#pragma once
/// \file tss.h
/// Definitions relating to the TSS
#include <stdint.h>

/// The 64bit TSS table
class TSS
{
public:
    TSS();

    /// Get the currently running CPU's TSS.
    static TSS & current();

    /// Ring stack accessor. Returns a mutable reference.
    /// \arg ring  Which ring (0-3) to get the stack for
    /// \returns   A mutable reference to the stack pointer
    uintptr_t & ring_stack(unsigned ring);

    /// IST stack accessor. Returns a mutable reference.
    /// \arg ist   Which IST entry (1-7) to get the stack for
    /// \returns   A mutable reference to the stack pointer
    uintptr_t & ist_stack(unsigned ist);

    /// Allocate new stacks for the given IST entries.
    /// \arg ist_entries  A bitmap of used IST entries
    void create_ist_stacks(uint8_t ist_entries);

private:
    uint32_t m_reserved0;

    uintptr_t m_rsp[3]; // stack pointers for CPL 0-2
    uintptr_t m_ist[8]; // ist[0] is reserved

    uint64_t m_reserved1;
    uint16_t m_reserved2;
    uint16_t m_iomap_offset;
} __attribute__ ((packed));