This is a list of some key points that should be remembered when
programming the blitter.

*  Write  bltsize  last; writing this register starts the blit.

*  Modulos and pointers are in bytes; width is in words and height is in
   pixels.  The least significant bit of all pointers and modulos is
   ignored.

*  The order of operations in the blitter is  masking ,  shifting , logical
   combination of sources,  area fill , and  zero flag  setting.

*  In ascending mode, the blitter increments the pointers, adds the
   modulos, and  shifts  to the right.

*  In  descending mode , the blitter decrements the pointers, subtracts
   the modulos, and shifts to the left.

*   area fill  only works correctly in  descending mode .

*  Check  bltdone  before writing blitter registers or using the results
   of a blit.

*   shifts  are done on immediate data as soon as it is loaded.


    ecs blitter .
   -------------
   For information relating to the blitter hardware in the Enhanced Chip
   Set, see  appendix c .


 example:  clearmem 
 example:  simpleline 
 example:  rotatebits