Implement thrd_yield on linux

include/threads.h

@@ -18,4 +18,5 @@ enum {
 
 int thrd_create(thrd_t *thr, thrd_start_t func, void *arg);
 int thrd_join(thrd_t thr, int *out_exit_code);
-int thrd_detach(thrd_t thr);
+int thrd_detach(thrd_t thr);
+void thrd_yield();

include/tinyrt.h

@@ -58,6 +58,7 @@ static _RT_Status _rt_thread_create(_RT_Thread *thread, int (*thread_fn)(void *c
 static _RT_Status _rt_thread_join(_RT_Thread *thread, int *out_exit_code);
 static _RT_Status _rt_thread_detach(_RT_Thread *thread);
 static _RT_Status _rt_thread_terminate(_RT_Thread *thread);
+static _RT_Status _rt_thread_yield();
 static _RT_Status _rt_thread_sleep(u64 time);
 static _RT_Status _rt_thread_get_timer_freq(u64 *freq);
 

os/linux/tinyrt-threads.c

@@ -96,6 +96,15 @@ static _RT_Status _rt_thread_detach(_RT_Thread *thread) {
     return _RT_STATUS_OK;
 }
 
+static _RT_Status _rt_thread_yield() {
+    i64 status = syscall(SYS_sched_yield);
+    if(status != 0) {
+        // shouldn't happen on linux
+        return _RT_ERROR_GENERIC;
+    }
+    return _RT_STATUS_OK;
+}
+
 static _RT_Status _rt_thread_terminate(_RT_Thread *thread) {
     return _RT_ERROR_NOT_IMPLEMENTED;
 }

src/cia-sync/mutex.c

@@ -18,6 +18,7 @@ void cia_mutex_lock(Cia_Mutex *mutex) {
             , memory_order_acquire
             , memory_order_relaxed
         );
+        
         // We got the mutex, lets bail
         if(p_tag == _CIA_MUTEX_FREE) {
             break;

src/stdlib-thread/thread.c

@@ -22,3 +22,7 @@ int thrd_join(thrd_t thr, int *out_exit_code) {
     }
     return thrd_error;
 }
+
+void thrd_yield(void) {
+    _rt_thread_yield();
+}