I am sorry to disappoint you after your hard work, but the rom (and therefore tios.h) have line drawing routines. I don't know about circles though. The rom's line drawing commands are: MoveTo and LineTo. MoveTo moves the current point (you don't see it, it just moves it), and LineTo draws a line from the current point to a specified point, and it also changes the current point to the specified point (I think).