[tyndur-devel] [PATCH 4/8] kernel2: pm_scheduler_try_switch()

[Kevin Wolf <kevin@xxxxxxxxxx>]

+ kernel2: pm_scheduler_try_switch() wechselt zu einem gegebenen Thread,
  wenn dieser lauffähig ist.

Signed-off-by: Kevin Wolf <kevin@xxxxxxxxxx>
---
 src/kernel2/include/tasks.h       |    3 +++
 src/kernel2/src/tasks/scheduler.c |   20 ++++++++++++++++++++
 2 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/src/kernel2/include/tasks.h b/src/kernel2/include/tasks.h
index 382a362..fc0bc88 100644
--- a/src/kernel2/include/tasks.h
+++ b/src/kernel2/include/tasks.h
@@ -205,6 +205,9 @@ void pm_scheduler_push(pm_thread_t* thread);
 /// Kontrolle vom aktuellen Kernelthread an einen anderen Thread abgeben
 void pm_scheduler_yield(void);
 
+/// Versucht einen Taskwechsel zum übergebenen Thread
+void pm_scheduler_try_switch(pm_thread_t* thread);
+
 /**
  * Initialisierung
  */
diff --git a/src/kernel2/src/tasks/scheduler.c b/src/kernel2/src/tasks/scheduler.c
index bf282c2..43c8180 100644
--- a/src/kernel2/src/tasks/scheduler.c
+++ b/src/kernel2/src/tasks/scheduler.c
@@ -233,3 +233,23 @@ void pm_scheduler_yield(void)
     asm volatile("int $0x30;" : : "a" (SYSCALL_PM_SLEEP));
 }
 
+/**
+ * Macht den übergebenen Thread zum aktuellen Thread dieser CPU, wenn er
+ * momentan lauffähig ist. Wenn nicht, bleibt der bisherige Thread aktiv.
+ */
+void pm_scheduler_try_switch(pm_thread_t* thread)
+{
+    cpu_t* cpu;
+
+    if (thread->status != PM_STATUS_READY) {
+        return;
+    }
+
+    cpu = cpu_get_current();
+    if (cpu->thread != thread) {
+        pm_scheduler_push(cpu->thread);
+        pm_scheduler_get(thread);
+        thread->status = PM_STATUS_RUNNING;
+        cpu->thread = thread;
+    }
+}
-- 
1.6.0.2