old-MTGos-old/kernel/hal/x86/init/Multitasking.cpp

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#include <base.hpp>
#include <textDISP.hpp>
#include <Multitasking.hpp>
#include <serial.hpp>
#include <blockdev.hpp>
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#include <vmm3.hpp>
auto schedule(struct cpu_state* cpu) -> struct cpu_state* {
return MTGosHAL::tasks.schedule(cpu);
}
namespace MTGosHAL {
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Multitasking::Multitasking(): curr_task(nullptr), first_task(nullptr)
{
for(int i=0;i<32;i++) {
if(i==2)
continue;
tss[i]=0;
}
tss[2]=0x10;
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//task_states[0] = initTask(stack_a, user_stack_a, task_a);
//task_states[1] = initTask(stack_b, user_stack_b, task_b);
if(!idt.request(0x20,::schedule)) {
err << "Could not start multitasking\nFatal error; Kernel halted!\n";
while(true)
asm volatile("cli; hlt");
}
}
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auto Multitasking::initTask(void(* entry)()) -> struct cpu_state*
{
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void* tmp1, *tmp2;
mm.pmm.pmm2 >> tmp1 >> tmp2;
uint8_t *stack=(uint8_t*)tmp1, *user_stack=(uint8_t*)tmp2;
struct cpu_state new_state = {
0, //EAX
0, //EBX
0, //ECX
0, //EDX
0, //ESI
0, //EDI
0, //EBP
0, //INTR
0, //ERROR
(uint32_t) entry, //EIP
0x18 | 0x03, //CS
0x202, // EFLAGS
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(uint32_t) user_stack+4096, //ESP
0x20 | 0x03 //SS
};
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struct cpu_state* state = (struct cpu_state*)(stack+4096-sizeof(new_state));
*state = new_state;
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//Create new task class
Task* task = new Task(state);
if(first_task)
first_task->addTask(task);
else {
first_task=task;
}
return state;
}
auto Multitasking::schedule(struct cpu_state* cpu) -> struct cpu_state*
{
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Task* next=nullptr;
if(curr_task) {
next=curr_task->pause(cpu);
}
if (!next) {
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next=first_task;
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}
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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* {
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MTGosHAL::tasks.tss[1] = (uint32_t) (cpu_state + 1);
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return cpu_state;
}
//This is run every time the timer ticks and a task is running
auto Task::pause(struct cpu_state* cpu) -> Task * {
cpu_state=cpu;
return next;
}
auto Task::addTask(Task* task) -> void {
if(next)
return next->addTask(task);
next=task;
}
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auto Task::hasNext() -> bool {
return next!=nullptr;
}
} // namespace MTGosHAL