What was the first multi-kernel game?

[supercat]

What was the first game on the 2600 to feature more than one display kernel? Both in the narrow sense, of changing what code is used for part of the screen, or in a broader sense of replacing everything. (not counting games which sometimes don't bother to show the screen at all, like Chess when it's "thinking"). The earliest example of the latter I can think of is Asteroids, with three kernels (the copyright message, the rocks, and the ships+shots). Were there any earlier ones, whether by Atari or someone else? Space Invaders isn't as dramatic, but it uses a different kernel for empty invader rows than for full ones (not sure why) but more notably replaces the score kernel with a UFO kernel when the UFO flies across the screen. It might also use a different kernel for showing lives remaining, but I don't know about that.

Edited October 30, 2006 by supercat

[SeaGtGruff]

What was the first game on the 2600 to feature more than one display kernel?

Does Combat count? Did it have more than one kernel (for the tanks, airplanes, etc.)? I know the Combat disassembly is pretty easy to find, but I've never looked at it, so I have no idea how it's put together.

 

MR

[Feralstorm]

Presumably almost any of the early games with score displays count, since it switches from an assymetrical playfield display for the score area to a mirrored/repeated playfield with players/missiles/whatnot for the main area.

[supercat]

Presumably almost any of the early games with score displays count, since it switches from an assymetrical playfield display for the score area to a mirrored/repeated playfield with players/missiles/whatnot for the main area.

 

I don't mean games with more than one subkernel for different parts of the screen; I mean games which sometimes use completely different code to display the same part of the screen or even the entire screen.

 

In Space Invaders, the score subkernel is skipped over when the UFO is on screen and the UFO is shown instead. In Asteroids, the power-on copyright message is a little kernel all by itself, and after that there are two kernels which are used on alternate frames.

 

Combat uses the same kernel all the time whether it's showing tanks, biplanes, or jets. Even the "bomber" uses the same kernel.