Much ado about nothing!?!

Even more RE as I wade through the code for the Garu Zakato (big exploding bomb) and the Sheonites (spinning pyramids) that precede it.

The Garu Zakato explodes with 16 radial bullets
and 4 Brag Spario that target the Solvalou

I can't quite believe the amount of code - some 409 lines assembling to 610 bytes - devoted to two objects that have absolutely no bearing on the game whatsoever! Incidentally, the 68K code is almost exactly half that, some 200 lines.

For those not intimately familiar with Xevious, there are two Sheonites that appear to mirror each other perfectly. They decend from the top of the screen, 'dock' with the Solvalou for a handful of seconds, and the join together before shooting off the top of the screen again. They are indestructible, and serve no purpose whatsoever other than be something to look at.

One of the Sheonites appears to be implemented correctly,
the other, not so much...

It would be perfectly reasonable to assume that they are both handled by the one routine. But it's a strange mix; two independent routines that share a lot of (duplicated) code, but are oddly asymmetrical. And one of them is explicitly destroyed; the other left to be cleaned up after leaving the screen. I've yet to debug the transcoded routines completely, but it has left me scratching my head.

When I first implemented one of the Sheonites, it stubbornly refused to appear at all. Eventually I discovered that the object handler wasn't being called, and that was because a few objects were inadvertently skipped when the handlers were scheduled. In the process of looking for the bug, I decided I didn't quite like the way I'd written the round-robin scheduler, and in the process of cleaning it up and optimising it, I found the bug. Two birds with one stone...

I think I will tackle the Andor Genesis (mothership) next after debugging the other Sheonite. Part of that code comprises the last remaining section of the SUB CPU program to transcode. Nothing tricky at all, just lots of hard-coded references to object attributes.