I've now updated the Nested Interrupt Controller and ensured that the Processor Level is updated correctly.

The Processor Level now takes the Priority Level of the Interrupt plus 1. Also the Processor Level is now 5 bits rather than 4 bits so that the overflow stops any further Interrupts one a 0xF priority level interrupt has been hit.

Exceptions can still happen how but once the Processor Level hits 15 no more interrupts can be processed, the software has to deal with them to get the level down so it can accept more. The interrupts aren't lost just not acted upon.

Next to put the design back onto the server and see if it can be built again.

One thing I need to do is to update the Assembler so that the Vector table can take the labels as well. It will make things a lot easier.