Added support for blitter fill and single pixel line operations. Games generally do not require this, as most were written in pure 68000 (elite and frontier for example do all polygons in software). I guess this made the code more portable.
Demos do use the blitter to do polygon filling however, Odyssey by Alcatraz for instance. While testing the demo I realised I still had not put in the correct exception for divide by zero. That is now done too.
Next up, it is really, really time to take apart the display code and put it back together with support for HAM,EHB and dual playfield mode. Also adding in correct dma timings for data fetch and hopefully finally fixing up the problems with some screen definitions being completely wrong. Phew, a lot to do, still it is nice to have a goal.
I added save/load of hardware state today. This means i can let the emulation run for as long as needed, and then reload exactly that point in emulation.
I spent much of the day debugging the blitter. Basically there has been something wrong with line drawing since i got work bench working. Classic example of this, was the single pixel error on the boot up image. Well it turned out to be a problem with the shifter on the B channel of the blitter. This is used to provide textured line support. However the first write of the line would potentially be masked out because i was initialising the previous shifted out data to zero. It seems more sensible to copy the data on line start into the previous shift register and this fixes the problem.