From 8c56039ca130dfef1f0bf204cc702eeb10801379 Mon Sep 17 00:00:00 2001
From: Ada Christine <adachristine18@gmail.com>
Date: Mon, 17 Jan 2022 12:23:44 +0000
Subject: task.h required for building

---
 kc/core/task.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 kc/core/task.c

(limited to 'kc/core/task.c')

diff --git a/kc/core/task.c b/kc/core/task.c
new file mode 100644
index 0000000..8f78516
--- /dev/null
+++ b/kc/core/task.c
@@ -0,0 +1,76 @@
+#include "task.h"
+#include "memory.h"
+#include "panic.h"
+#include "cpu.h"
+
+struct kc_thread *current_task = NULL;
+struct kc_thread *first_ready_task = NULL;
+struct kc_thread *last_ready_task = NULL;
+
+static int schedule_lock_cnt = 0;
+
+static void lock_scheduler(void);
+static void unlock_scheduler(void);
+static void set_thread_status(enum kc_thread_status status);
+static void idle_task_thread(void);
+
+extern uint64_t *get_tss_rsp0(void);
+
+void task_set_thread(struct kc_thread *task)
+{
+    // wrapper around cpu_set_thread
+    uint64_t *rsp0 = get_tss_rsp0();
+    cpu_set_thread(&current_task->state, &task->state, rsp0);
+}
+
+void task_schedule(void)
+{
+    if (first_ready_task)
+    {
+        struct kc_thread *task = first_ready_task;
+        first_ready_task = task->next;
+        task_set_thread(task);
+    }
+}
+
+static void lock_scheduler(void)
+{
+    __asm__ volatile ("cli;");
+    schedule_lock_cnt++;
+}
+
+static void unlock_scheduler(void)
+{
+    if (1 == schedule_lock_cnt)
+    {
+        schedule_lock_cnt--;
+        __asm__ volatile("sti;");
+    }
+}
+
+static void unblock_thread(struct kc_thread *thread)
+{
+    lock_scheduler();
+    if (!first_ready_task)
+    {
+        task_set_thread(thread);
+    }
+    else
+    {
+        first_ready_task->next = thread;
+        first_ready_task = thread;
+    }
+}
+
+static void set_thread_status(enum kc_thread_status status)
+{
+    lock_scheduler();
+    current_task->status = status;
+    task_schedule();
+    unlock_scheduler();
+}
+
+static void idle_task_thread(void)
+{
+}
+
-- 
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