C	PROGRAM GETNXN.FT
C	------------------
C
C	*** SUBROUTINE GETNXN(I11,)
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
C
C	FEB 16, 1977
C	JAN 17, 1977
C	JAN 14, 1977
C
C	PURPOSE
C	-------
C	FETCH NXN NEIGHBORHOOD CENTERED AT (IX,IY) FROM (MEM,IBYTE)
C	OF DIMENSION (IZ). (NOTE: N MUST BE ODD).
C	I11 IS THE FIRST ELEMENT OF A ROW STORED ARRAY OF SIZE NXN
C	DIMENSION I11(1)..I1N(1),I21(1)..I2N(1),..INN(1)
C
C
C	[0] GET THE ARGS
S	DUMMY CC
S	CPAGE 2
S CC,	BLOCK 2 /ARG FETCHER
C
S	ENTRY GETNX
S	CPAGE 2
S GETNX,	BLOCK 2
C
C	GET LINEBUFFER NAME
S	TAD I GETNX
S	DCA CC
S	INC GETNX#
S	TAD I GETNX
S	DCA CC#
S	INC GETNX#
C
C	[1] INITIALIZATION
	N=IZ
S	TAD \IZ
S	CLL RAR /DIVIDE BY 2
S	DCA \N2
C
	JJX=IX
	JJY=IY
C
C	[2] FETCH NEIGHBORHOOD
	DO 100 JY=1,N
	IY=(JJY-N2)+(JY-1)
C	COMPUTE: 	IY=MAX(0,MIN(IY,255))
S	TAD \IY
S	SPA
S	CLA /<0, ===> 0
S	TAD (-D255
S	SMA
S	CLA / GEQ 255, ===> 255
S	TAD (D255
S	DCA \IY
C
C
	DO 100 JX=1,N
	IX=(JJX-N2)+(JX-1)
C	COMPUTE: 	IX=MAX(0,MIN(IX,255))
S	TAD \IX
S	SPA
S	CLA /<0, ===> 0
S	TAD (-D255
S	SMA
S	CLA / GEQ 255, ===> 255
S	TAD (D255
S	DCA \IX
C
C
C	GET THE DATA
	CALL GETI1
S	TAD \I18
S	DCA I CC /STORE IT
S	INC CC#
100	CONTINUE
C
C	RESTORE (IX,IY)
	IX=JJX
	IY=JJY
S	RETRN GETNX
C
	END
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