Resource centre for ZX Spectrum games
using Manic Miner and Jet Set Willy game engines
Archive of the
Manic Miner & Jet Set Willy Yahoo! Group
messages
|
|
|
|
|
Message: 5906
Author: andrewbroad
Date: 20/08/2006
Subject: Re: Finding unused addresses in JSW
jgh@... wrote:
>Unfortunately, this is one of the conditions by which JSWED
> Could I suggest to the JSW patching community the following
> convention:
>
> If &8451-&8453 does not contain "AIR", then it is a "spare space
> index".
recognises a JSW game: if you change the contents of #8451-8453,
save it and reopen the file in JSWED, it only gives you access to
the hex-editor!
> I would also suggest that &858B-&85CA be used for data andI say free space is free space, and I tend to put a new patch in the
> &869F-&87C9 be used for code, following the layout of the JSW48
> game engine itself.
lowest free address-range it will fit.
That said, it can be useful to have standard recommended addresses
for commonly-used patches, so that .HEX files (and the like) can put
multiple patches in non-overlapping address-ranges without user-
intervention.
> I would also recommend patches not be put in the rooms area, thisAbsolutely - rooms should be the last thing you sacrifice to make
> is space more valuable as rooms,
space for a patch! (Tell that to Softricks, or to JSWED's interface
for applying the teleport-patch to JSW48.)
> and not in the sprites area, this is more valuable as sprites.Any page in (the 64K of addressable) memory can be used as a sprite-
page (a fact which the current revisions of JSWED fail to respect),
so there's no technical reason why patches shouldn't go in addresses
usually used for sprites - although it should be noted that a
horizontal-guardian sprite requires one whole page of memory to
itself, and so on.
(/page/ A 256-byte contiguous block of memory whose start-address is
divisible by 256; in other words the high byte of every address
within that block, e.g. page #A6 = addresses #A600-A6FF.)
--
Dr. Andrew Broad
http://geocities.com/andrewbroad/
http://geocities.com/andrewbroad/spectrum/
http://geocities.com/andrewbroad/spectrum/willy/
|
|
|