Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
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hanzhijian 87d84e437a libc/crc32: add IEEE-compatible crc32_ieee for Linux/zlib interop
Add crc32_ieee() and crc32_ieeepart() that produce CRC32 values
compatible with Linux/zlib. The difference from the existing crc32():

  crc32():        init=0, no final XOR (NuttX native)
  crc32_ieee():   init=0xFFFFFFFF, final XOR 0xFFFFFFFF (Linux/zlib)

The existing crc32() and crc32part() are unchanged to avoid breaking
existing callers (bbsram, sbram, etc.).

New functions:
  crc32_ieee(src, len)              - full CRC, Linux-compatible
  crc32_ieeepart(src, len, crcval)  - incremental CRC, Linux-compatible

Verified on sim:nsh against known Linux zlib test vectors:
  crc32_ieee("hello")     = 0x3610a686 (Linux: 0x3610a686) PASS
  crc32_ieee("123456789") = 0xcbf43926 (Linux: 0xcbf43926) PASS
  crc32_ieee("")           = 0x00000000 (Linux: 0x00000000) PASS
  crc32_ieeepart incremental  = 0xcbf43926               PASS
  crc32("hello")          = 0xf032519b (unchanged)       PASS

Signed-off-by: hanzhijian <hanzhijian@zepp.com>
2026-07-03 10:18:28 +08:00
.github build(deps): bump actions/cache from 5 to 6 2026-06-29 12:59:18 +02:00
arch drivers: Fix comment typos — 'Pubic' → 'Public' across drivers and headers. 2026-07-02 13:29:48 +08:00
audio include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
binfmt fs/binfmt: Enforce POSIX execute permissions prior to binary load 2026-06-13 21:07:01 +08:00
boards stm32f746g-disco: Add support for Winbond W25Q128JVEQ flash chip 2026-07-02 09:36:23 +02:00
cmake build/fix: remove nonexistent target in cmake 2026-06-08 16:03:21 +08:00
crypto !nuttx: drop redundant casts on tv_sec/tv_nsec and fix printf formats 2026-05-19 16:21:28 +08:00
Documentation Documentation/spresense: rewrite board page with images and configs 2026-07-02 09:02:54 -03:00
drivers drivers/contactless/mfrc522: Contactless Driver Is Not Robust 2026-07-02 09:38:49 +02:00
dummy
fs !include/fcntl.h: align open flags with Linux values 2026-06-30 13:43:44 +08:00
graphics !include/fcntl.h: align open flags with Linux values 2026-06-30 13:43:44 +08:00
include libc/crc32: add IEEE-compatible crc32_ieee for Linux/zlib interop 2026-07-03 10:18:28 +08:00
libs libc/crc32: add IEEE-compatible crc32_ieee for Linux/zlib interop 2026-07-03 10:18:28 +08:00
mm mm/gran: reject pools with too many granules 2026-06-24 08:41:28 -03:00
net !include/fcntl.h: align open flags with Linux values 2026-06-30 13:43:44 +08:00
openamp openamp: fix CMake dcache option 2026-05-10 15:03:24 +02:00
pass1 Makefile: Remove make depend files by make distclean 2026-02-16 16:27:57 +01:00
sched !include/fcntl.h: align open flags with Linux values 2026-06-30 13:43:44 +08:00
syscall syscall: fcntl param3 type to uintptr_t 2026-04-27 12:01:55 -03:00
tools arch/arm: add Realtek RTL8721Dx and RTL8720F (Ameba WHC) support 2026-07-01 09:18:06 -03:00
video video: ensure video library is non-empty 2026-05-08 19:51:39 +08:00
wireless include/debug.h: Move to include/nuttx/debug.h 2026-04-07 07:50:06 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines !boards: Remove NSH_ARCHINIT and board_app_initialize 2026-05-02 18:36:46 +08:00
.codespellrc arch/sim: replace macOS C++ constructor runtime hack with post-link patch 2026-05-19 07:08:55 -03:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake/nuttx_toolchain.cmake: track preprocessed include deps 2026-06-04 17:22:43 +08:00
CONTRIBUTING.md docs: Fix typos, formatting, and numbering in README.md and CONTRIBUTING.md. 2026-03-23 12:05:24 +01:00
INVIOLABLES.md
Kconfig sched/misc/assert: Add CONFIG_SCHED_DUMP_TASKS and CONFIG_SCHED_DUMP_STACK 2026-06-09 08:04:54 -04:00
LICENSE !arch/stm32: move stm32l1 and finalize the directory split 2026-06-24 14:54:44 -03:00
Makefile tools: migrate to SPDX identifier 2024-09-10 23:11:11 +08:00
NOTICE
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

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Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

Getting Started

First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.

Documentation

You can find the current NuttX documentation on the Documentation Page.

Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.

The old NuttX documentation is still available in the Apache wiki.

Supported Boards

NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.

Contributing

If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.

License

The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.