From e15d41a5619c41f3440369e625d6d96921718221 Mon Sep 17 00:00:00 2001
From: Christian Cunningham <cc@localhost>
Date: Thu, 30 Dec 2021 20:50:44 -0800
Subject: Added Data Structures

Added basic scheduling

TODO: Preserve registers for context switch
---
 src/sys/core.c     |  3 ++
 src/sys/schedule.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/sys/schedule.h | 29 +++++++++++++++++++
 3 files changed, 113 insertions(+)
 create mode 100644 src/sys/schedule.c
 create mode 100644 src/sys/schedule.h

(limited to 'src/sys')

diff --git a/src/sys/core.c b/src/sys/core.c
index f75ec35..ebf50a0 100644
--- a/src/sys/core.c
+++ b/src/sys/core.c
@@ -2,10 +2,13 @@
 #include "../drivers/uart.h"
 #include "../graphics/drawer.h"
 #include "../graphics/lfb.h"
+#include "../lib/ll.h"
 #include "../lib/mem.h"
+#include "../lib/q.h"
 #include "../lib/strings.h"
 #include "../sys/core.h"
 #include "../sys/power.h"
+#include "../sys/schedule.h"
 #include "../sys/timer.h"
 #include "../util/mutex.h"
 #include "../util/time.h"
diff --git a/src/sys/schedule.c b/src/sys/schedule.c
new file mode 100644
index 0000000..f920b0e
--- /dev/null
+++ b/src/sys/schedule.c
@@ -0,0 +1,81 @@
+#include "../sys/schedule.h"
+#include "../lib/ll.h"
+#include "../lib/q.h"
+
+#ifdef FLAT
+static struct Task* task_list[256];
+
+static struct Scheduler scheduler = {
+	.tasks = task_list,
+};
+
+static unsigned int ntask_i = 0;
+
+void add_task(struct Task* t)
+{
+	scheduler.tasks[ntask_i] = t;
+	ntask_i += 1;
+	if (ntask_i > 256) {
+		ntask_i = 0;
+	}
+}
+
+unsigned int get_task_length(void)
+{
+	return ntask_i;
+}
+
+void execute_task(void)
+{
+	if (scheduler.tasks[ntask_i-1] != 0)
+		scheduler.tasks[ntask_i-1]->task();
+}
+#elseif LL
+static struct LL bl = {
+	.prev = 0,
+	.next = 0,
+};
+static struct Scheduler scheduler = {
+	.tasks = &bl,
+};
+#else
+static struct Q_base bq = {
+	.next = 0,
+	.last = 0,
+};
+static struct Scheduler  scheduler = {
+	.tasks = &bq,
+};
+
+void add_task(struct Task* t)
+{
+	pushq(scheduler.tasks, t);
+}
+
+unsigned int get_task_length(void)
+{
+	unsigned int length = 0;
+	if (scheduler.tasks->last == 0)
+		return length;
+	else if (scheduler.tasks->next == scheduler.tasks->last)
+		return 1;
+	else {
+		struct Q* q = scheduler.tasks->next;
+		length += 1;
+		while (q->next != 0) {
+			q = q->next;
+			length += 1;
+		}
+		return length;
+	}
+}
+
+void execute_task(void)
+{
+	if (scheduler.tasks->last != 0) {
+		struct Task* tsk = (struct Task*)scheduler.tasks->next->data;
+		(tsk->task)();
+		popq(scheduler.tasks);
+	}
+}
+#endif
diff --git a/src/sys/schedule.h b/src/sys/schedule.h
new file mode 100644
index 0000000..04dad6a
--- /dev/null
+++ b/src/sys/schedule.h
@@ -0,0 +1,29 @@
+#ifndef SYS_SCHEDULE_H
+#define SYS_SCHEDULE_H
+
+struct Task {
+	unsigned char priority;
+	void (*task)(void);
+};
+
+#ifdef FLAT
+struct Scheduler {
+	struct Task** tasks;
+};
+#elseif LL
+#include "../lib/ll.h"
+struct Scheduler {
+	struct LL* tasks;
+};
+#else
+#include "../lib/q.h"
+struct Scheduler {
+	struct Q_base* tasks;
+};
+#endif
+
+void add_task(struct Task*);
+unsigned int get_task_length(void);
+void execute_task(void);
+
+#endif
-- 
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