>>BTW, I saw that Asteroids is an 8K cart, which rather surprises me since I
>>think it's not THAT complicated... so I'm only curious if all ROM revisions
>>have 8K or if there are some with less (4K, for instance...). And I still
>>wonder what they needeed all that ROM space for...
>
>Someone explained how the Asteroids kernel worked a while back and it's a
>pretty complicated flicker routine!! Also, as has been stated, in order to
>save processing time, tables and code redundancy can be used. So it's
That was me, I think. In a nutshell, there's two separate kernels: the
asteroids are all drawn on the same frame, then all the other objects are
drawn on the next frame. That also means all the collision checking has
to be done in software, taking some more space.
>possible that Asteroids "unrolls" a lot of its loops and uses lookup tables
>in the extra space.
>
>It's probably true, though, that it had plenty of space left over for the
>copyright message.
Looking at the binaries, that it does. Actually, about 2k of the space in
the non-copyright version is just unused, and about 500 bytes of that is
used in the copyright version. Both versions also have 2 full pages of
lookup tables that look simple enough to calculate in code instead.
>The copyright/title-screen is something they tended to add to their games
>around that time, like Yars' Revenge. It also might have been a reaction
>to Activision which always reserved a portion of the screen to their
>copyright. I was wondering whether Activision ever had to sacrifice some
>'game' for that logo... Seems very wasteful on their 2K titles to have it
>there, even if it's not the rainbow one.
Hmm, possibly. Stampede is a 2k game, and there's very little (less than
100 bytes) that looks unused in the binary. Still, though, it doesn't
take much to add the copyright. For Stampede, it's 32 bytes of graphics
storage, a 32-pixel-sprite graphics routine which'd take around 40 bytes
of code, and 8 or less bytes of RAM.
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