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Monte Carlos
Registered: Jun 2004
Posts: 351 |
Event id #2417 : First CSDb "Unintended OpCode coding challenge"
So here it is. The First CSDb "Unintended OpCode coding challenge" starts over.
First CSDb "Unintended OpCode Coding Challenge"
Please give some feedback about your interest in this compo.
For those who have been part of the discussion
http://csdb.dk/forums/?roomid=12&topicid=112819#112927
please let me know if you are in better agreement with the reworked rules than before.
However, there will not be a rule change anymore. |
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Monte Carlos
Registered: Jun 2004
Posts: 351 |
lax blabla,x (y)
sbx #..
should emulate cpx,y or cpx,x |
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chatGPZ
Registered: Dec 2001
Posts: 11157 |
but since that destroys akku, you can just aswell use
txa
cmp bla,y
:) |
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Oswald
Registered: Apr 2002
Posts: 5032 |
yeah I wanted to keep A intact :) |
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Rastah Bar
Registered: Oct 2012
Posts: 336 |
In the special case that 'bla' is on a page boundary (for example $1f00):
sty label+1
label:
cpx $1f00 |
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Oswald
Registered: Apr 2002
Posts: 5032 |
yup that would work, but probably also be slower or on par with what I wanted to optimize. |
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Rastah Bar
Registered: Oct 2012
Posts: 336 |
Code optimization is hard ... |
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Oswald
Registered: Apr 2002
Posts: 5032 |
yeah, well often it is good to try to find a better solution instead of fucking the illegals :) |
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Monte Carlos
Registered: Jun 2004
Posts: 351 |
let's JAM |
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Rastah Bar
Registered: Oct 2012
Posts: 336 |
One potential use of SAX, SHA, SHX, and SHY could be in border graphics ($d020, $3fff, $39ff).
With something like
lda #value1
ldy #value2
ldx #value3
sta $d020 ;or $3fff or $39ff when the ECM bit is on
stx $d020
sty $d020
sta $d020
stx $d020
sty $d020
... ; repeat the above
the result will be columns of 4 characters wide, but only three different values are used. If you want to change a color with an lda #value4, for example, one column will become 6 characters wide. But with the mentioned UOCs you can change the color/value to create a column of only 5 characters wide (4 even with SAX), although the range of value4 may be very limited. |
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T.M.R
Account closed
Registered: Dec 2001
Posts: 749 |
Yays, i was the first entry! Now watch everyone else turn up and completely nuke mine! =-) |
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