25876e327e
For AVR, atomic functions generated by LOAD macro turn into load surrounded by up_irq_save and up_irq_restore. The generated code was incorrect as can be seen from disassembly of __atomic_load_4: in r18, 0x3f ; store interrupts enabled flag cli ; disable interrupts out 0x3f, r18 ; restore the flag movw r30, r24 ; copy parameter (address) to pointer register ld r22, Z ; indirect load to return value registers ldd r23, Z+1 ldd r24, Z+2 ldd r25, Z+3 ret ; return The interrupts are disabled to be immediately re-enabled, the load only takes place after that. Both up_irq_save and up_irq_restore are defined in inline assembly. Other architectures (x86/486, Risc-V) mark this assembly with clobbers: memory. Doing the same thing for AVR alleviates the problem: in r18, 0x3f ; store interrupts enabled flag cli ; disable interrupts movw r30, r24 ; copy address ld r22, Z ; load ldd r23, Z+1 ldd r24, Z+2 ldd r25, Z+3 out 0x3f, r18 ; restore interrupts enabled flag ret ; return Besides compiling the code and checking the assembly, this was tested with a custom stress application on AVR128DA28. Assembly of up_irq_enable is marked in the same way with regards to clobbers. This patch also removes two functions that are not called from anywhere (up_irq_disabled, putsreg) Signed-off-by: Kerogit <kr.git@kerogit.eu> |
||
|---|---|---|
| .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 | ||
| .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.