FUNCTION PCHI(M,X)
C WAHRSCHEINLICHKEIT FUER CHI(M)=X
C M : FREIHEITSGRADE - NACH DECUS NO. FOCAL 8-308
C FORTRAN II
	DF=FLOAT(M)
	BX=X
	A=0.5*X
	E=FLOAT(2*(M/2)-M)
	IF(E)1220,1227,1220
1220	IF(DF-2.)1230,1230,1227
1227	IF(BX-40.)1229,1230,1230
1229	YY=EXP(-A)
1230	IF(E)1240,1239,1239
1239	S=YY
	GOTO 1260
1240	X=-SQRT(X)
S	JMS UP0
	IF(X)1245,1245,1244
1244	P=(Z+1.)*0.5
	GOTO 1250
1245	P=(1.-Z)*0.5
1250	S=2.*P
1260	IF(DF-2.)1270,1270,1310
1270	PCHI=S
	RETURN
1310	X=0.5*(DF-1.)
	IF(E)1320,1319,1319
1319	Z=1.
	GOTO 1330
1320	Z=0.5
1330	IF(BX-40.)1380,1331,1331
1331	IF(E)1340,1332,1332
1332	E=0.
	GOTO 1350
1340	E=0.572365
1350	C=ALOG(A)
1360	IF(X-Z)1370,1369,1369
1369	E=E+ALOG(Z)
C TEST OB ABS(ARGUMENT) >= 20
	ARG=C*Z-A-E
	IF(ABS(ARG)-20.)1372,1372,1371
1371	ARG=20.*(ARG/ABS(ARG))
1372	S=S+EXP(ARG)
	Z=Z+1.
	GOTO 1360
1370	GOTO 1270
1380	IF(E)1385,1384,1384
1384	E=1.
	GOTO 1387
1385	E=0.56419/SQRT(A)
1387	C=0.
1390	IF(X-Z)1395,1394,1394
1394	E=E*A/Z
	C=C+E
	Z=Z+1.
	GOTO 1390
1395	S=S+C*YY
	GOTO 1270
SUP0,	0
	IF(X)1011,1020,1011
1011	CONTINUE
S	JMS UP1
S	JMP I UP0
1020	Z=0.
S	JMP I UP0
SUP1,	0
	Y=ABS(X)*0.5
	IF(Y-3.)1130,1119,1119
1119	Z=1.
S	JMP I UP1
1130	IF(Y-1.)1140,1139,1139
1139	CONTINUE
S	JMS UP2
S	JMP I UP1
1140	W=Y*Y
	Z=((.124819E-3*W-.10752E-2)*W+.519877E-2)*W
	Z=(((Z-.191983E-1)*W+.590540E-1)*W-.151969)*W
	Z=(((Z+.3191153)*W-.531923)*W+.797885)*Y*2.
S	JMP I UP1
SUP2,	0
	Y=Y-2.
	Z=((-.4526E-4*Y+.152529E-3)*Y-.195381E-4)*Y
	Z=(((-.676905E-3)*Y+.139006E-2)*Y-.79462E-3)*Y
	Z=(((Z-.203425E-2)*Y+.654979E-2)*Y-.105576E-1)*Y
	Z=(((Z+.116308E-1)*Y-.927945E-2)*Y+.535358E-2)*Y
	Z=((Z-.214127E-2)*Y+.53531E-3)*Y+.999937
S	JMP I UP2
	END