From d8a8efe3e8d90ec83069d1c934ff319626e87a2d Mon Sep 17 00:00:00 2001
From: Fabian Imhof <fabian.imhof@ost.ch>
Date: Thu, 27 Feb 2025 10:13:35 +0000
Subject: add descriptor_table access_byte

---
 arch/x86_64/src/boot/boot.s                                |  4 ++--
 .../src/context_switching/descriptor_table/access_byte.cpp | 14 ++++++++++++++
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp

(limited to 'arch/x86_64/src')

diff --git a/arch/x86_64/src/boot/boot.s b/arch/x86_64/src/boot/boot.s
index 2197dce..dbea42a 100644
--- a/arch/x86_64/src/boot/boot.s
+++ b/arch/x86_64/src/boot/boot.s
@@ -197,10 +197,10 @@ _start:
     call enable_paging
     call enable_sse
 
-    cli // Clears the interrupt flag during the GDT setup
+    cli /* Clears the interrupt flag during the GDT setup */
     lgdt (global_descriptor_table_pointer)
     jmp $global_descriptor_table_code,$_transition_to_long_mode
-    // The interrupt flag is set in cpp after setting up the GDT
+    /* The interrupt flag is set in cpp after setting up the GDT */
 
     call halt
 
diff --git a/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp b/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp
new file mode 100644
index 0000000..15a0947
--- /dev/null
+++ b/arch/x86_64/src/context_switching/descriptor_table/access_byte.cpp
@@ -0,0 +1,14 @@
+#include "arch/context_switching/descriptor_table/access_byte.hpp"
+
+#include <bitset>
+
+namespace teachos::arch::context_switching::descriptor_table
+{
+  auto access_byte::contains_flags(std::bitset<8U> other) const -> bool { return (flags & other) == other; }
+
+  auto access_byte::get_privilege_level() const -> privilege_level
+  {
+    constexpr uint8_t PRIVILEGE_MASK = 0b0110'0000;
+    return static_cast<privilege_level>(flags.to_ulong() & PRIVILEGE_MASK);
+  }
+}  // namespace teachos::arch::context_switching::descriptor_table
-- 
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