start implementing TSS

1 files changed, 20 insertions, 0 deletions

diff --git a/arch/x86_64/src/kernel/cpu/gdtr.cpp b/arch/x86_64/src/kernel/cpu/gdtr.cpp
new file mode 100644
index 0000000..2fe3a99
--- /dev/null
+++ b/arch/x86_64/src/kernel/cpu/gdtr.cpp
@@ -0,0 +1,20 @@
+#include "arch/kernel/cpu/gdtr.hpp"
+
+#include "arch/context_switching/descriptor_table/global_descriptor_table_pointer.hpp"
+
+namespace teachos::arch::kernel::cpu
+{
+  auto store_global_descriptor_table() -> context_switching::descriptor_table::global_descriptor_table_pointer
+  {
+    context_switching::descriptor_table::global_descriptor_table_pointer current_value{};
+    asm("sgdt %[output]" : [output] "=m"(current_value));
+    return current_value;
+  }
+
+  auto
+  load_global_descriptor_table(context_switching::descriptor_table::global_descriptor_table_pointer const & gdt_pointer)
+      -> void
+  {
+    asm volatile("lgdt %[input]" : /* no output from call */ : [input] "m"(gdt_pointer));
+  }
+}  // namespace teachos::arch::kernel::cpu