Adjust segment descriptor to use defined helpers

3 files changed, 41 insertions, 27 deletions

diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt
index 19c71be..1b8349a 100644
--- a/arch/x86_64/CMakeLists.txt
+++ b/arch/x86_64/CMakeLists.txt
@@ -89,6 +89,7 @@ target_sources("_context" PRIVATE
   "src/context_switching/descriptor_table/gdt_flags.cpp"
   "src/context_switching/descriptor_table/access_byte.cpp"
   "src/context_switching/descriptor_table/type_field.cpp"
+  "src/context_switching/descriptor_table/segment_descriptor.cpp"
 )
 
 #[============================================================================[
diff --git a/arch/x86_64/include/arch/context_switching/descriptor_table/segment_descriptor.hpp b/arch/x86_64/include/arch/context_switching/descriptor_table/segment_descriptor.hpp
index b7665d9..59f99f6 100644
--- a/arch/x86_64/include/arch/context_switching/descriptor_table/segment_descriptor.hpp
+++ b/arch/x86_64/include/arch/context_switching/descriptor_table/segment_descriptor.hpp
@@ -1,44 +1,44 @@
 #ifndef TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_DESCRIPTOR_TABLE_SEGMENT_DESCRIPTOR_HPP
 #define TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_DESCRIPTOR_TABLE_SEGMENT_DESCRIPTOR_HPP
 
+#include "arch/context_switching/descriptor_table/access_byte.hpp"
 #include "arch/context_switching/descriptor_table/gdt_flags.hpp"
-
-#include <bitset>
+#include "arch/context_switching/descriptor_table/segment_descriptor_type.hpp"
+#include "arch/context_switching/descriptor_table/type_field.hpp"
 
 namespace teachos::arch::context_switching::descriptor_table
 {
+  __extension__ typedef __int128 int128_t;
+  __extension__ typedef unsigned __int128 uint128_t;
 
-  /*
-    TODO: Lookup segment_descriptor in intel manual chapter 3.4.5
-  */
-
+  /**
+   * @brief Defines helper function for all states and the actual data the segment descriptor can have.
+   */
   struct segment_descriptor
   {
     /**
-     * @brief Possible set bits in our underlying std::bitset and the meaning when they are set.
+     * @brief Constructor.
+     *
+     * @note Created segment descriptor copies the given bytes into theese components ending with a 32 bit reserved
+     * field that has to be used, because the 64-bit segment descriptor needs to be big enough for two 32-bit segment
+     * descriptor.
+     * - 8 bit Access Type
+     * - 4 bit Flags
+     * - 64 bit Base Address
+     * - 20 bit Limit
+     *
+     * @param flags Copies the bits set from the given data into the individual components of a segment
+     * descriptor.
      */
-    enum bitset : uint64_t
-    {
-      BASE = 1U << 0U,
-      FLAGS = 1U << 8U,
-      LIMIT = 1U << 12U,
-      ACCESS_BYTE = 1U << 16U,
-      BASE = 1U << 32U,
-      BASE = 1U << 40U,
-      LIMIT = 1U << 56U
-    };
-
-    explicit segment_descriptor(uint64_t flags)
-        : flags(flags)
-    {
-      // Nothing to do
-    }
+    explicit segment_descriptor(uint128_t flags);
 
   private:
-    std::uint8_t base1;
-    gdt_flags flags;
-    std::bitset<64U> flags;  ///< Underlying bitset used to read the flags from
+    uint32_t _reserved;
+    access_byte _access;
+    gdt_flags _flag;
+    uint64_t _base;
+    std::bitset<20U> _limit;
   };
 }  // namespace teachos::arch::context_switching::descriptor_table
 
-#endif  // TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_DESCRIPTOR_TABLE_SEGMENT_DESCRIPTOR_HPP
\ No newline at end of file
+#endif  // TEACHOS_ARCH_X86_64_CONTEXT_SWITCHING_DESCRIPTOR_TABLE_SEGMENT_DESCRIPTOR_HPP
diff --git a/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp b/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
new file mode 100644
index 0000000..fb9c034
--- /dev/null
+++ b/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
@@ -0,0 +1,13 @@
+#include "arch/context_switching/descriptor_table/segment_descriptor.hpp"
+
+namespace teachos::arch::context_switching::descriptor_table
+{
+  segment_descriptor::segment_descriptor(uint128_t flags)
+      : _reserved(flags)
+      , _access(flags)
+      , _flag(flags, segment_descriptor_type::SYSTEM_SEGMENT)
+      , _base(flags)
+      , _limit(flags)
+  {
+  }
+}  // namespace teachos::arch::context_switching::descriptor_table