Re: [stella] Qb: BETA 1.0

Subject: Re: [stella] Qb: BETA 1.0
From: "Andrew Davie" <adavie@xxxxxxxxxxxxx>
Date: Sun, 4 Mar 2001 00:10:57 +1100
> > I have about 4 bytes free, so if...

Thanks to Thomas for the suggestions - some of which I've used.

> 1. There are several subroutines (SetFrame,
> CountDown...), where you can do something like this:
>
> SoundOff
>     ldy #SOUND_OFF
>     .byte   $2c             ; bit.w
> SoundSliding
>     ldy #SOUND_SLIDING
> Sound

... sneaky.  I've not used this yet, as I've only JUST understood it.  Got
the flu :(
On the subject of understanding, I'm still trying to wrap my mind about
Thomas's suggestion for the efficient sprite-draw, where he used an illegal
instruction.

> If you document the state of registers and flags when
> returning you might find some more.

Yes, am doing that.  Good idea.

> 9. exchange x and y here:
> ZapPF   sta playfield,y

I'm not sure what you're suggesting, and why, on the above.  Due to absolute
addressing??

> 10: replace:
> MTADone
> ;->64
>         ldx #3
>         jsr MBlock
>         jsr MBlock
>         jsr MBlock
>         jsr MBlock
>
>    with:
>         jsr MB4a

That was why the MB4a routine was created, but unfortunately the jsr 6-cycle
penalty causes the screen timing to glitch... I don't think I'll be able to
do this one, which is a shame.

> > But now, I think things are getting pretty tight :)
>
> Yes, I think there aren't many more byte optimizations
> left. Maybe with some redesign of larger parts of code


The strange thing is, I've thought savings were very unlikely for the last
few version (since before the title screen).   However, since my last
source-code post (4 bytes free) I have now found LOTS of savings, and have
85 bytes free (!!).  And that is WITHOUT redesigning any of the code.  This
should, IMHO, be enough to enable me to graduate the difficulty nicely.

Perhaps, just maybe, I can add a few sounds - that would be nice.

Cheers
A

--
 _  _  _| _ _        _| _    * _                               _  ,
(_|| )(_|( (/_\/\/  (_|(_|\/(_(/_                           ,~' L_|\
                                                         ,-'        \
see my Museum of Soviet Calculators at                  (            \
http://www.taswegian.com/MOSCOW/soviet.html              \    __     /
                                                          L,~'  "\__/
                                                              @--> v


-
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/

Current Thread