ptos: sched: Add thread enqueue/dequeue helpers

Signed-off-by: Chloe M <chloe@mensia.org>

service/ptos/ke/sched.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2026, Chloe M.
+ * Provided under the BSD-3 clause.
+ *
+ * Description: Scheduler management
+ * Author:      Chloe M.
+ */
+
+#include <ke/sched.h>
+
+VOID
+KeSchedEnqueue(SCHED_QUEUE *Queue, THREAD *Thread)
+{
+    if (Queue == NULL || Thread == NULL) {
+        return;
+    }
+
+    KeSpinLockAcquire(&Queue->Lock, true);
+    TAILQ_INSERT_TAIL(&Queue->ThreadQueue, Thread, ThreadLink);
+    KeSpinLockRelease(&Queue->Lock);
+}
+
+THREAD *
+KeSchedDequeue(SCHED_QUEUE *Queue)
+{
+    THREAD *Thread;
+
+    KeSpinLockAcquire(&Queue->Lock, true);
+    if (TAILQ_EMPTY(&Queue->ThreadQueue)) {
+        KeSpinLockRelease(&Queue->Lock);
+        return NULL;
+    }
+
+    Thread = TAILQ_FIRST(&Queue->ThreadQueue);
+    TAILQ_REMOVE(&Queue->ThreadQueue, Thread, ThreadLink);
+    KeSpinLockRelease(&Queue->Lock);
+    return Thread;
+}