forums.ps2dev.org

PeterM · Joined: 31 Dec 2005 Posts: 125 Location: Edinburgh, UK

Hello,

I'm attempting to port a game to PSP, and for some reason, the fread function has problems with large files. With a file on the memory stick which is around 2MB in size, the following call:

FILE* file = fopen("./myfile.dat", "rb");
int read = fread(buffer, 1, 65536, file);

returns 16384 instead of 65536. Subsequent calls return 0. Has anyone seen this problem before?

I'm not sure where to look for the source for fread, apologies if I'm doing something stupid...

Peter

PeterM · Joined: 31 Dec 2005 Posts: 125 Location: Edinburgh, UK

This may actually be a memory card corruption problem for me only - copying files onto the PSP via USB in a different order moves the problem to a different file.

On some files the PSP locks up completely.

CyberBill · Joined: 26 Jul 2005 Posts: 86 Location: Redmond, WA

Have the PSP do a format on the memory stick and give it another go

I have had VERY strange problems with a memory stick that have been solved this way, due to corruption.

PeterM · Joined: 31 Dec 2005 Posts: 125 Location: Edinburgh, UK

Thanks for the tip. I tried it out earlier (backing up my game saves, formatting the card, then restoring the saves) and it seems to have helped.

I still get the occasional problem though - e.g. files refusing to delete from the memory stick - I think my memory stick is knackered...

Thanks again for the advice.

CyberBill · Joined: 26 Jul 2005 Posts: 86 Location: Redmond, WA

The PSP is really... strange... in the way it handles file IO.

For instance, when doing any disk IO you can pass in a 'repeat' factor that says how many times to retry something, because it doesnt always work.

So, I say you call it until it does what you want. But thats just me :)

av · Joined: 01 Jan 2006 Posts: 7

I just spent 4 hours working through other file read related hang problems. You may want to try changing your Makefile to compile with -O1 instead of -O2. -O1 will do less optimization. However, -O2 seems to cause my app to hang the PSP if I change a line of code from time to time (I think gcc's optimizations are a little busted on the PSP). With -O1 everything seems to work as expected.

mrbrown · Joined: 17 Jan 2004 Posts: 1536

av · Joined: 01 Jan 2006 Posts: 7

Jim · Joined: 02 Jul 2005 Posts: 487 Location: Sydney

Looks more like a stack overflow/corruption.
Jim
_________________
http://www.dbfinteractive.com

jimparis · Joined: 10 Jun 2005 Posts: 1179 Location: Boston

groepaz · Joined: 01 Sep 2005 Posts: 305

the fact that it works on windows isnt really proof either, windows can be very forgiving when it comes to broken code (how else would it even boot? :=D)
_________________
http://www.hitmen-console.org
http://hitmen.c02.at/files/yapspd/