#include "arch/kernel/cpu/ss.hpp"

namespace teachos::arch::kernel::cpu
{
  segment_selector::segment_selector(uint16_t index, std::bitset<1U> table_indicator,
                                     std::bitset<2U> requested_privilege_level)
      : index(index)
      , table_indicator(table_indicator)
      , requested_privilege_level(requested_privilege_level)
  {
    // Nothing to do
  }

  auto segment_selector::to_uint16() const -> uint16_t
  {
    return static_cast<uint16_t>((index << 3) | (table_indicator.to_ulong() << 2) |
                                 requested_privilege_level.to_ulong());
  }

  auto read_ss() -> uint16_t
  {
    uint16_t ss;
    asm volatile("mov %%ss, %0" : "=r"(ss));
    return ss;
  }

  auto write_ss(segment_selector selector) -> void
  {
    uint16_t ss = selector.to_uint16();
    asm volatile("mov %0, %%ss" ::"r"(ss));
  }

}  // namespace teachos::arch::kernel::cpu