From 2cc45e996f7542e50930574f7cfe4e90ae745d76 Mon Sep 17 00:00:00 2001
From: Morten Delenk <mtg.morten@googlemail.com>
Date: Fri, 22 Apr 2016 15:07:52 +0200
Subject: [PATCH] Fixed multitasking bugs

---
 kernel/hal/dummy/include/Multitasking.h |  3 +--
 kernel/hal/x86/include/Multitasking.hpp |  3 +--
 kernel/hal/x86/init/Multitasking.cpp    | 33 ++++++++-----------------
 kernel/kernel/init.cpp                  | 16 +++++++++---
 4 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/kernel/hal/dummy/include/Multitasking.h b/kernel/hal/dummy/include/Multitasking.h
index cca8158..41f4b9c 100644
--- a/kernel/hal/dummy/include/Multitasking.h
+++ b/kernel/hal/dummy/include/Multitasking.h
@@ -11,8 +11,6 @@ namespace MTGosHAL {
           uint32_t tss[32];
       protected:
       private:
-          static auto task_a() -> void;
-          static auto task_b() -> void;
           Task* first_task;
           Task* curr_task;
   };
@@ -26,6 +24,7 @@ namespace MTGosHAL {
     auto unpause() -> struct cpu_state*;
     auto pause(struct cpu_state*) -> Task *;
     auto addTask(Task*) -> void;
+    auto hasNext() -> bool;
   };
 
 } // namespace MTGosHAL
diff --git a/kernel/hal/x86/include/Multitasking.hpp b/kernel/hal/x86/include/Multitasking.hpp
index 3949622..2afe622 100644
--- a/kernel/hal/x86/include/Multitasking.hpp
+++ b/kernel/hal/x86/include/Multitasking.hpp
@@ -14,8 +14,6 @@ namespace MTGosHAL {
             uint32_t tss[32];
         protected:
         private:
-            static auto task_a() -> void;
-            static auto task_b() -> void;
             Task* first_task;
             Task* curr_task;
     };
@@ -29,6 +27,7 @@ namespace MTGosHAL {
       auto unpause() -> struct cpu_state*;
       auto pause(struct cpu_state*) -> Task *;
       auto addTask(Task*) -> void;
+      auto hasNext() -> bool;
     };
 
 } // namespace MTGosHAL
diff --git a/kernel/hal/x86/init/Multitasking.cpp b/kernel/hal/x86/init/Multitasking.cpp
index b0ea7ec..94443d1 100644
--- a/kernel/hal/x86/init/Multitasking.cpp
+++ b/kernel/hal/x86/init/Multitasking.cpp
@@ -55,40 +55,24 @@ auto Multitasking::initTask(void(* entry)()) -> struct cpu_state*
     else {
       first_task=task;
     }
-    curr_task=first_task;
     return state;
 }
-
-auto Multitasking::task_a() -> void
-{
-    while(true) {
-      char arr[513];
-      arr[512]=0;
-      disk.readSector(disk.getDriveNumByName("ATA0m"),0,(uint8_t*)arr);
-      out << arr;
-    }
-}
-
-auto Multitasking::task_b() -> void
-{
-  while(true) {
-    char arr[513];
-    arr[512]=0;
-    disk.readSector(disk.getDriveNumByName("ATA0m"),1,(uint8_t*)arr);
-    out << arr;
-  }
-}
 auto Multitasking::schedule(struct cpu_state* cpu) -> struct cpu_state*
 {
-  Task* next=curr_task->pause(cpu);
-  if(next==nullptr)
+  Task* next=nullptr;
+  if(curr_task) {
+    next=curr_task->pause(cpu);
+  }
+  if (!next) {
     next=first_task;
+  }
   curr_task=next;
   return next->unpause();
 }
 Task::Task(struct cpu_state* cpu): cpu_state(cpu), next(nullptr) {};
 //This is run every time this task is chosen by the scheduler
 auto Task::unpause() -> struct cpu_state* {
+  MTGosHAL::tasks.tss[1] = (uint32_t) (cpu_state + 1);
   return cpu_state;
 }
 //This is run every time the timer ticks and a task is running
@@ -101,4 +85,7 @@ auto Task::addTask(Task* task) -> void {
     return next->addTask(task);
   next=task;
 }
+auto Task::hasNext() -> bool {
+  return next!=nullptr;
+}
 } // namespace MTGosHAL
diff --git a/kernel/kernel/init.cpp b/kernel/kernel/init.cpp
index cd8c0d6..277fe18 100644
--- a/kernel/kernel/init.cpp
+++ b/kernel/kernel/init.cpp
@@ -6,20 +6,28 @@
 #include <Multitasking.h>
 #include <blockdev.hpp>
 using namespace MTGosHAL;
+void pid_null() {
+  for(;;);
+}
 void task_a() {
-  MTGosHAL::out << "a";
+  while(true)
+    MTGosHAL::out << "a";
 }
 void task_b() {
-  MTGosHAL::out << "b";
+  while(true)
+    MTGosHAL::out << "b";
 }
 void task_c() {
-  MTGosHAL::out << "c";
+  while(true)
+    MTGosHAL::out << "c";
 }
 void task_d() {
-  MTGosHAL::out << "d";
+  while(true)
+    MTGosHAL::out << "d";
 }
 void main() {
     MTGosHAL::out << "Initializing Kernel!\n";
+    MTGosHAL::tasks.initTask(&pid_null);
     MTGosHAL::tasks.initTask(&task_a);
     MTGosHAL::tasks.initTask(&task_b);
     MTGosHAL::tasks.initTask(&task_c);