Re: A82: Galaxian bug... solved?
[Prev][Next][Index][Thread]
Re: A82: Galaxian bug... solved?
you are correct
~Adamman
In a message dated 98-04-15 14:55:32 EDT, you write:
> Being a novice asm programmer, i may be wrong, but shouldn't you
> actually use 767 instead of 768? it seems to me that when you ldir, if
> you use 768, de will end up writing one beyond graph_mem, since it
> started one into graph mem. anyway, just a question.
>
> - Bryan Catanzaro
>
> Barubary wrote:
> >
> > Umm... I think I might've figured it out. I KNOW this is a
> > bug - I just don't know what it does. I don't even know what
> > the problem with running it in crash IS... Evil Sam, could
> > you try this fix and see if it clears it up?
> >
> > This code is simply wrong. GRAPH_MEM is 768 bytes, not 960.
> > ((96 * 64) / 8 = 768) You're overwriting something in RAM,
> > and to be accurate I don't know what the hell you're
> > overwriting, but I KNOW something is glitched here: :)
> >
> > ld hl,GRAPH_MEM
> > ld de,GRAPH_MEM+1 ; this clears the damned graph memory
> > ld bc,960
> > ld (hl),0
> > ldir
> >
> > Change 960 to 768 and try that. If that doesn't fix the
> > problem, LEAVE IT IN. It won't hurt to not do something that
> > can seriously fuck up system RAM :)
> >
> > -- Barubary