Nim on Apache NuttX RTOS: Simple Nim for 32-bit RISC-V is OK. See https://github.com/apache/nuttx-apps/pull/2251

nuttx-nim-riscv32b.log

$ cat ../apps/examples/hello_nim/hello_nim_async.nim
proc hello_nim() {.exportc, cdecl.} =
  echo "Hello Nim!"
  GC_runOrc()

$ make
$ qemu-system-riscv32 \
  -M virt,aclint=on \
  -cpu rv32 \
  -smp 8 \
  -bios none \
  -kernel nuttx \
  -nographic

NuttShell (NSH) NuttX-12.0.3
nsh> uname -a
NuttX  12.0.3 bcc6374fb5d Jan  3 2024 02:22:42 risc-v rv-virt

nsh> hello_nim
Hello Nim!
nsh>