Implement segment descriptor

2 files changed, 18 insertions, 21 deletions

diff --git a/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp b/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
index 8e1e939..8fbf869 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/gdt_flags.cpp
@@ -4,24 +4,10 @@
 
 namespace teachos::arch::context_switching::descriptor_table
 {
-  gdt_flags::gdt_flags(uint8_t flags, segment_descriptor_type type)
+  gdt_flags::gdt_flags(uint8_t flags)
       : _flags(flags << 5U)
   {
-    switch (type)
-    {
-      case segment_descriptor_type::SYSTEM_SEGMENT:
-        _flags.set(2, false);
-        _flags.set(3, false);
-        break;
-      case segment_descriptor_type::DATA_SEGMENT:
-        _flags.set(3, false);
-        break;
-      case segment_descriptor_type::CODE_SEGMENT:
-        exception_handling::assert((contains_flags(LENGTH) && !contains_flags(DEFAULT_LENGTH)) ||
-                                       !contains_flags(LENGTH),
-                                   "[GDT] Flags of code segment descriptor has both ");
-        break;
-    }
+    // Nothing to do.
   }
 
   auto gdt_flags::contains_flags(std::bitset<4U> other) const -> bool { return (_flags & other) == other; }
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
index fb9c034..57564f2 100644
--- a/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
+++ b/arch/x86_64/src/context_switching/descriptor_table/segment_descriptor.cpp
@@ -3,11 +3,22 @@
 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)
+      : _reserved(flags >> 96U)
+      , _access((flags >> 40U) << 80U)
+      , _flag((flags >> 52U) << 72U)
+      , _base(((flags >> 64U) << 32U) << 32U | ((flags >> 56U) << 64U) << 24U | (flags >> 16U) << 88U)
+      , _limit(((flags >> 48U) << 72U) << 16U | flags << 112U)
   {
+    // Nothing to do.
+  }
+
+  auto segment_descriptor::get_segment_type() const -> segment_descriptor_type
+  {
+    if (!_access.contains_flags(access_byte::CODE_OR_DATA_SEGMENT))
+    {
+      return segment_descriptor_type::SYSTEM_SEGMENT;
+    }
+    return _access.get_type_field().contains_flags(type_field::CODE_SEGMENT) ? segment_descriptor_type::CODE_SEGMENT
+                                                                             : segment_descriptor_type::DATA_SEGMENT;
   }
 }  // namespace teachos::arch::context_switching::descriptor_table