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An FDPIC module is compiled by the stock arm-none-eabi GCC, which emits correct FDPIC objects for both C and C++, but it cannot be assembled or linked by that toolchain: its as rejects the FDPIC relocations, and its ld carries the armelf emulation alone. Linking FDPIC objects with the stock ld does not fail, which is the awkward part. It produces an object marked "UNIX - System V" instead of "ARM FDPIC" and turns every import into an R_ARM_JUMP_SLOT where the ABI wants an R_ARM_FUNCDESC_VALUE. A jump slot is one word and a descriptor is two, a code address and the GOT that goes with it, so the module links cleanly and then calls out of itself with the caller's data base still in the PIC register. No distribution packages the arm-uclinuxfdpiceabi target, so the image builds it, the way the Renesas stage already builds its own binutils. Only binutils is needed, no GCC and no C library, so the stage takes about a minute and the install is 20 MB stripped. The tarball comes from sourceware.org, the binutils project's own host, because ftp.gnu.org is not reliably reachable from every builder. curl runs with --fail so that a bad fetch says so, rather than piping an error page into tar and failing as "File format not recognized". Signed-off-by: Marco Casaroli <marco.casaroli@gmail.com> |
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| .github | ||
| arch | ||
| audio | ||
| binfmt | ||
| boards | ||
| cmake | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| dummy | ||
| fs | ||
| graphics | ||
| include | ||
| libs | ||
| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
| sched | ||
| syscall | ||
| tools | ||
| video | ||
| wireless | ||
| .asf.yaml | ||
| .codespell-ignore-lines | ||
| .codespellrc | ||
| .editorconfig | ||
| .gitignore | ||
| .gitmessage | ||
| .pre-commit-config.yaml | ||
| .yamllint | ||
| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
| Makefile | ||
| NOTICE | ||
| README.md | ||
| ReleaseNotes | ||
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.