTR,	0
TEM,	0

$$$$$$$$			/END OF PROGRAMME