X-Git-Url: https://codewiz.org/gitweb?a=blobdiff_plain;f=bertos%2Fkern%2Fpreempt.c;h=4b5e66c3d2261b67874b645c79e0351f7e8d1805;hb=aea9c54dbb7ea4b957f675ffee7266e0432cfd42;hp=065faed88e17823eace2972fcd754927f0326f6e;hpb=d9d931610bca1df6ceb9227eacc9ff2c7f89b77a;p=bertos.git

diff --git a/bertos/kern/preempt.c b/bertos/kern/preempt.c
index 065faed8..4b5e66c3 100644
--- a/bertos/kern/preempt.c
+++ b/bertos/kern/preempt.c
@@ -102,14 +102,6 @@ CONFIG_DEPEND(CONFIG_KERN_PREEMPT, CONFIG_KERN);
 
 MOD_DEFINE(preempt)
 
-/**
- * CPU dependent context switching routines.
- *
- * Saving and restoring the context on the stack is done by a CPU-dependent
- * support routine which usually needs to be written in assembly.
- */
-EXTERN_C void asm_switch_context(cpu_stack_t **new_sp, cpu_stack_t **save_sp);
-
 /* Global preemption nesting counter */
 cpu_atomic_t preempt_count;
 
@@ -129,6 +121,7 @@ void preempt_yield(void);
 int preempt_needPreempt(void);
 void preempt_preempt(void);
 void preempt_switch(void);
+void preempt_wakeup(Process *proc);
 void preempt_init(void);
 
 /**
@@ -149,6 +142,8 @@ int preempt_needPreempt(void)
 		return 0;
 	if (!proc_preemptAllowed())
 		return 0;
+	if (LIST_EMPTY(&proc_ready_list))
+		return 0;
 	return _proc_quantum ? prio_next() > prio_curr() :
 			prio_next() >= prio_curr();
 }
@@ -179,11 +174,32 @@ void preempt_preempt(void)
 void preempt_switch(void)
 {
 	ASSERT(proc_preemptAllowed());
-	IRQ_ASSERT_ENABLED();
 
 	ATOMIC(preempt_schedule());
 }
 
+/**
+ * Immediately wakeup a process, dispatching it to the CPU.
+ */
+void preempt_wakeup(Process *proc)
+{
+	ASSERT(proc_preemptAllowed());
+	ASSERT(current_process);
+	IRQ_ASSERT_DISABLED();
+
+	if (prio_proc(proc) >= prio_curr())
+	{
+		Process *old_process = current_process;
+
+		SCHED_ENQUEUE(current_process);
+		_proc_quantum = CONFIG_KERN_QUANTUM;
+		current_process = proc;
+		proc_switchTo(current_process, old_process);
+	}
+	else
+		SCHED_ENQUEUE_HEAD(proc);
+}
+
 /**
  * Voluntarily release the CPU.
  */