From 95cd78840f0891e60f5ebecc8a8eb4fbaf3c2ebf Mon Sep 17 00:00:00 2001
From: Danny Holman <dholman@gymli.org>
Date: Sun, 12 Jan 2025 01:17:36 -0600
Subject: PROJECT RESTRUCTURING

Move the entire kernel into its own directory. Create new directories
for system commands, libraries and other required essentials for a
complete Unix-like operating system.

Signed-off-by: Danny Holman <dholman@gymli.org>
---
 kernel/core/sched.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 74 insertions(+)
 create mode 100644 kernel/core/sched.c

(limited to 'kernel/core/sched.c')

diff --git a/kernel/core/sched.c b/kernel/core/sched.c
new file mode 100644
index 0000000..b6096da
--- /dev/null
+++ b/kernel/core/sched.c
@@ -0,0 +1,74 @@
+#include <kernel/sched.h>
+#include <kernel/kthread.h>
+#include <kernel/panic.h>
+#include <libk/io.h>
+#include <libk/kmalloc.h>
+#include <libk/string.h>
+#include <stddef.h>
+
+static struct kthread *run_queue = NULL;
+static struct kthread *wait_queue = NULL;
+static struct kthread *cur = NULL;
+
+static int scheduler_enabled = 0;
+static struct kmutex scheduler_lock;
+
+void sched_init(void) {
+        disable_ints();
+        cur = kthread_create(NULL, NULL);
+        cur->stack = NULL;
+        switch_thread(cur, cur);
+        cur->state = THREAD_RUNNING;
+        scheduler_enabled = 1;
+        enable_ints();
+}
+
+void schedule_next(void) {
+        if (scheduler_enabled == 0)
+                return;
+        if (run_queue == NULL)
+                return;
+
+        struct kthread *thread = cur;
+        schedule_thread(cur);
+        cur = run_queue;
+        run_queue = run_queue->next;
+        cur->next = NULL;
+        cur->state = THREAD_RUNNING;
+        switch_thread(thread, cur);
+}
+
+void schedule_thread(struct kthread *thread) {
+        if (run_queue == NULL) {
+                run_queue = thread;
+                return;
+        }
+
+        kmutex_lock(&scheduler_lock);
+        struct kthread *temp = run_queue;
+        while (temp->next != NULL)
+                temp = temp->next;
+        temp->next = thread;
+        thread->state = THREAD_READY;
+        kmutex_unlock(&scheduler_lock);
+}
+
+void block_thread(struct kthread *thread) {
+        kmutex_lock(&scheduler_lock);
+        thread->next = wait_queue;
+        wait_queue = thread;
+        kmutex_unlock(&scheduler_lock);
+}
+
+void unblock_thread(struct kthread *thread) {
+        kmutex_lock(&scheduler_lock);
+        struct kthread *temp = wait_queue;
+        while (temp != NULL) {
+                if (temp->next == thread) {
+                        temp->next = thread->next;
+                        return;
+                }
+                temp = temp->next;
+        }
+        kmutex_unlock(&scheduler_lock);
+}
-- 
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