Fix some UB in movie_lib.cc

[glebm]

Fixes warnings shown by UBSAN during the title movie playback. Mostly misaligned loads and a couple of bad shifts.

This fixes the game crashing on startup on rg350m.

[glebm]

@alexbatalov Can you please take a look at this PR?

[alexbatalov]

Thanks for pinging. Will look today.

[alexbatalov]

I've refactored your code a bit to match surroundings, hope you don't mind. movie_lib needs complete review, so it should not have too much dependencies. Thanks.

[glebm]

Thanks, looks good overall, but I'm wondering what the purpose of these is:

if (1) {

[KulikAlex]

@glebm @alexbatalov Why doesn't getOffset work?
#136

[KulikAlex]

@alexbatalov is there any information about the _nfPkDecomp? how did you decompile?

[glebm]

Why doesn't getOffset work?

My original getOffset looked like this:

    constexpr auto getOffset = [](uint16_t v) {
        return static_cast<int8_t>(v & 0xFF) + dword_51F018[v >> 8];
    };

The refactored one is like this:

uint8_t getOffset(uint16_t v)
{
    return static_cast<int8_t>(v & 0xFF) + dword_51F018[v >> 8];
}

The difference is the return type, that's probably why. It should probably be int.

[giuliano-macedo]

Hey, I'm pretty sure this PR caused #194

[glebm]

@alexbatalov As I mentioned in #117 (comment), the return type here (changed from auto to uint8_t when merging) is incorrect, it should be int or int32_t. This caused #136.