Small additions and fixes in instructions

I added two instructions: cmp_r and nop.

cmp_r is simply register-to-register comparation.

nop is an instruction to explicitly do nothing. A sort of padding.

I also added a third default interrupt: “Math Error”. It is raised when division by zero is attempted.

Further changes

I changed a couple of things in the interrupt handling. I made sure when an interrupt is manually raised, the PC is incremented beforehand, so it won’t loop, and I made sure that calls to undefined interrupts aren’t actually executed but instantly return.

Next time?

Next time I’m doing (hopefully) a final pre-1.0 cleanup. I’ll be catching some possible crashes to make sure they’re CPU faults instead of emulator crashes and I’ll add a way to switch from Big to Little Endian to make sure everything is reachable in memory.

What’s below?

The screenshot below is my handleInterrupt() function.