forums.ps2dev.org

[willow :--)]

For a school project I have to relocate a prx.

After a few tests I realized that some reloc addresses in some homebrews are not word aligned. I saw that tools such as prxtool and jcpsp don't care about those misaligned relocs and treat them as the others. Which works because the PC architecture they run on doesn't seem to care about word alignment.

However when trying that on the PSP, the PSP fails because the address to relocate is not 4 bytes aligned.

Now, If I follow what prxtool and jcpsp do (a.k.a work as if word alignement didn't matter), the idea is to overcome the psp limitation by reading 8 bytes, relocating inside this array of 8 bytes, and putting the 2 words back.

Before:
N+0:XX XX YY YY
N+4:YY YY XX XX

After
N+0:XX XX ZZ ZZ
N+4:ZZ ZZ XX XX

(imagine that the stuff I have to relocate are those YY YY YY YY at N+2. If I ask the PSP to grab the word at N+2, it will crash )

Now... isn't it weird that gcc generates relocs that are not word aligned? Am I missing something?

I'm not an expert at that, but I also wonder how the PSP handles misaligned relocs when it relocs with hardware. And obviously, it does handle the case since the homebrews I'm testing do run on a cfw psp
_________________
Wagic. Play that card game against an AI on your PSP

[TyRaNiD]

Relocs should at least be 2 or 4 byte aligned depends obviously on the reloc.

[willow :--)]

but isn't even a 2 byte alignment a problem from the PSP's hardware point of view?
_________________
Wagic. Play that card game against an AI on your PSP

[m0skit0]

Not if you're using lh instruction. It's a problem if you use lw.
_________________

[m0skit0]

Not if you're using lh instruction. It's a problem if you use lw.
_________________