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Atari demoscene BBS
| Re: Gauntlet thrown down? |
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Posted by: Kalms
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Mar,06.2007-00:37
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Brief quantitative analysis.
Example Atari ST tunnel-routine innerloop:
moveq #0,d0
move.w xx(a0),d0
or.w xx(a1),d0
or.w xx(a2),d0
or.w xx(a3),d0
lsl.l #2,d0
move.l xx(a4,d0.l),d1
movep.l d1,(a5)
moveq #0,d0
move.w xx(a0),d0
or.w xx(a1),d0
or.w xx(a2),d0
or.w xx(a3),d0
lsl.l #2,d0
move.l xx(a4,d0.l),d1
movep.l d1,1(a5)
Disadvantage here is that texture needs 1 word/pixel and 4 unique copies, plus 256kB pixel scrambling table. That's quite a lot of
data if you want to fit into 1MB...
Example Amiga tunnel-routine innerloop (sp^ctz style):
move.b xx(a0),d0
or.b xx(a1),d0
move.b d0,(a2)+
move.b xx(a0),d1
or.b xx(a1),d1
move.b xx(a0),d0
or.b xx(a1),d0
move.b d0,(a2)+
move.b d1,(a2)+
move.b xx(a0),d0
or.b xx(a1),d0
move.b d0,(a2)+
+ 1 blitter-pass (24kB extra mem-access)
+ bitplane-DMA for 5th bpl (8kB extra mem-access per frame)
Texture needs just 2 unique copies, with 1 byte/pixel. No pixel scrambling table.
The Amiga routine will have the "ghosted" look, due to every other pixel containing garbage data. 100% correct results can be obtained through another 24kB of blitter mem-access.
Alternative Amiga tunnel-routine innerloop:
move.w xx(a0),d0
or.w xx(a1),d0
or.w xx(a2),d0
or.w xx(a3),d0
movep.w d0,(a4)
move.w xx(a0),d0
or.w xx(a1),d0
or.w xx(a2),d0
or.w xx(a3),d0
movep.w d0,1(a4)
+ 1 blitter-pass (16kB extra mem-access)
+ bitplane-DMA for 5th bpl (8kB extra mem-access per frame)
Texture needs 4 unique copies, with 1 word/pixel. No pixel scrambling table.
I'm not sure offhand which is the fastest of the three.
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Topic
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Posted by
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Date
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Gauntlet thrown down?
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CiH
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Feb,28.2007-19:52
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Re: Gauntlet thrown down?
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Carbon
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Mar,01.2007-14:28
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Re: Gauntlet thrown down?
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Paranoid / Paradox
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Mar,01.2007-21:45
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Re: Gauntlet thrown down?
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ggn
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Mar,02.2007-00:40
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Re: Gauntlet thrown down?
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tobe
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Mar,02.2007-14:18
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Re: Gauntlet thrown down?
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Peter
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Mar,02.2007-15:59
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Re: Gauntlet thrown down?
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ggn
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Mar,02.2007-18:59
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Re: Gauntlet thrown down?
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evil
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Mar,02.2007-21:01
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Re: Gauntlet thrown down?
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tobe
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Mar,05.2007-11:15
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Re: Gauntlet thrown down?
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Kalms
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Mar,06.2007-00:37
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Re: Gauntlet thrown down?
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ggn
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Mar,07.2007-15:28
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Re: Gauntlet thrown down?
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Kalms
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Mar,08.2007-12:29
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Re: Gauntlet thrown down?
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calimero
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Mar,06.2007-00:37
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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