Hi Matheus, it seems you are using an Arm processor that does not implement the atomic instructions LDREX and STREX. This is the case for Arm Cortex-M0/M0+ line, which is based on the arm-v6m ISA. In this case, you'd need to implement these functions by providing the atomicity requirements with support from the OS. Currently the ESP32-C3 chip provides this implementation, but it could be made generic with by some work to the build system. There is an open issue for this improvement: https://github.com/apache/incubator-nuttx/issues/3483
Best regards, Gustavo. On Mon, May 31, 2021 at 7:53 AM Matheus Castello <math...@castello.eng.br> wrote: > > Trying to use libcxx for port a project to Nuttx and I'm having the > following errors: > > ``` > LD: nuttx > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(locale.o): in function > `std::__1::locale::id::__init()': > locale.cpp:(.text+0x1890): undefined reference to `__atomic_fetch_add_4' > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(memory.o): in function > `std::__1::__shared_count::__add_shared()': > memory.cpp:(.text+0x60): undefined reference to `__atomic_fetch_add_4' > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(memory.o): in function > `std::__1::__shared_count::__release_shared()': > memory.cpp:(.text+0x72): undefined reference to `__atomic_fetch_add_4' > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(memory.o): in function > `std::__1::__shared_weak_count::__add_weak()': > memory.cpp:(.text+0x9a): undefined reference to `__atomic_fetch_add_4' > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(memory.o): in function > `std::__1::__shared_weak_count::__release_weak()': > memory.cpp:(.text+0xc0): undefined reference to `__atomic_fetch_add_4' > arm-none-eabi-ld: > /home/castello/projects/N/nuttx/staging/libxx.a(memory.o): in function > `std::__1::__shared_weak_count::lock()': > memory.cpp:(.text+0x102): undefined reference to > `__atomic_compare_exchange_4' > ``` > > I can already build it using the simulator but with arm-none-eabi I'm > not having success. If anyone has any hints or light on what I'm doing > wrong, I'll be very grateful :) > > BR, > Matheus Castello -- Gustavo Henrique Nihei
