SUBROUTINE WALL(WALCOL,WALROW,WALDIR)
	IMPLICIT INTEGER (A-Z)
#
#	THIS SUBROUTINE DECIDES WHICH DIRECTION TO
#	MOVE A MONSTER WHEN HE RUNS INTO A WALL.
#
	INCLUDE/NL SY:PACMAN.CMN
	DIMENSION PREF(4)
#
#	DETERMINE LEFT/RIGHT AND UP/DOWN PREFERENCES
#
	IF (COL > WALCOL) [		#PACMAN IS TO OUR RIGHT
	  X1 = RIGHT
	  X2 = LEFT
	  ]
	ELSE [				#PACMAN IS TO OUR LEFT
	  X1 = LEFT
	  X2 = RIGHT
	  ]
	IF (ROW > WALROW) [		#PACMAN IS BELOW US
	  Y1 = DOWN
	  Y2 = UP
	  ]
	ELSE [				#PACMAN IS ABOVE US
	  Y1 = UP
	  Y2 = DOWN
	  ]
#
#	GIVE PREFERENCE TO A NINETY DEGREE TURN.
#
	IF (WALDIR == LEFT .OR. WALDIR == RIGHT) [
	  PREF(1) = Y1
	  PREF(2) = Y2
	  PREF(3) = X1
	  PREF(4) = X2
	  ]
	ELSE [
	  PREF(1) = X1
	  PREF(2) = X2
	  PREF(3) = Y1
	  PREF(4) = Y2
	  ]
#
#	SELECT THE FIRST LEGAL DIRECTION IN OUR PREFERENCE ARRAY
#
	DO I = 1,4 [
	  WALDIR = PREF(I)
	  IF (TSTBIT(MSTATE(WALCOL,WALROW),WALDIR) == 1)
	    BREAK
	  ]
	RETURN
	END