Please help me with code that doesn't understand the principle at all.

[Vega]

Code:

lfs f0, -0x7B68(r2)

r2 = rtoc = Register Table of Contents. It's contains a Mem Address that points to the Table of Contents. Each Wii Game will have different contents at their TOC.
The contents in Smash is diff than MKWii.

You will have to set r3 manually to an integer value. Therefore, you no longer need the following code...

Code:

lfs f0, -0x7B68(r2)
fmuls f0, f0, f30
fctiwz f0, f0
stfd f0, 0x8(r1)
lwz r3, 0xC(r1)
rlwinm r3, r3, 0, 24, 31

The double float store-load at r1 + 0x8 is probably what's causing the crash. You're storing to the older Frame which must remain intact. Regardless, it doesn't matter since you can set r3 via an integer.

Code:

li r3, 0xXX

r3 can only be a byte value. It's likely the byte value range is 0x00 thru 0xFF.