* The bios uses them to initialize the VU0 registers. For now I don't
check for overflow but I think it's going to become necessary in the
near future.

* The VUs are custom made SIMD processors used to accelerate
math operations on vectors and matrices. This doesn't seem that
bad but in reality they are probably the hardest piece of hardware
on the PS2 to emulate correctly. That is for two reasons:

1. Not much documentation
2. Complex and confusing pipeline

The first it pretty self explanatory. However the second reason,
the pipeline is what makes them so hard. Normally, even in LLE
emulators we don't care about the internal pipeline of the chips,
as it doesn't affect the result of the instructions themselves,
it just makes them run faster. The CPU doesn't expose its pipeline
to the target program.

Some architectures are different. MIPS for example has branch delay
slots which in reality are a pipeline quirk. Generally the more
pipeline quirks you expose to the program the more complex it is
to emulate correctly. The VUs basically expose their full pipeline...

For now we only support a portion of the macro mode instruction set.
The pipeline is going to come when the VU starts executing micro programs
and when I figure out how it works...