Re: A82: Re: Re: Assembly-82 Digest V1 #702
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Re: A82: Re: Re: Assembly-82 Digest V1 #702
I can not belive i did not catch that when I was going through your code !
The strange thing is that this shoudl cause the dtbl value to be changed as
soon as you start boulderdash, but apparently this does not happen. Have you
checked that this solves the problem ?
Dines
----- Original Message -----
From: Sam Heald <evil_sam@hotmail.com>
To: <assembly-82@lists.ticalc.org>
Sent: Sunday, May 09, 1999 11:18 PM
Subject: Re: A82: Re: Re: Assembly-82 Digest V1 #702
>
> >Boulderdash uses the memory before GRAPH_MEM for temporary storage during
> >the game. This area contains the dTbl value and other information like
> >that.
> >The value you mention is in the middkle of the area used by boulder dash
so
> >it is likely that other values are altered too.
> >
> >I had a look at the boulderdash source code, but could find any problems.
> >The area which is modified is backed up before it is altered and restored
> >before you exit the game. Since you have to start playing for the problem
> >to
> >occur, there has to be a line of code in the game which modifes the last
> >half of TEXT_MEM.
> >
> >Dines
>
> Actually the problem was so blatantly obvious that I feel I should
> probably smack myself. Here's an ASM intelligence test:
>
> BD startup code:
>
> ld de,GRAPH_MEM-192 ;Address of memory to restore
> ld hl,TEXT_MEM2 ;Address of save buffer
> ld bc,128 ;Number of bytes to copy
> ldir
>
> ld de,GRAPH_MEM-64 ;Address of memory to restore
> ld hl,TEXT_MEM+64 ;Address of save buffer
> ld bc,64 ;Number of bytes to copy
> ldir
> ld (iy+13),0 ;No scrolling Text
> res 1,(iy+$0D)
> ...
> Hehe. Oops :)
>
> In case you didn't catch it, my hl and de registers are switched
causing
> the data in TEXT_MEM2 and TEXT_MEM to be copied to GRAPH_MEM-192, not the
> other way around. So the TIOS data was not actually getting backed up.
> At least it's easy to fix :)
> Sam
>
>
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