Version byte 0x45
Reserved section specification:
The reserved section will be gzip compressed.
A "mini" savestate is a sparsed file, which is created using saveclean (to be released). It will compare two savestates against each other, and the data found to be the same will be changed into null data. This data is then gzip compressed.
When the 2sflib is loaded, it will load the ROM as per usual, and will pause once the ARM9 and ARM7 EXE's are loaded. The savestate in the LIB is then loaded into memory but is not loaded. The loaded data is then patched with the sparse data. Bytes found to be zero will be skipped.
After this is done, boom, we have EMULATION!!@!@@1904712u0hfiaw
As for a player, I'll start with Desmume 2sf and will move outwards into Winamp from there.
Oh, by the way, RAM tracing is going to be removed from Desmume 2sf in the next build, since the tracer does not read data in the executables. So there!
Another feature I'm thinking of implementing is something similar to SPC dumping. When a command is initiated, the emulator quickly checks through RAM space, and initiates a breakpoint at what it suspects to be SND_StartSeq. When the breakpoint is hit, GX_VBlankIntr will be patched into an infinite loop, and a savestate will be made. So that will try and take the learning curve for ripping off of this, eh?
Gzip compression must be retained to individual files (for gzread()/gzwrite()/gzopen()), so I will instead have savestates be zlib-compressed.
4 bytes: char identifier = { 'S', 'A', 'V', 'E', }
4 bytes: u32 savestate_compsize
4 bytes: u32 savestate_crc32
I hate having to revise this over and over but I need an efficient way to go about doing things.
And I am considering SR64 for savestates to avoid wasting time with reading 20.3 MB of null bytes.
And here's a mockup logo:
edited 12:33 PM EST February 27, 2007
fread(uncompbuf,1,0x15F91FE,savestate);
savesize=sizeof(uncompbuf);
printf("compressing savestate\n");
if(compress2(reserved,&savesize,uncompbuf,savesize,9) !=Z_OK){
printf("zlib compress failed!\n");
return 1;
} else {
fwrite(reserved,1,savesize,tsffile);
printf("compressed savestate, attempting to compress ROM\n");
return 0;
}
Note that this version requires you to have a savestate, but I am not sure when I will have a stateless version ready. As of now the format requires a savestate to be loaded to save time with booting.
http://unknown.hcs64.com/2sf/mk2sf.cpp
Compile with whatever you like. Requires the zlib libraries to compile.
Usually, the ARM9 processor will instruct the ARM7 processor to run the sequencer. Communication between the two processors, y'know...
Anyways, expect Desmume 2sf to support actual rips sometime in the future, though it is bound to be very buggy and stupid, knowing how good I am at C...
- English essay (still incomplete)
- History essay (3 pages minimum)
- Flash presentation (30-60 seconds)
I will do most of the work on that this week, and a bit on the weekend, providing that I decide not to be lazy.
However, I will be implementing 2sf support sometime throughout this week and March Break.
Anyways, I managed to compress Kirby Canvas Curse's ROM from 64 MB to 800 kb. The savestates contain all of the sequence data that has already been loaded. On average, that data is 50 KB (with samples and all).
uncompress(&uncompressedcode,sizeof(uncompressedcode),code,codesize)
Thankfully zlib has good ways of going about safe error handling so this thing didn't blow up and die.
EDIT: 2sf.c on pastebin: blah
edited 6:31 PM EDT March 12, 2007
No, decompression and playback isn't implemented yet, it's just up here so you can see what's going on.