implement more accurate RTC
getMilliseconds() for node: return the actual value!!!
initial exception trigger support
basic interrupt, PIT support
add convenience function for SPSR
fix MRS/MSR to support SPSR
decode enough to vector from high 0xFFFF0000 down
support movs pc, lr for exception return
bail if AIC_DCR is written non-zero value
floor and ceil, useful to irqPoll every tick for now
update system timers to be more correct, fix validation
wrap imported functions for easier use
unwrap imported functions for readability
implement more of AIC and end of interrupt routine