Changes since 6.5 includes
* Upgraded simulator to MIPS32, Version 1 architecture (except details of
FPU and memory).
* Exceptions and interrupts reimplemented, to make them closer to the
actual hardware.
* Memory mapped IO console reimplemented to make it work properly.
* Implemented timer in CPU.
* Improved implementation of delayed load instructions.
as well as many minor changes.
Fixes PR pkg/30227 reported from Michai Ramakers.
