GAME OVER - for 2022 at least!

In the process of transcoding all the enemy AI logic, I ended up finishing off a few other housekeeping routines as the logic was embedded in them. Those routines comprised transition of one Solvalou to the next, and ending the game. Not quite 100% there as there's still no high score entry, but close now.

Game Over!

I also implemented the Solvalou being hit, exploding and ending the turn. A few bugs in the transcode made harder work of it than I'd hoped - including one I had to sleep on - but done and dusted now.

I also discovered that I haven't implemented the tile flip for 2x2 tile sprites completely. As the Solvalou explodes, the same sprites are displayed for a handful of frames and they are periodically flipped based on an asynchronous timer. I haven't tackled this just yet; I'll have to consider the best approach. I may even leave it until I work on optimising the Neo Geo code, as anything further I do now may end up getting re-written anyway.

I had actually looked at the destruction of the flying enemies first, but there was a snag I hadn't expected. It's just a technical detail concerning the difference in implementation between the Z80 and 68K. I just have to work out the optimal solution. Not a big deal, but finishing off the Solvalou seemed more straightforward. A moot point now as I have little option but to tackle it next.

EDIT: I forgot the Bacura! 😳

At a bit over 5,500 lines in the MAIN program, the 2:1 ratio of Z80 to 68K instructions is almost exactly right; I'm really getting down to the last few functions to be transcoded now. Annoying that I've pretty much run out of time to work on it this year, but sometimes you just have to take holidays. 😜

UPDATE: I managed to squeeze a bit more time on the transcode; some more housekeeping so that the high score is updated on-the-fly, and bonus Solvalou awarded according to dipswitch settings.

Bonus Solvalou at 20K and updated High Score

In the process I decided to byte-reverse the storage of all the scores in the game. It made the bonus calculations easier, without affecting the efficiency of any of the other routines.

Finally, I fixed a bug that has been in the transcode and eluding me for weeks now if not longer. It involves the score occasionally appearing as a solid black line, and after implementing high score update, it started occurring at the same time for the high score as well - so doubly annoying! A theory came to me out of the blue tonight - it turned out to be completely wrong, but by then I was determined to find the issue.

It was between the core and the Neo Geo layers; in the core's score display code (a BCD print routine) I was sending the tile code as a byte but the Neo Geo code was assuming the upper byte of the word was zero... which it was... most of the time... until it wasn't. So nice to have finally fixed it!

UPDATE: found a few free minutes to do the Bacura. I had to add support for double-height (only) sprites.

Bacura - the forgotten foe!