ARM Architecture Reference Manual says: "Setting SYST_RVR to zero has the effect of disabling the SysTick counter independently of the counter enable bit."
If Monotonic's ratio is less than one, the timeout calculations
can compute zero if next task is scheduled after current instant, but
before next timer tick. This results in disabling SYST and freezing the
timer queue.
This commit:
- Implements RFC 147: "all functions must be safe"
- Implements RFC 155: "explicit Context parameter"
- Implements the pending breaking change #141: reject assign syntax in `init`
(which was used to initialize late resources)
- Refactors code generation to make it more readable -- there are no more random
identifiers in the output -- and align it with the book description of RTFM
internals.
- Makes the framework hard depend on `core::mem::MaybeUninit` and thus will
require nightly until that API is stabilized.
- Fixes a ceiling analysis bug where the priority of the system timer was not
considered in the analysis.
- Shrinks the size of all the internal queues by turning `AtomicUsize` indices
into `AtomicU8`s.
- Removes the integration with `owned_singleton`.
