As far as timing goes, I've had good luck with it. Adventure allready
flickers if there are more than two items on the screen so any extra flicker
I make is unnoticeable I guess. I've removed code for checking black and
white which is like 4-6 clock ticks and the game still works normally.
Your fix worked, I'm able to move code around at will with no changes to
the gameplay. I've gathered up over 100 bytes of free space on the cart
right now.
Thanks for all your help, I'll post the code up here soon, once I bring it
from home.
----- Original Message -----
From: "Brian Prescott" <bprescot@xxxxxxxxxxxxxxx>
To: <stella@xxxxxxxxxxx>
Sent: Thursday, June 06, 2002 6:16 PM
Subject: RE: [stella] Adventure, Another Issue (Thanks for yesterday)
> Joel:
>
> As you are already aware (or will be very soon!), programming on the 2600
> requires an acute awareness of cycle counting (for positioning player
> graphics, drawing interesting backgrounds, etc.). Since a step across a
> page boundary uses an extra cycle in code as well as when stepping through
> data, it is possible that you can, in the process of adding or removing
> code, cause an unexpected or out of place cycle to creep into timing
> sensitive code.
>
> This happened to me many times on my two finished projects, and also when
I
> was modifying some old Activision code. I haven't looked extensively into
> the structure of the Adventure code (I was lucky to find the fix quickly,
> BTW did it work for you?), but it may be set up in a way that there is no
> timing sensitive code near any page boundaries.
>
> BP
>
> -----Original Message-----
> From: owner-stella@xxxxxxxxxxx [mailto:owner-stella@xxxxxxxxxxx]On
> Behalf Of Joel Park
> Sent: Tuesday, June 04, 2002 9:00 AM
> To: stella@xxxxxxxxxxx
> Subject: Re: [stella] Adventure, Another Issue (Thanks for yesterday)
>
>
> Brian,
>
> Thanks for the fast reply.
> And for the huge help, I'll try this stuff out tonight.
>
> What you were mentioning about PageBreaks... As long as I keep all the
room
> data within one "High" range I should be ok right?? Like as long as it's
> between FE00 and FEFF I shoud be fine, right. (Sorry for such a newbie
> question.)
>
> Thanks to all you guys, I really appreciate how helpful everyone is.
>
>
>
> ----- Original Message -----
> From: "Brian Prescott" <bprescot@xxxxxxxxxxxxxxx>
> To: <stella@xxxxxxxxxxx>
> Sent: Tuesday, June 04, 2002 8:39 AM
> Subject: RE: [stella] Adventure, Another Issue (Thanks for yesterday)
>
>
> > Joel:
> >
> > The problem is in the RoomNumToAddress subroutine. This routine
> calculates
> > an address into the room data table. By adding a byte to the arrow
> graphic,
> > these addresses are all off by one.
> >
> > In the subroutine, you can change the final bit of code to this:
> >
> > LDA #<RoomDataTable
> > CLC
> > ADC $93 ;Add the room data base address
> > STA $93 ;to the offset therefore getting
> > LDA #>RoomDataTable ; the final room data
> > address.
> > ADC $94
> > STA $94
> > RTS
> >
> > And of course, add the RoomDataTable label at FE1B.
> >
> > When you do this kind of thing in the actual code instead of the table
> data
> > at the end, you also need to be aware that page breaks can and do cause
> the
> > code to go haywire. I found this out in some of my own disassemblies
and
> > code modifications.
> >
> > BP
> >
> > -----Original Message-----
> > From: owner-stella@xxxxxxxxxxx [mailto:owner-stella@xxxxxxxxxxx]On
> > Behalf Of Joel Park
> > Sent: Tuesday, June 04, 2002 8:04 AM
> > To: stella@xxxxxxxxxxx
> > Subject: [stella] Adventure, Another Issue (Thanks for yesterday)
> >
> >
> > Once I got a newer version of DASM, I was all ready to go and everything
> > worked great and I thought I had all the labels added, But...
> >
> > It still looks to be accessing memory directly somewhere instead of
using
> my
> > labels but for the life of me I can't find it.. I've been through the
code
> > multiple times, line per line and can't find any place that would be
> giving
> > me problems.
> >
> > Here is what I do to test.
> >
> > I went to the graphic for the Sword and added an extra line of graphics
in
> > the middle, to make it higher. Then I go clear to the end and there
are
> > like 9 bytes that are labeled as "Unused", I remove one of them to keep
my
> > program 4K.
> >
> > When I compile and run, the whole game is freaking out.. The issue
seems
> > to be related to the dynamic backgrounds and not my sprites because they
> all
> > look fine and any changes I make to them are visible.. But the
background
> > are pretty much all gone and it's just a garbled mess nearly impossible
to
> > navigate.
> >
> > The version of the code I attached has all the lables and everything and
> > still compiles. Could someone check it out and see if I missed
something
> > when adding lables or something.. There may be an assembler command
that
> is
> > setting the high byte of my memory addresses and I'm just not picking it
> out
> > or something.
> >
> > Thanks,
> > Joel D. Park
> >
> >
> >
> >
>
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