Re: Double-Width HiRes

[russotto@wanda.vf.pond.com (Matthew T. Russotto)]

In article <38313576.E5F82CB3@swbell.net>,
Rubywand  <rubywand@swbell.net> wrote:
}Jon Bettencourt writes ...
}
}<Rubywand wrote ...>
} ....
}> >
}> >  the Aux bank part  is in $2000-$3FFF
}> >  the Main bank part is in $4000-$5FFF.
}> >
}> > All of this is, naturally, in Main bank memory.
}> >
}> >
}> >      To display the above pic in 'DHR page 1', you move $2000-$3FFF from
}> > Main bank to $2000-$3FFF in Aux bank. Then, you move $4000-$5FFF in 
}> > Main bank to $2000-$3FFF in Main bank and turn ON the display with
}> > softswitches.
}> 
}> Is this how DazzleDraw pictures are stored? Or are they stored main-memory
}> part first, like I assumed in the first place? The 16K file that I want to
}> load into double hi-res is a DazzleDraw file.
} ....
}
}     The Aux bank part is in $2000-$3FFF and the Main bank part is in
}$4000-$5FFF. This is pretty much the standard way of storing DHR pics. (Think
}Beagle used to store the parts of the pic in separate files. That idea never
}really became popular.)
}
}     Although the storage order requires an extra move if you display from 'DHR
}page 1', it requires just one move if you display from 'DHR page 2'.

You can't display from DHR page 2.  The reason the DazzleDraw pictures
store AUX first is likely because it requires one save and no copies to
auxiliary memory -- you just move main page 1 to main page 2, flip
80STORE, HIRES, and PAGE2 on, and save from $2000-$5FFA.  If it were
stored MAIN first, you'd have to use AUXMOVE to get the data from
$4000-$5FFA into auxiliary memory, which would be slower due to the
overhead of copying from main memory to auxiliary memory.

To load with one copy, do the reverse -- turn 80STORE, HIRES, and
PAGE2 on, load the data into memory, turn PAGE2 off, and copy the data
from hires page 2 to page 1.
-- 
Matthew T. Russotto                                russotto@pond.com
"Extremism in defense of liberty is no vice, and moderation in pursuit
of justice is no virtue."