Blit Store Left screen,blitnr,x,y to x1,y1,shift :
	Blit Store Left allows you to define up to 96 different scrolling
	zones.  Each of these zones can be associated with a specific
	scrolling operation which is determined by the variable SHIFT.
	SCREEN defines the screen that you want to scroll.
	BLITNR holds the number of the zone and can range from 1 to 96.
	X,Y refer to the coordinates of the top left-hand corner of the
	area to be scrolled and X1,Y1 to the point diagonally opposite.
	The routine now automatically chops the X and X1 values so that
	they allways ly on a 16 bit boundary !
	Ex.: 198 will become 196 , 307 will become 304
	SHIFT, if this value is positive the zone will be shifted to
	the right.  Negative values indicate that the scrolling will
	be to the left.
	SHIFT values range form -15 to +15.

Multi Blit start To end :
	The Multi Blit command scrolls the screen using the settings
	you have specified with the Blit Store Left instruction.
	START and END refer to the zones you wish to scroll.
!!!	Allways be sure that the screens where you have defined 
	scrolling zones are OPEN when you use this command, if not
	a crash will be certain. 					!!!
	If you have defined only 1 zone you should type :
		Multi Blit 1 To 1
	So with this command you can scroll up to 96 zones in one go !
	Why is the Multi Blit command so much faster than the original
	Scroll command from AMOS ? :
		speed is gained on two points :
		A) the BLIITER is fed directly with precalculated values.
		B) I only use the A and D blitter channels, the Scroll
		   command uses the B,C and D channels.

Blit Int On start To end :
	This command adds a new interrupt server to the VBLANK server
	chain which will do the same thing as the Multi Blit command !
	So the Multi Blit command is now executed every Vbl and is
	running totally independent of your AMOS PROGRAM !
!!!	Allways be sure that the screens where you have defined 
	scrolling zones are OPEN when you use this command, if not
	a crash will be certain. 					!!!

	Advantages : 
		     Time is saved for your AMOS PROGRAMS.
		     You don't have to wait for the Vbl to synchronize
		     the Scrolling with your screen display.

	Disadvantages :
		     None. Hmm...

Blit Int Off :
	Turn off the 'BLITTER' interrupt.
	The interrupt is removed automatically if you do a default
	or if you leave AMOS.

Blit Speed blitnr,shift :
	With this command you can change the SHIFT (speed) value
	after you have defined a scrolling zone.
	Only use positive values, it determines itself if the defined
	scrolling zone is scrolling to the left or to the right !

Blit Erase blitnr :
	Erases and frees the memory used by a particular scrolling
	zone.
	If blitnr is negative, ALL blit definitions are erased from
	memory.
	All Blit definitions are automatically erased from memory
	if you do a 'default' or if you leave AMOS.


Blit Left screen,x,y To x1,y1,shift :
	Does the same thing as the Blit Store Left command except that
	the scroll will be immediately executed.
	This command is still much faster than the AMOS Scroll command !

Blit Clear X:
	This is a simple command for clearing any bitplane of a screen.
	If X is negative, all bitplanes of a screen will be erased.
	But if X is positive (0 excluded), then the X vaue refers to the
	bitplane that has to be cleared !
	An 8 colour screen has 3 bitplanes, 1 -> 3 !
	It is about 80 % faster than the Cls command !