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Keith Packard d0c75f3b96 lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21]
Picolibc is a fork of newlib designed and tested on embedded systems. It
offers a smaller memory footprint (both ROM and RAM), and native TLS
support, which uses the Zephyr TLS support.

By default, the full printf version is included in the executable, which
includes exact floating point and long long input and output. A
configuration option has been added to switch to the integer-only
version (which also omits long long support).

Here are some size comparisons using qemu-cortex-m3 and this application
(parameters passed to printf to avoid GCC optimizing it into puts):

void main(void)
{
    printf("Hello World! %s %d\n", CONFIG_BOARD, 12);
}

                       FLASH    SRAM
    minimal             8696    3952
    picolibc int        7600    3960
    picolibc float     12304    3960
    newlib-nano int    11696    4128
    newlib-nano float  30516    4496
    newlib             34800    6112

---

v2:
	Include picolibc-tls.ld

v3:
	Document usage in guides/c_library.rst and
	getting_started/toolchain_other_x_compilers.rst

v4:
	Lost the lib/libc/picolibc directory somehow!

v5:
	Add PICOLIBC_ALIGNED_HEAP_SIZE configuration option.
	Delete PICOLIBC_SEMIHOST option support code

v6:
	Don't allocate static RAM for TLS values; TLS
	values only need to be allocated for each thread.

v7:
	Use arm coprocessor for TLS pointer storage where supported for
	compatibility with the -mtp=cp15 compiler option (or when the
	target cpu type selects this option)

	Add a bunch of tests

	Round TLS segment up to stack alignment so that overall stack
	remains correctly aligned

	Add aarch64 support

	Rebase to upstream head

v8:
	Share NEWLIB, NEWLIB_NANO and PICOLIBC library configuration
	variables in a single LIBC_PARTITIONS variable instead of
	having separate PICOLIBC_PART and NEWLIB_PART variables.

v9:
	Update docs to reference pending sdk-ng support for picolibc

v10:
	Support memory protection by creating a partition for
	picolibc shared data and any pre-defined picolibc heap.

v11:
	Fix formatting in arch/arm/core/aarch64/switch.S

v12:
	Remove TLS support from this patch now that TLS is upstream
	Require THREAD_LOCAL_STORAGE when using PICOLIBC for architectures
	that support it.

v13:
	Merge errno changes as they're only needed for picolibc.
	Adapt cmake changes suggested by Torsten Tejlmand Rasmussen

v14:
	Update to picolibc 1.7 and newer (new stdin/stdout/stderr ABI)

v15:
	Respond to comments from dcpleung:
	* switch kernel/errno to use CONFIG_LIBC_ERRNO instead of
          CONFIG_PICOLIBC
	* Add comment to test/lib/sprintf as to why the %n test
	  was disabled for picolibc.

v16:
	Switch picolibc to a module built with Zephyr. This eliminates
	toolchain dependencies and allows compiler settings for Zephyr
	to also be applied to picolibc.

v17:
	Provide Zephyr-specific 'abort' implementation.
	Support systems with MMU

v18:
	Allow use of toolchain picolibc version.

v19:
	Use zephyr/ for zephyr headers

v20:
	Add locking
	Use explicit commit for picolibc module

v21:
	Create PICOLIBC_SUPPORTED config param. Set on arc, arm, arm64,
	mips and riscv architectures.

Signed-off-by: Keith Packard <keithp@keithp.com>
2022-06-22 13:15:55 +02:00
.github ci: assigner: Skip assignment for draft pull requests 2022-06-09 22:19:06 +09:00
arch riscv: Rename __irq_wrapper to _isr_wrapper 2022-06-21 20:27:20 -04:00
boards lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21] 2022-06-22 13:15:55 +02:00
cmake cmake/clang: Disable -Wunused-but-set-variable warnings 2022-06-14 01:50:36 +09:00
doc doc/guides/device_mgmt/smp: Extend reset command with force option 2022-06-21 11:55:19 +02:00
drivers drivers: sensor: fxos8700: Update driver to use gpio_dt_spec 2022-06-22 12:27:17 +02:00
dts dts: stm32u5: correct can1 clocks property 2022-06-22 12:29:03 +02:00
include/zephyr lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21] 2022-06-22 13:15:55 +02:00
kernel kernel: Migrate to K_KERNEL_PINNED_STACK_ARRAY_DECLARE 2022-06-20 10:25:52 +02:00
lib lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21] 2022-06-22 13:15:55 +02:00
misc misc: generated: update configs.c template with <zephyr/...> prefix 2022-05-09 12:45:29 -04:00
modules soc: arm: gigadevice: use common API headers 2022-06-22 18:41:19 +09:00
samples samples/subsys/audio/sof: fix sys-ticks-per-sec to 15000 2022-06-22 12:28:48 +02:00
scripts west: Fix --openocd-search argument 2022-06-20 10:26:23 +02:00
share cmake: support QUIET argument for find_package 2022-06-14 22:28:18 +02:00
soc soc: esp32: opt to make device handles in dram 2022-06-22 12:27:43 +02:00
submanifests west.yml: allow users to easily add more modules 2021-10-07 13:45:42 +02:00
subsys Bluetooth: Host: Fix ATT security vulnerabilities 2022-06-22 12:29:26 +02:00
tests pm: Introduce CONFIG_PM_DEVICE_RUNTIME_EXCLUSIVE 2022-06-22 12:24:43 +02:00
.checkpatch.conf checkpatch: Ignore IS_ENABLED_CONFIG warnings 2021-10-18 08:28:01 -04:00
.clang-format clang-format: simplify by inheriting from LLVM 2022-06-15 09:37:30 -04:00
.codecov.yml
.editorconfig editorconfig: Improve verbosity 2022-04-28 08:55:39 -04:00
.gitattributes gitattributes: consider SVG files generated 2021-10-14 12:42:44 -04:00
.gitignore gitignore: Ignore emacs temporary edit files 2022-05-20 18:21:18 +02:00
.gitlint gitlint: Stop ignoring merge, revert, fixup and squash commits 2022-01-10 08:13:36 -05:00
.mailmap mailmap: update mailmap file with some stray emails 2021-06-17 14:15:41 -04:00
CMakeLists.txt lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21] 2022-06-22 13:15:55 +02:00
CODE_OF_CONDUCT.md coc: move to markdown format 2019-01-24 15:37:15 -05:00
CODEOWNERS MAINTAINERS: remove s1000 references 2022-06-13 16:19:51 -04:00
CONTRIBUTING.rst doc: Fixed a link in CONTRIBUTING.rst 2019-02-28 12:46:04 -08:00
Kconfig kconfig: Clean up header comments and make them consistent 2019-11-04 17:31:27 -05:00
Kconfig.zephyr build: make Zephyr stdint convention enforcing configurable 2022-06-22 12:26:46 +02:00
LICENSE
MAINTAINERS.yml MAINTAINERS: Add Laird Connectivity platform 2022-06-20 14:16:13 -04:00
README.rst readme: Update stale documentation links 2022-06-06 12:07:12 +02:00
VERSION version: Fix the EXTRAVERSION field 2022-06-05 20:11:17 +02:00
version.h.in cmake: version.h generation performed at build time 2022-02-08 07:50:24 -05:00
west.yml lib/libc: Add picolibc support (aarch32, aarch64 and RISC-V) [v21] 2022-06-22 13:15:55 +02:00
zephyr-env.cmd scripts: remove west from scripts/ 2019-01-29 10:15:01 +01:00
zephyr-env.sh everywhere: fix typos 2022-03-18 13:24:08 -04:00

.. raw:: html

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     <p align="center">
       <img src="doc/_static/images/logo-readme.svg">
     </p>
   </a>

   <a href="https://bestpractices.coreinfrastructure.org/projects/74"><img
   src="https://bestpractices.coreinfrastructure.org/projects/74/badge"></a>
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The Zephyr Project is a scalable real-time operating system (RTOS) supporting
multiple hardware architectures, optimized for resource constrained devices,
and built with security in mind.

The Zephyr OS is based on a small-footprint kernel designed for use on
resource-constrained systems: from simple embedded environmental sensors and
LED wearables to sophisticated smart watches and IoT wireless gateways.

The Zephyr kernel supports multiple architectures, including ARM (Cortex-A,
Cortex-R, Cortex-M), Intel x86, ARC, Nios II, Tensilica Xtensa, and RISC-V,
SPARC, MIPS, and a large number of `supported boards`_.

.. below included in doc/introduction/introduction.rst


Getting Started
***************

Welcome to Zephyr! See the `Introduction to Zephyr`_ for a high-level overview,
and the documentation's `Getting Started Guide`_ to start developing.

.. start_include_here

Community Support
*****************

Community support is provided via mailing lists and Discord; see the Resources
below for details.

.. _project-resources:

Resources
*********

Here's a quick summary of resources to help you find your way around:

* **Help**: `Asking for Help Tips`_
* **Documentation**: http://docs.zephyrproject.org (`Getting Started Guide`_)
* **Source Code**: https://github.com/zephyrproject-rtos/zephyr is the main
  repository; https://elixir.bootlin.com/zephyr/latest/source contains a
  searchable index
* **Releases**: https://github.com/zephyrproject-rtos/zephyr/releases
* **Samples and example code**: see `Sample and Demo Code Examples`_
* **Mailing Lists**: users@lists.zephyrproject.org and
  devel@lists.zephyrproject.org are the main user and developer mailing lists,
  respectively. You can join the developer's list and search its archives at
  `Zephyr Development mailing list`_. The other `Zephyr mailing list
  subgroups`_ have their own archives and sign-up pages.
* **Nightly CI Build Status**: https://lists.zephyrproject.org/g/builds
  The builds@lists.zephyrproject.org mailing list archives the CI nightly build results.
* **Chat**: Real-time chat happens in Zephyr's Discord Server. Use
  this `Discord Invite`_ to register.
* **Contributing**: see the `Contribution Guide`_
* **Wiki**: `Zephyr GitHub wiki`_
* **Issues**: https://github.com/zephyrproject-rtos/zephyr/issues
* **Security Issues**: Email vulnerabilities@zephyrproject.org to report
  security issues; also see our `Security`_ documentation. Security issues are
  tracked separately at https://zephyrprojectsec.atlassian.net.
* **Zephyr Project Website**: https://zephyrproject.org

.. _Discord Invite: https://chat.zephyrproject.org
.. _supported boards: http://docs.zephyrproject.org/latest/boards/index.html
.. _Zephyr Documentation: http://docs.zephyrproject.org
.. _Introduction to Zephyr: http://docs.zephyrproject.org/latest/introduction/index.html
.. _Getting Started Guide: http://docs.zephyrproject.org/latest/develop/getting_started/index.html
.. _Contribution Guide: http://docs.zephyrproject.org/latest/contribute/index.html
.. _Zephyr GitHub wiki: https://github.com/zephyrproject-rtos/zephyr/wiki
.. _Zephyr Development mailing list: https://lists.zephyrproject.org/g/devel
.. _Zephyr mailing list subgroups: https://lists.zephyrproject.org/g/main/subgroups
.. _Sample and Demo Code Examples: http://docs.zephyrproject.org/latest/samples/index.html
.. _Security: http://docs.zephyrproject.org/latest/security/index.html
.. _Asking for Help Tips: https://docs.zephyrproject.org/latest/develop/getting_started/index.html#asking-for-help