From 12aa014a3dcb18ea6ef2d36816e9fbccbfb7d659 Mon Sep 17 00:00:00 2001
From: apio <blobs.trading@gmail.com>
Date: Wed, 7 Dec 2022 15:02:46 +0100
Subject: [PATCH] Add a Thread class which can be part of a DoublyLinkedList

---
 kernel/src/arch/x86_64/Thread.cpp | 49 +++++++++++++++++++++++++++++++
 kernel/src/thread/Thread.cpp      | 15 ++++++++++
 kernel/src/thread/Thread.h        | 46 +++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 kernel/src/arch/x86_64/Thread.cpp
 create mode 100644 kernel/src/thread/Thread.cpp
 create mode 100644 kernel/src/thread/Thread.h

diff --git a/kernel/src/arch/x86_64/Thread.cpp b/kernel/src/arch/x86_64/Thread.cpp
new file mode 100644
index 00000000..1abd34a0
--- /dev/null
+++ b/kernel/src/arch/x86_64/Thread.cpp
@@ -0,0 +1,49 @@
+#include "thread/Thread.h"
+#include <luna/String.h>
+
+bool is_in_kernel(Registers* regs)
+{
+    return regs->cs == 8;
+}
+
+void Thread::set_ip(u64 ip)
+{
+    regs.rip = ip;
+}
+
+u64 Thread::ip()
+{
+    return regs.rip;
+}
+
+void Thread::set_sp(u64 sp)
+{
+    regs.rsp = sp;
+}
+
+u64 Thread::sp()
+{
+    return regs.rsp;
+}
+
+void Thread::init_regs_kernel()
+{
+    memset(&regs, 0, sizeof(Registers));
+    regs.cs = 0x08;
+    regs.ss = 0x10;
+}
+
+void Thread::set_arguments(u64 arg1, u64 arg2, u64 arg3, u64 arg4)
+{
+    regs.rdi = arg1;
+    regs.rsi = arg2;
+    regs.rdx = arg3;
+    regs.rcx = arg4;
+}
+
+void switch_context(Thread* old_thread, Thread* new_thread, Registers* regs)
+{
+    if (!old_thread->is_idle) memcpy(&old_thread->regs, regs, sizeof(Registers));
+
+    memcpy(regs, &new_thread->regs, sizeof(Registers));
+}
\ No newline at end of file
diff --git a/kernel/src/thread/Thread.cpp b/kernel/src/thread/Thread.cpp
new file mode 100644
index 00000000..5f834d6e
--- /dev/null
+++ b/kernel/src/thread/Thread.cpp
@@ -0,0 +1,15 @@
+#include "thread/Thread.h"
+#include <luna/Alloc.h>
+
+static u64 g_next_id = 1;
+
+DoublyLinkedList<Thread> g_threads;
+
+Result<Thread*> new_thread()
+{
+    Thread* thread = TRY(make<Thread>());
+
+    thread->id = g_next_id++;
+
+    return thread;
+}
\ No newline at end of file
diff --git a/kernel/src/thread/Thread.h b/kernel/src/thread/Thread.h
new file mode 100644
index 00000000..3b3b7a39
--- /dev/null
+++ b/kernel/src/thread/Thread.h
@@ -0,0 +1,46 @@
+#pragma once
+
+#include "arch/CPU.h"
+#include <luna/LinkedList.h>
+#include <luna/Result.h>
+
+#ifdef ARCH_X86_64
+#include "arch/x86_64/CPU.h"
+#else
+#error "Unknown architecture."
+#endif
+
+struct Thread : public DoublyLinkedListNode<Thread>
+{
+    Registers regs;
+
+    u64 id;
+
+    u64 ticks = 0;
+    u64 ticks_in_user = 0;
+    u64 ticks_in_kernel = 0;
+
+    u64 ticks_left;
+
+    bool is_idle = false;
+
+    void init_regs_kernel();
+    void init_regs_user();
+
+    void set_arguments(u64 arg1, u64 arg2, u64 arg3, u64 arg4);
+
+    void set_ip(u64 ip);
+    u64 ip();
+
+    void set_sp(u64 sp);
+    u64 sp();
+};
+
+void switch_context(Thread* old_thread, Thread* new_thread, Registers* regs);
+
+bool is_in_kernel(Registers* regs);
+
+Result<Thread*> new_thread();
+Result<Thread*> create_idle_thread();
+
+extern DoublyLinkedList<Thread> g_threads;
\ No newline at end of file