MTile32x32 [ShapeNumber.w,]Xpos.w,Ypos.w ; Block-blit 32x32 shape to bitmap, size must be 32x32, align x/y

Performs a highly optimised blit of the currently-used or specified chunky Shape
into the currently used chunky Bitmap at Xpos,Ypos. The Shape should be 32x32 in
size and *both* Xpos and Ypos should be multiples of 32.