Subject: Re: [stella] behold, i am become shiva, destroyer of kernals! From: KirkIsrael@xxxxxxxxxxxxx Date: 12 Mar 2004 06:13:21 -0000 |
> >The code you suggested just freezes on 1. > > Yeh, that was the post I was saying to ignore - I misread the BMI operation which determines if that section of > code gets executed and thought it was only exceuted when the pterry counter is -1 (rather than vice versa). Ah, msgs came out of order, I thought you were talking about the score fix. > The use of the Y register there does seem to be extraneous and you could simplify the LSR/ASL sequence. Hmmm... oh, yeah, since I was just right shifting so much to lose the extraneous bits, divide by 32 then multiply by 8, I can just divide by 4, and AND out the 3 rightmost bits: lsr tax lsr lsr lsr lsr asl asl asl becomes lsr tax lsr and #%11111000 and works just the same. > But that really neither here nor there... > Well, it really looked like it was one problem that was manifesting itself in a couple places - They looked like some kind of offset calculation problem or indexing problem. > > But if it aint broke... > > It really looked to me like you were supposed to be initialising some variable to 0 and instead were initialising it to point to some memory location that just happened to be 0 (or even some other value) until your code started to overlap that spot and cause a problem. > > But I could be completely off base there. > > Anyway... > > >bad news: I musta been relying on something in the old memory clear, > >because now I have some extraneous crap under the main sprites in my > >title screen kernal. This shows up on 2600 (supercharger) but not > >Z26 or PCAE > > But I just grabbed the latest macro.h and dropped it in and now I see your problem. > > But it's not CLEAN_START, it's another code-size problem - If I remove the SEI and/or CLD from CLEAN_START the problem goes away. But, if they're replaced with NOP it comes back. > > It looks like either your draw loop is running too long ot you're getting junk pushed into GRP0/GRP1 (VDELPn problem)? ??????? Weirdness. What are we missing here? Any of the (other) 6507/TIA gods around have any thoughts? > > >other bad news: sometimes walls aren't going away when they > >should. I have a hypothesis that it's when the ball is at a > >steeper angle, but I do the wall removal math BEFORE updating > >the ball position, so I don't know what would be wrong with it. > > I just played around with it a bit and the only problem I saw was when the ball it the lower right corner block, it removed the upper left corner block. Ugh, that's a new one :-( > However your data structure for the right wall comes after the left wall so it can't just be a rounding type error (ie: Removing the next block below the correct one). So... Could it be testing the ball when it's already out of bounds? ?? it registers a Playfield/Missile hit, then checks the position... > No, wait there does seem to be a rounding problem where every once and a while it removes the block that one block away from where it should. > > I'll poke around... I appreciate it. Hmmm...the commented-on "fix" was painstakingly hand debugged *before* Paul Slocum's great new kernal in there...I had to make a few other adjustmens, maybe things have shifted, so the previous adjustments (esp where the ball was between two blocks) might not work...previously i debugged it by formatting the bricks in an every-other brick pattern, then sending the ball in at a flat trajectory, and trying different values of the ball vertical position. In some ways I'm more nervous about the other less explicable memory and/or timing glitches... Thanks! -- KirkIsrael@xxxxxxxxxxxxx http://kisrael.com "I want to do to you what the spring does to cherry trees." "I want to do to *you* what you do to chinese food." --tufts.general ---------------------------------------------------------------------------------------------- Archives (includes files) at http://www.biglist.com/lists/stella/archives/ Unsub & more at http://www.biglist.com/lists/stella/
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