A minimal RTOS for Raspberry Pi written in C and ARM assembly.

Runs tasks with basic context switching. Built for learning and fun.

• Bare-metal kernel that runs on qemu (to be tested on hardware)
• Basic cross-platform architecture: ARCHITECTURE.md
• Basic scheduling, context switching

make

For now the user can modify user/main.c to run their code.

Example snippet:

#include "smvrt.h"

int count = 0;

void producer() {
  if (count < 2) {
    smvrt_print("producing...\n");
    for (volatile int i = 0; i < 100000; i++)
      ;
    count++;
  }
}

void consumer() {
  if (count > 0) {
    smvrt_print("consuming...\n");
    for (volatile int i = 0; i < 100000000; i++)
      ;
    count--;
  }
}

void main() {
  smvrt_scheduler_add(producer);
  smvrt_scheduler_add(consumer);
  smvrt_scheduler_run();
}

Currently, the Makefile doesn't have any customization. This is a TODO.

1. Copy smvrt.img onto your SD card's boot partition.
2. Boot into your Raspberry Pi.
   Note: Currently, code has only been tested in a hypervisor.

sudo pacman -S qemu-arch-extra # if not installed
make                           # build smvrt.img
make run

Currently, the interface is only tested on a hypervisor.