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Bacchus
Registered: Jan 2002
Posts: 154 |
Replacing games loader ...
OK, this on cracking but still highly related to coding.
Most games I fiddled with over the year call the loader using a parameter that was the index of the file. Using the same parameter as index for my IFFL or converting it to a two byte string starting the file name has worked well for me in most cases.
I am now facing two games that are not distributed yet (old, but no scene version is out) where there is a lot of data stored directly on the disk and the game then loads it using direct track and sector. Think of it like action adventures. The game loads strings or other really small things by loading T/S and then exctacting the needed part. It's hence not really "files" most of it and there are so many that a file per string is plainly not within reach.
I can think of a few approaches;
1) Keep it as data on disk. Allocate the sectors used and then store the files on the unallocated sectors. You can't compress it - it does take a full disk side any way you look at it. It does work, looks rather neat but cannot be counted as a firstie.
2) Make a big chunk of the data to a file and push it to a REU the first thing you do. The game become ever so much more playable and fast. And the file can be compressed efficiently. You do need a REU (or simply enable it in your emulator or Ultimate Cart) but it's also still not counted as a firstie.
3) Make a big file which you then need to scan as the original 256 byte sectors are now 254, so a sector that was a full page is by necessity spread over two sectors in a file based option. I guess you can also compress the sectors individually and think of the sectors as files in an IFFL. One IFFL file equals a sector. This is an ugly bitch but could be counted as a firstie.
Any other thought on this technical challenge? I must admit I am growing fond of the REU option, and the firstie restriction is the only thing that holds me back. The Tink games we just released had been perfect in REU version. Would have saved SO much work, loading would have been near instant and it would have been a release of two neat files.
Am I missing any options or can someone provide some lateral thinking, that opens up new options by finding approaches I have missed? |
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Knight Rider
Registered: Mar 2005
Posts: 114 |
is .d81 out of scope for points ?? |
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Bacchus
Registered: Jan 2002
Posts: 154 |
Points are only awarded for stuff that runs on stock 64. |
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Tim
Account closed
Registered: Mar 2002
Posts: 467 |
Bacchus,
I'm not qualified to answer your question, but I do acknowledge the problem.. in some cases it's actually the reason why some releases are not done yet.
Good luck in Fairlight's attempt to combine points and quality, it is noticed, and it is respected.
Side note;
Having to make similar choices in our crew frequently, it is no secret that if you (or anyone for that matter) would start a quality rating system, it would certainly mean we shift even more resources in that direction. |
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chatGPZ
Registered: Dec 2001
Posts: 11102 |
Quote:For the sake of argument; let's assume five files of 20 blocks and then 400 "256 byte pages". That makes a total of 500 blocks.
you are missing "how much memory is there to use for it".
eg: your example is pretty trivial if you have 800 bytes for an index table |
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Bacchus
Registered: Jan 2002
Posts: 154 |
You rarely have memory - you claim it ;)
Still, IMHO tables for over 256 is less trivial. Forget drive RAM. 400 files means 1200 bytes tables. Track, sector and offset. Times 400. That sort of memory is not common in any game. |
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ChristopherJam
Registered: Aug 2004
Posts: 1370 |
…so then perhaps for each group of 4 source blocks, have the track/sector/offset of a record in the IFFL that itself contains four lightly compressed blocks, preceded by a header giving the compressed length of each of the four?
Then you only have 300 bytes of tables, 200 if you pad each group of four to a block boundary.
Of course, then you might have to read as many as three extra blocks, but they should all be on the same track most of the time.
(apologies if my terminology is off; I have zero experience in cracking, obviously) |
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Bacchus
Registered: Jan 2002
Posts: 154 |
If the compressed sectors fit on the same physical sector, the loading wouldn't be too delayed.
I agree this is a validated way forward. It's sort of a more detailed line of thoughts as per what was already provided above. |
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Mason
Registered: Dec 2001
Posts: 459 |
Well depending on the number of files on the tracks
You can find out how much room you got for buffer in memory - if it's $0800 and you can compress the files into $80 bytes then you load in chucks in $0800 - that would be 16 files
16 x 128 in the IFFL would make it possible to store 768 packed $80 files in $0800 chucks. To unpack use the method like old Level Crueler where you load the packed files into memory and depacked it afterwards |
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JackAsser
Registered: Jun 2002
Posts: 1987 |
If you have >256 files then you already reference the file table via 16-bit value in the code. Why is a table needed at all? Why not provide the t/s/off/size directly in the code when needed? |
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Martin Piper
Registered: Nov 2007
Posts: 631 |
Quote: If you have >256 files then you already reference the file table via 16-bit value in the code. Why is a table needed at all? Why not provide the t/s/off/size directly in the code when needed?
Depends on the level of the code hook I suppose. Conversion from the old track/sector to the new track/sector/pos table could change less in the calling code. |
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