IN_PROGRESS implement gdt initialization

1 files changed, 33 insertions, 0 deletions

diff --git a/arch/x86_64/src/kernel/cpu/ss.cpp b/arch/x86_64/src/kernel/cpu/ss.cpp
new file mode 100644
index 0000000..b7e52e1
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/ss.cpp
@@ -0,0 +1,33 @@
+#include "arch/kernel/cpu/ss.hpp"
+
+namespace teachos::arch::memory::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__("mov %%ss, %0" : "=r"(ss));
+    return ss;
+  }
+
+  auto write_ss(segment_selector selector) -> void
+  {
+    uint16_t ss = selector.to_uint16();
+    __asm__("mov %0, %%ss" ::"r"(ss));
+  }
+
+}  // namespace teachos::arch::memory::cpu
\ No newline at end of file