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Atari coding BBS
| Re: 4 pixel rasters |
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Posted by: ultra
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Jun,09.2006-10:17
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hi crea,
yes i did yesterday some more test... and came to the same conclusion...
the "effect" just changes the background color
means:
a0 = $ff8240
d0 = $600
d1 = $000
so a:
add.w d0,(a0)
move.w d1,(a0)
produces a 4 pixel colorswitch...
the odd clockcycle count i already discovered is not resposible
for this... tried it with add.l which has a even count. which did not produce
a 4 cycle switch it was a 8 pixel one...
something like
lea $ff8240,a0
lea $ff8242,a1
add.l d0,(a0)
move.w d1,(a1)
ok this changes color #1...
but anyway the idea was rubbish
was you can see in your list:
0 nop - prefetch [ add.w d0,(a0) ]
1 add - read data from (a0)
2 add - prefetch [ move.w d1,(a0) ]
3 add - write-out color is changed after this writeout
4 move - write-out color is changed after this writeout
5 move - prefetch [ add.w d2,(a0) ]
6 add - read
7 add - prefetch [ move.w d3,(a0) ]
8 add - write-out
so quite logical 4 pixel colorswitch ...
i was wondering why it does not work when you do something like this:
move.w d0,(a0)
move.w d1,(a0)
this produces a 8 pixel switch...
but this is quite clear... (hope this is correctly)
0 nop - prefetch [ move.w d0,(a0) ]
1 move - write-out [ move.w d0,(a0) ] color is changed after this writeout
2 move - prefetch [ move.w d1,(a0) ]
3 move - write-out [ move.w d1,(a0) ] color is changed after this writeout
4 move - prefetch [ move.w d0,(a0) ]
....
so the explanation why it produces a 4 pixel colorswitch is that add prefetches the
move already when the add is executed... this is not possible in the move...
for example it works too with:
eor. w d0,(a0)
move.w d1,(a0)
same as add...
i hope i got it know correctly ;))
ultra
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Topic
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Posted by
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Date
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4 pixel rasters
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ultra
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Jun,08.2006-00:40
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Re: 4 pixel rasters
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ultra
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Jun,08.2006-00:43
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Re: 4 pixel rasters
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evil
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Jun,08.2006-08:20
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Re: 4 pixel rasters
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ultra
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Jun,08.2006-08:45
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Re: 4 pixel rasters
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earx
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Jun,08.2006-08:55
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Re: 4 pixel rasters
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earx
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Jun,08.2006-08:56
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Re: 4 pixel rasters
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utlra
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Jun,08.2006-09:00
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Re: 4 pixel rasters
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ultra
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Jun,08.2006-10:17
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Re: 4 pixel rasters
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ultra
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Jun,08.2006-11:02
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Re: 4 pixel rasters
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earx
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Jun,08.2006-11:20
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Re: 4 pixel rasters
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ultra
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Jun,08.2006-11:37
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Re: 4 pixel rasters
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earx
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Jun,08.2006-16:35
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Re: 4 pixel rasters
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Creature XL
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Jun,09.2006-09:31
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Re: 4 pixel rasters
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ultra
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Jun,09.2006-10:17
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Re: 4 pixel rasters
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ultra
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Jun,09.2006-10:36
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Re: 4 pixel rasters
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Leonard
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Jun,13.2006-10:27
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Re: 4 pixel rasters
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alien st/cnx
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Jun,15.2006-18:34
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Re: 4 pixel rasters
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Leonard
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Jun,19.2006-11:12
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Re: 4 pixel rasters
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alien st/cnx
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Jun,21.2006-03:08
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Re: 4 pixel rasters
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Leonard
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Jun,21.2006-17:26
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Re: 4 pixel rasters
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evil
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Jun,21.2006-18:30
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Re: 4 pixel rasters
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ggn/KUA
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Jun,22.2006-08:48
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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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