VFPU lv.q and ulv.q about pspsdk HOT 2 CLOSED

I read PSP 1000 has a problem in the VFPU, it looks like the instruction "ulv.q" is broken. Is that true?.

I didn't remember, but that seems to be true as of this thread: http://lukasz.dk/mirror/forums.ps2dev.org/viewtopicf96b.html
What hlide wrote there is absolutely trustworthy, as we both digged into the VFPU instructions back then. He was maybe one of the most experienced homebrew devs around regarding VFPU code.

I'd really like to know more about this, and why lv crashes so much.

As you stated, lv is an aligned access operation. Trying to access unaligned memory with that operation will inevitably crash. So you need to make sure every memory location accessed through those ops is correctly aligned. The biggest issue is probably the stack variables.

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Thanks a lot!.
Then I'll have to get rid of all "ulv" and use lv. I'll test all possible alignments with attribute((aligned(value))).

It helps a lot that PPSSPP is emulating the psp so well, that "lv" crashes like the real console, if not used properly.

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