File ALOG.RA

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/
/
/	A  L  O  G
/	-  -  -  -
/
/SUBROUTINE	ALOG(X)
/
/ VERSION 5A 4-26-77 (MH)
/
	SECT	ALOG
	JA	#ALOG
	0			/WORKING SPACE FOR EXPONENT DIDDLE.
	0
	0
ALOGTM,	0
	0
	0
	0
F2ALOG,	F 2.
FPI2,	1
	3110
	3755
/
	EXTERN	#ARGER
ALOG0,	TRAP4	#ARGER
	JA	ALGRTN		/RETURN NOW.
/
	EXTERN	#ARGER
ALOGM1,	TRAP4	#ARGER
	JA	ALGRTN
	TEXT	+ALOG  +
ALOGXR,
BPALOG,	F 0.0
XRALOG,	F 0.0
ALOG1,	F 0.0
ALOG2,	F 0.0
F1ALOG,	F 1.
/
ALOGMG,	0
	0
	13			/CORRECT EXPONENT DIDDLER.
/
/
/
/
ALOGL1,	0
	3777
	7742
/
ALOGE2,	0
	2613
	4414
/
	ORG	10*3+BPALOG
	FNOP
	JA	ALOGXR
	0
ALGRTN,	JA	.
ALOGL2,	7777
	4000
	4100
/
ALOGL3,	7777
	2517
	0310
/
ALOGL4,	7776
	4113
	7211
/
ALOGL5,	7776
	2535
	3301
/
ALOGL6,	7775
	4746
	0771
/
ALOGL7,	7774
	2236
	4304
/
ALOGL8,	7771
	4544
	1735
	BASE	0
#ALOG,	STARTD
	FLDA	10*3
	FSTA	ALGRTN
	FLDA	0
	SETX	XRALOG
	SETB	BPALOG
	BASE	BPALOG
	LDX	1,1	
	FSTA	BPALOG
	FLDA%	BPALOG,1  /ADDR OF X
	FSTA	BPALOG
	STARTF
	FLDA%	BPALOG	/GET X
	JEQ	ALOG0	/IF  =0 THEN ERROR
	JLT	ALOGM1	/IF<0 THEN ERROR
	LDX	-1,0	/IF >0 THEN START DOING
	FSTA	ALOG1		/SAVE IN A TEMP.
	FSUB	F1ALOG		/KNOCK OFF ONE.
	JEQ	ALGRTN		/IF ZERO EXIT. LOG(1)=0
	JGE	ALOGST		/IF POSITIVE LOG>0
	FLDA	F1ALOG		/NEGITE. INVERT IT.
	FDIV	ALOG1		/BY DIVIDING INTO ONE.
	FSTA	ALOG1
	LDX	0,0		/RESET SIGN TO NEGATIVE.
	JA	.+3		/AVOID USELESS LOAD INSTRUCTION.
/
ALOGST,	FLDA	ALO0



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