Add set_interrupt_model_used method for calling \_PIC

[ChocolateLoverRaj]

Closes #356

Tested on QEMU q35 and Lenovo Ideapad Z560.

[martin-hughes]

Looks pretty reasonable from a first look. A couple of minor points, and one other thought:

• I think it would read better as just InterruptModel rather than InterruptModelUsed.

What do you think?

[ChocolateLoverRaj]

My only concern with naming it InterruptModel is that there is already an InterruptModel type.

[martin-hughes]

Any reason not to either add the values to the first three, or remove from the last three?

[ChocolateLoverRaj]

I left the first 3 to 0,1,2 implicitly, there's no reason not to add the values to them, I just felt lazy ig. The important thing is that 3 is left as Reserved.

[martin-hughes]

My only concern with naming it InterruptModel is that there is already an InterruptModel type.

Ah that does make sense! 😆 Thanks for the tweaks. In principle I'm happy, but I want to think a little more about the interrupt model types and names.

(Although I'm aware that we need to do a semver version bump in the future anyway, so we could adjust this later. I won't leave this hanging PR too long.)

[martin-hughes]

I guess InterruptModelUsed and InterruptModel as a pair are analogous to the pair ObjectType and Object. I didn't think of a better name for InterruptModelUsed, so I'll merge.