>Actually, with z26, when it's doing background or playfield, and that's what
>it's doing most of the time, it's 3/8 of an instruction per pixel, two
>32-bit stores in a row, then we increment the pointer by 8. At first
>glance, I don't see a way to do a left-pixel right-pixel kind of thing
>without slowing it down by a fair amount. Of course, that doesn't mean a
>way doesn't exist.
Is this with pixel doubling, so that the low two bytes of the 32 bits are
equal, and the high two bytes are equal? (if the 32 bits are in EAX, then
AH=AL, and the top two bytes of EAX are also equal.) In that case, you've
got two 2600 pixels per 32-bit store. For tweaked mode, you'd just need to
write AL to the screen, SHR EAX,16, write AL to memory, increment counter.
>If you start out doing 320 by 200 tweaked, once the addressing and rendering
>issues are resolved, it's a small step to 320 by 240 or 360 by 240. I want
>one or the other of these modes because then you can display a tall game.
True. And you can get to 480 lines, so you can get the venetian-blind
effect for tall games too. Why would you want 360 across for a 2600
emulator, though? 320x480 is perfectly doable, even if it has the worst
aspect ratio since 640x200 mono CGA :)
>Although most games fit in 200 scan lines, many of them don't. Even combat
>doesn't really fit. Also, modes that are 240 scan lines tall, refresh at 60
>Hz. Then instead of fighting a 70Hz monitor trying to get it to play a 60
>Hz game, you can synchronize the game with the monitor AND get correct play
>speed. Many visual artifacts disappear when the game is synchronized with
>the monitor.
Do they? That'd be nice too.
>http://www.whimsey.com/z26.html
>
>I'll be posting version 0.89 shortly, but there are no differences in the
>graphics so you could still start getting an idea about how things work
>anyway. The rendering engine is found in a file called tia.asm. I would be
>very happy for you take a shot at it!
Got the source. Er, what compiler and assembler exactly are you using...
also, where's the part that puts it into VGA mode, so I can change that to
mode-X? I could find it myself, but it's easier to ask you :)
I haven't done x86 assembly for a while.. looking at this, it feels like a
high-level language compared to 6502 assembly, though :) Damn, the 2600
would be easier if we could do stuff like CALL [TIAREGVECTOR + EBX*2] :)
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