
                        Frame Drawing Code
                        ==================

Frame drawing is done using a very simple "programming language". The
instruction set is as follows.

0000 0000       End of frame drawing code
001x xxxx       Set X Position to xxxxx
010x xxxx       Set Y Position to xxxxx
011x xxxx       Draw Horizontal line Right size xxxxx
100x xxxx       Draw Vertical line Down size xxxxx

The X and Y coordinates are converted by multiplying the x by 3, and the y
by 2.

Lines are drawn from (x,y) to (x+n,y) and every pixel on the way is set.
When complete the cursor is at (x+n,y). Vertical lines operate similarly.

The cursor is initially at (0,0) at the top left of the screen.

