/ 3	FORTRAN II EXTENDED SUBROUTINE & FUNCTION LIBRARY
/
/	FUNCTION TATN (X)
/
/	RESULT IN GRAD
/
/	23-SEP-78			W. HOUBEN
/
	LAP
	ENTRY	TATN
	DUMMY	ARGM
	OPDEF	TADI	1400
	OPDEF	JMPI	5400
	OPDEF	MQL	7421	/ MQ=AC ; AC=0
	OPDEF	MQA	7501	/ AC=AC.OR.MQ
	OPDEF	CAM	7621	/ AC=0 ; MQ=0
	OPDEF	SWP	7521	/ AC=MQ ; MQ=AC
	ABSYM	PNTR	10
/
/	ATAN(I)=TAN(I)*64.
/
C4000,
ATAN,	4000
	DECIM
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	4095	/ < LIMIT >
	OCTAL
/
TATN,	BLOCK	2	/ TATN - ENTRY
	TAD	TATN
	DCA	CDF1
CDF1,	HLT
	TADI	TATN#
	DCA	ARGM
	INC	TATN#
	TADI	TATN#
	DCA	ARGM#
	INC	TATN#
	CALL	0,FAD	/ FAC=ARGUMENT
ARGM,	BLOCK	2
	TAD	ACH
	SNA
	JMP	RETURN	/ ZERO=ZERO
	AND	C4000
	MQL		/ AND SAVE IT
	CLA CLL CMA RAR	/ AC=3777
	AND	ACH
	DCA	ACH	/ FAC=ABS(FAC)
	TAD	ACH
	AND	(3770
	TAD	(-2070
	SMA CLA		/ FAC > 64. ?
	JMP	SET90	/ YES:
	JMP	NEXT	/ GOTO NEXT PAGE
/
	PAGE
/
ATANX,	ATAN
NEXT,	TAD	ACH	/ FAC=FAC*64.
	TAD	(60
	DCA	ACH
	CALL	0,FIX	/ AC=IFIX(FAC)
	CIA		/ NEGATE AND
	DCA	SAVE	/ SAVE IT
/
	TAD	ATANX	/ TABLE ADDR
	DCA	PNTR
LOOP,
	TAD	SAVE
	TADI	PNTR
	SPA CLA
	JMP	LOOP
FOUND,	TAD	ATANX
	CIA
	TAD	PNTR
RTN,	CALL	0,FLOT
	TAD	ACH
	MQA		/ RESULT HAS ARG SIGN
	DCA	ACH
RETURN,	CLA CLL IAC RAL	/ FAST RETURN
	TAD	TATN
	DCA	CDF2
	TAD	TATN#
	DCA	SAVE
CDF2,	HLT
	JMPI	SAVE
SET90,	TAD	(D90
	JMP	RTN
SAVE,	0
	END