Re: A82: Galaxian bug... solved?


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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