C	PROGRAM GETNGH.FT
C	----------------
C
C
C	##	SUBROUTINE GETNGH.FT
C
C
C
C	PETER LEMKIN
C	IMAGE PROCESSING UNIT, DCBD
C	NATIONAL CANCER INSTITUTE
C	NATIONAL INSTITUTES OF HEALTH
C	9000 ROCKVILLE PIKE
C	BETHESDA, MD. 20014
C
C	MAY 17, 1977
C	MAY 16, 1977
C
C
C
C	INTRODUCTION
C	------------
C	GETNGH.FT IS A SUBROUTINE TO FETCH A CLEAN COPY OF THE 
C	I1j NEIGHBORHOOD IN (MEM,IBYTE,IY,IX) BM.
C
C	IT COMPILES AS:
C	--------------
C
C	.COMP GETNGH.RL_BMCMN,DSKB:GETNGH.FT
C
C	[0] ENTRY
S	ENTRY GETNG
S	CPAGE 2
S GETNG,	BLOCK 2
C
C
C	[1] 9 PIXEL 3X3 NEIGHBORHOOD FETCH 
C	SAVE IX,IY
	IXSAV=IX
	IYSAV=IY
C
C
C	[1.1] FETCH POINTS ON LINE Y-1
S	CLA CMA
S	TAD \IYSAVE
S	DCA \IY
C
S	CLA CMA
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I13=IZ
C
	IX=IXSAVE
S	JMS F2D
	I12=IZ
C
S	CLA IAC
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I11=IZ
C
C
C	[1.2] FETCH POINTS ON LINE Y
	IY=IYSAV
S	CLA CMA /-1
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I14=IZ
C
	IX=IXSAVE
S	JMS F2D
	I18=IZ
C
S	CLA IAC /+1
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I10=IZ
C
C
C	[1.3] FETCH POINTS ON LINE Y+1
S	CLA IAC /+1
S	TAD \IYSAVE
S	DCA \IY
C
S	CLA CMA /-1
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I15=IZ
C
	IX=IXSAVE
S	JMS F2D
	I16=IZ
C
S	CLA IAC
S	TAD \IXSAVE
S	DCA \IX
S	JMS F2D
	I17=IZ
C
C	RESET IX,IY
	IX=IXSAV
	IY=IYSAV
C
S	RETRN GETNG
C
CC	**************************************************
C	*INTERNAL SUBROUTINE    F 2 D
C	*****************************************************
C
C	IZ<==FETCH2D(MEM,IBYTE,IX,IY)
C		WHERE: IX AND IY ARE CLIPPED BEFORE THE CALL
C		TO [0:255];
C
S	CPAGE 32
S F2D,	0 /ENTRY
C
C	CLIP X TO [0:255]
S	TAD \IX
S	JMS CLIP
S	DCA \IX
C
C	CLIP Y TO [0:255]
S	TAD \IY
S	JMS CLIP
S	DCA \IY
C
C
	CALL FETCH2D
S	JMP I F2D /RETURN
C
C
C
S CLIP, 0 /INTERNAL SUBR
S	SPA
S	CLA /CLIP TO 0 IF < 0
S	TAD (-D256
S	SMA
S	CLA IAC /NO, MAKE IT 255
S	TAD (D256
S	JMP I CLIP
C
	END