90d73153fb
As pointed out in #11322 there is a hardware design issue in RISC-V that affects RV64 relocations. The problem is with how address bits are loaded into registers via lui / auipc and sign extension. If the hi20 relocation value happens to have its 32-bit sign bit set, i.e. value is 0x80000000 (but not negative! i.e. negative in 64-bit format) the relocation will fail, as the address is erroneously sign extended: 0x00000000_80000000 becomes 0xffffffff_80000000 which is not correct. Also, make sure the correct opcode is used with PCREL_HI20, it expects AUIPC (not LUI). The C compiler will never emit such code but when hand- writing assembly code this can happen. |
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| crypto | ||
| Documentation | ||
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| dummy | ||
| fs | ||
| graphics | ||
| include | ||
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| mm | ||
| net | ||
| openamp | ||
| pass1 | ||
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| syscall | ||
| tools | ||
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| wireless | ||
| .asf.yaml | ||
| .gitignore | ||
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| AUTHORS | ||
| CMakeLists.txt | ||
| CONTRIBUTING.md | ||
| INVIOLABLES.md | ||
| Kconfig | ||
| LICENSE | ||
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| 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.