.TITLE	ABSGRD - ROUTINE TO CONVRT ABSOLUTE INT COORD TO GRID F.P. COORD

.IDENT	'ABSGRD'

.PSECT	ABSGRD

;	KEN DEMERS
;	UTRC
;	NOVEMBER 1979

;	THIS ROUTINE CONVERTS AN ABSOLUTE INTEGER
;	X,Y COORDINATE TO A FLOATING POINT SCALED
;	COORDINATE AS DETERMINED BY THE GRID COORDINATE
;	SYSTEM.
;			[ (XACOR-RIDGX )	   ]
;	XVALUE  =	[ (----------- )  * XRANGE ]  + XMIN
;			[ ( XABMAX     )	   ]

;	ON ENTRY:

;	R1 = A(ABSOLUTE X COORDINATE)
;	R2 = A(ABSOLUTE Y COORDINATE)

;	ASSIGNMENTS

AC0	= %0			;FPP ACCUMULATOR 0

;	INTERNAL GLOBALS

.GLOBL	A$BSGRD

;	EXTERNAL GLOBALS

.GLOBL X$ABMAX,Y$ABMAX,X$RANGE,Y$RANGE,X$MIN,Y$MIN
.GLOBL	R$IDGX,R$IDGY



A$BSGRD: SETF			;SET FPP INTO S.P. MODE
	SETI			;SET FPP INTO SHORT INTEGER MODE
	SUB	#R$IDGX,(R1)	;SUB R$IDGX FROM ABS COORD
	LDCIF	(R1),AC0	;GET ABSOLUTE INT X COORD
	DIVF	X$ABMAX,AC0	;DIVIDE BY X$ABMAX
	MULF	X$RANGE,AC0	;MULT * X$RANGE
	ADDF	X$MIN,AC0	;ADD X$MIN
	STF	AC0,(R1)	;STORE GRID SCALED F.P. X COORD
	SUB	#R$IDGY,(R2)	;SUB R$IDGY FROM ABS COORD
	LDCIF	(R2),AC0	;GET ABSOLUTE INT Y COORD
	DIVF	Y$ABMAX,AC0	;DIVIDE BY Y$ABMAX
	MULF	Y$RANGE,AC0	;MULT * Y$RANGE
	ADDF	Y$MIN,AC0	;ADD Y$MIN
	STF	AC0,(R2)	;STORE GRID SCALED F.P. Y COORD
	RETURN
	.END