* Add an rp2040 specific #[entry] macro.
This macro extends the one from cortex-m-rt by code to unlock
all spinlocks on boot.
* Idiomatic pointer arithmetic
Apply suggestion by @9names, improving address calculations.
(This doesn't change the generated code at opt levels 2 or "z".)
Co-authored-by: 9names <60134748+9names@users.noreply.github.com>
* Created an itsy bitsy rp2040 board support package adapted from the bsp of the qt py rp2040. Special thanks to ithinuel for help in matrix
* Changed the board description so it doesn't match the qt py rp2040
* Changed blinky.rs to itsy_bitsy_blinky.rs and ran changes through cargo fmt
Bring in line with atsamd-hal GPIO v2
Copied as much as possible. Docs lifted mostly as-is.
Also add sample BSP for the Feather RP2040 in boards/feather_rp2040
May include a few random fixes from currently futile attempt to get doctests working.