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dzer0 · Joined: 29 May 2005 Posts: 15

Ok so i was poking around in that new extracted 1.50 firmware file with a hex editor and i found something very interesting:

mrbrown · Joined: 17 Jan 2004 Posts: 1536

http://pspdev.ofcode.com/api.php?type=2&id=101

dzer0 · Joined: 29 May 2005 Posts: 15

ahh ok sorry bout that :) but i wonder what the kernel needs to decompress anyway?

Shine · Joined: 03 Dec 2004 Posts: 728 Location: Germany

rasmus · Joined: 21 Jul 2004 Posts: 17 Location: G�teborg, Sweden

It is used in LoadExecAction right before rebooting. I _think_ it unpacks a fresh kernel image.

(LoadExecAction is the meat of the LoadExecBody worker thread started by sceKernelLoadExecThread, which does the work of the well known sceKernelLoadExec :)

TyRaNiD · Joined: 18 Jan 2004 Posts: 918

Well while you don't see it most prx files are gzip compressed inside, you can actually extract some of the compressed versions of some of the kernel modules by throwing them in sceKernelCheckPspConfig. There are other place it is used no doubt.

Strangely enough though the only modules which directly import the function are releated to the ME boot strap so it is really just there for fun :)

skippy911 · Joined: 06 May 2005 Posts: 46

I have been working on the compression libs for the psp and will post something tonight of what i have gotten done :) DUnno how useful it is but at least a few more functions will have been defined with parameters.

mrbrown · Joined: 17 Jan 2004 Posts: 1536

skippy911 · Joined: 06 May 2005 Posts: 46

uchar out[100*100];
uchar in[100*100];
int output;

output = sceGzipDecompress(out, 10000, in, 0);

Basically it works just like regular opening of a gzip file so you have an array of data which is held in the out array. I dont have a working example but this should work just fine. I based the function params off of zlib example i found for vb. Enjoy :D

Oh yah the 10,000 is just the 100*100