[comp.sys.apple2] Double Hi-Res Graphics

cs64wbs@sdcc8.ucsd.edu (BRYAN WILLSON) (03/21/91)

I'm wonder if anyone can help me regarding Double Hi-Res graphics.
I am aware of how they operate, and I know my computer is correctly
"hardware endowed" to do dblhires, but I don't know how to bank
switch in order to work with the bank-switched auxiliary memory.
The Apple //e tech ref man is of little help.  It tells you that you
must use bank-switched memory but doesn't tell you how to access
bank c1 (as opposed to c0).  Anybody know?

Thanks in advance.

greg@hoss.unl.edu (Lig Lury Jr.) (03/23/91)

In <17670@sdcc6.ucsd.edu> cs64wbs@sdcc8.ucsd.edu (BRYAN WILLSON) writes:

>I'm wonder if anyone can help me regarding Double Hi-Res graphics.
>I am aware of how they operate, and I know my computer is correctly
>"hardware endowed" to do dblhires, but I don't know how to bank
>switch in order to work with the bank-switched auxiliary memory.
>The Apple //e tech ref man is of little help.  It tells you that you
>must use bank-switched memory but doesn't tell you how to access
>bank c1 (as opposed to c0).  Anybody know?

>Thanks in advance.

Myself, while fiddling around with the standard RAMdisk /RAM, I discovered
that one could save the secondary bank's screen to an empty /RAM and it
will be positioned perfectly.  I sent this into A+ (or was it inCider...)
and they said it didn't work on all systems, but I have yet to find one
that it didn't work on.  Much easier than having to fool around with a
special ML routine.  I wrote a simple graphics program in AppleSoft to
work with this method.  Shall I dig it up and upload it to the .binaries.
group?

--
///   ____   \\\ "I was going flat out and this thing just strolled past me,
| |/ /    \ \| |  star drive hardly ticking over.  Ten seconds later it smashed
 \\_(\____/)_//   straight into the third moon of Jaglan Beta.  Amazing-looking
ship \_\\\/ though.  Looks like a fish, moves like a fish.  Steers like a cow."

nagendra@bucsf.bu.edu (nagendra mishr) (03/24/91)

well d-hires memory resides on bank 1.
you can easily access this memory by first
enable the 80 column card.    : pr#3
next enable hires mode        : hgr
next enable d-hires circuitry : poke -16290,0
if you want to write on bank 0: poke -16300,0
if you want to write to bank 1: poke -16299,0

both banks will be on page   i.e. $2000-$4000

so you can save both pictures if you want.
			: poke -16300,0: ?chr$(4)"bsave pic,a$2000,l$2000"
			: poke -16299,0: ?chr$(4)"bsave pic.aux,a$2000,l$2000"
you have to however do these tings from a program, it will not work
from the command line. 

hope it helps
nagendra
nagendra@bucsf.bu.edu

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*     Destiny is a birth-right.      |  nagendra@bucsf.bu.edu              *
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