This is required as we might be in interrupt context on this bare-metal target.

This allows the compiler to optimize better without loosing any performance / accuracy.

This leads to less jitter in the benchmark

This reduces interrupt load significantly.

This reduces interrupt load significantly.

The actual implementation is not atomic, as the value on the application layer would be limited.

This ensures we get absolutely accurate timing.

This call rarely needs to be truly atomic and the involved CPU overhead in making it atomic was unnecessary and introduces a lot of IRQ jitter with no value-add. The call has been moved to be non-atomic and the codebase will be inspected and changed in follow-up commits for the few instances where it is truly needed.

 - starts requirements for PX4 modules (hrt, param, etc)

 - can be reenabled after #11256 is merged

This avoids casting errors. An alternative to `std::round` would be to
add 0.5 before casting for positive values and subtract 0.5 before
casting for negative values.

    - matrix in PX4/Firmware (31bd46d2ed700b2da9fc314e9b87d9b683a66606): https://github.com/PX4/Matrix/commit/18fba8221cc1840964c43f04d8c2aa21857e1b9b
    - matrix current upstream: https://github.com/PX4/Matrix/commit/6b0777d815cd64902eb0575d56ec52f53aebb4a0
    - Changes: https://github.com/PX4/Matrix/compare/18fba8221cc1840964c43f04d8c2aa21857e1b9b...6b0777d815cd64902eb0575d56ec52f53aebb4a0

    6b0777d 2019-01-21 Daniel Agar - stdlib_imports cinttypes currently unavailable in NuttX toolchain (#79)

 - <limits> isn't available in the NuttX c++ standard library

 - <limits> isn't available in the NuttX c++ standard library

    - mavlink v2.0 in PX4/Firmware (ee517afb7c8b34e88daf656834a3315be72a4f40): https://github.com/mavlink/c_library_v2/commit/339abb5f4c20865ea67dd417b099e3f54683a2ad
    - mavlink v2.0 current upstream: https://github.com/mavlink/c_library_v2/commit/e302e1b735e47e9d33c3bad579dd7c6c089c1bb3
    - Changes: https://github.com/mavlink/c_library_v2/compare/339abb5f4c20865ea67dd417b099e3f54683a2ad...e302e1b735e47e9d33c3bad579dd7c6c089c1bb3

 - add -a option to display all possible system parameters

matrix::Quatf() calls sinf(), which caused a valgrind warning

There were accidents because when missions lead through an obstacle
and it should be avoided but the setpoints from the external obstacle
avoidance module are suddenly missing the mission is continued into the
obstacle which results in a crash.