[stella] HELP Kernel timing

Subject: [stella] HELP Kernel timing
From: Dennis Debro <ddebro@xxxxxxxxxxxxx>
Date: Mon, 26 Aug 2002 16:33:41 -0400
I am having problems with my kernel and need some help.

My goal is to create a port of Climber5 that was written for the 400/800. I was using Piero Cavina's kernel because it would work perfectly for this game. The problems I've encoutered are I would like the players to be in single line resolution and I'd like to have ~4 frames of animation for my main player (GRP0). To do this I was going to have to modify the kernel slightly. The major updates would be to add indirect indexing for the main player. I also didn't want to pad the main player with zeroes as I thought that would be a waste of ROM space.

Anyway the problem I'm having is I'm spending too much time on the player positioning scanline (besides the fact that the player jumps a little horizontally). When I position the player I have to update GRP0 graphics too because it may be on that scanline. I'm using a jsr (I know it uses a lot or time) to update GRP0 but it's done after the critical code is done. This routine at worst would take about 29 cycles (excluding the jsr).

I'm including a snipplet of my kernel. It's using aspects from Piero's MultiSprite Demo (http://www.biglist.com/lists/stella/archives/199704/msg00015.html) and the skipDraw routine submitted by Thomas (thank you). If I need to send more let me know. In the kernel I'm supplying I'm not doing any PF graphics. In the final version I would need to include those too.

Please help me because I have hit a road block here.


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