A small but fully functional kernel of a multithreaded operating system with time sharing, written for RISC V architecture using assembly and C/C++. Includes a memory allocator, threads, semaphores and preemption on timer and keyboard interrupts. The user application and the kernel use the same address space, as together they make a static program in the operating memory. The kernel was developed in a virtual machine based on Linux. These are the implemeneted system calls (C layer):
- void* mem_alloc (size_t size)
- int mem_free (void*)
- int thread_create (thread_t* handle, void(start-routine)(void), void* arg)
- int thread_exit ()
- void thread_dispatch ()
- void thread_join ( thread_t handle)
- int sem_open (sem_t* handle, unsigned init)
- int sem_close (sem_t handle)
- int sem_wait (sem_t id)
- int sem_signal (sem_t id)
- int time_sleep (time_t)
- char getc ()
- void putc (char)
The C++ interface is given in the file syscall_cpp.hpp.
The user application should be written in function void userMain().
The files in the tests folder are not written by me and were used for testing and evaluating the features.
The full text of the project requierements and explanations in Serbian is given in the file Projektni zadatak 2023.