Improve create_segment readability

11 files changed, 106 insertions, 58 deletions

diff --git a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/idt_flags.hpp b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/idt_flags.hpp
index f153e36..2f8e61d 100644
--- a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/idt_flags.hpp
+++ b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/idt_flags.hpp
@@ -48,13 +48,13 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
     idt_flags(uint8_t flags);
 
     /**
-     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying std::bitset.
+     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying data.
      *
      * @note Meaning that all bits that are set in the given std::bitset also have to be set in the underlyng
-     * std::bitset. Any additional bits that are set are not relevant.
+     * data. Any additional bits that are set are not relevant.
      *
-     * @param other Flags that we want to compare against and check if the underlying std::bitset has the same bits set.
-     * @return Whether the given flags are a subset or equivalent with the underlying std::bitset.
+     * @param other Flags that we want to compare against and check if the underlying data has the same bits set.
+     * @return Whether the given flags are a subset or equivalent with the underlying data.
      */
     auto contains_flags(std::bitset<8U> other) const -> bool;
 
@@ -66,6 +66,13 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
      */
     auto operator==(idt_flags const & other) const -> bool = default;
 
+    /**
+     * @brief Combines all bits that are set in the std::bitset flags with the bits already set in the underlying data.
+     *
+     * @param other Additional bits that should be set.
+     */
+    auto operator|=(std::bitset<8U> other) -> void;
+
   private:
     uint8_t _flags = {};  ///< Underlying bits used to read the flags from.
   };
diff --git a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp
index 73cd176..2c90152 100644
--- a/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp
+++ b/arch/x86_64/include/arch/context_switching/interrupt_descriptor_table/segment_selector.hpp
@@ -51,13 +51,13 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
     segment_selector(uint16_t index, uint8_t flags);
 
     /**
-     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying std::bitset.
+     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying data.
      *
      * @note Meaning that all bits that are set in the given std::bitset also have to be set in the underlyng
-     * std::bitset. Any additional bits that are set are not relevant.
+     * data. Any additional bits that are set are not relevant.
      *
-     * @param other Flags that we want to compare against and check if the underlying std::bitset has the same bits set.
-     * @return Whether the given flags are a subset or equivalent with the underlying std::bitset.
+     * @param other Flags that we want to compare against and check if the underlying data has the same bits set.
+     * @return Whether the given flags are a subset or equivalent with the underlying data.
      */
     auto contains_flags(std::bitset<3U> other) const -> bool;
 
@@ -66,6 +66,13 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
      */
     auto operator<=>(segment_selector const & other) const -> std::strong_ordering = default;
 
+    /**
+     * @brief Combines all bits that are set in the std::bitset flags with the bits already set in the underlying data.
+     *
+     * @param other Additional bits that should be set.
+     */
+    auto operator|=(std::bitset<3U> other) -> void;
+
   private:
     uint8_t _flags : 3 = {};  ///< Underlying bits used to read the flags from.
     uint16_t _index : 13 =
diff --git a/arch/x86_64/include/arch/context_switching/segment_descriptor_table/access_byte.hpp b/arch/x86_64/include/arch/context_switching/segment_descriptor_table/access_byte.hpp
index 3d7862c..621b570 100644
--- a/arch/x86_64/include/arch/context_switching/segment_descriptor_table/access_byte.hpp
+++ b/arch/x86_64/include/arch/context_switching/segment_descriptor_table/access_byte.hpp
@@ -71,24 +71,31 @@ namespace teachos::arch::context_switching::segment_descriptor_table
     access_byte(uint8_t flags);
 
     /**
-     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying std::bitset.
+     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying data.
      *
      * @note Meaning that all bits that are set in the given std::bitset also have to be set in the underlyng
-     * std::bitset. Any additional bits that are set are not relevant.
+     * data. Any additional bits that are set are not relevant.
      *
-     * @param other Flags that we want to compare against and check if the underlying std::bitset has the same bits set.
-     * @return Whether the given flags are a subset or equivalent with the underlying std::bitset.
+     * @param other Flags that we want to compare against and check if the underlying data has the same bits set.
+     * @return Whether the given flags are a subset or equivalent with the underlying data.
      */
     auto contains_flags(std::bitset<8U> other) const -> bool;
 
     /**
-     * @brief Allows to compare the underlying std::bitset of two instances.
+     * @brief Allows to compare the underlying data of two instances.
      *
      * @param other Other instance that we want to compare with.
-     * @return Whether the underlying std::bitset of both types is the same.
+     * @return Whether the underlying data of both types is the same.
      */
     auto operator==(access_byte const & other) const -> bool = default;
 
+    /**
+     * @brief Combines all bits that are set in the std::bitset flags with the bits already set in the underlying data.
+     *
+     * @param other Additional bits that should be set.
+     */
+    auto operator|=(std::bitset<8U> other) -> void;
+
   private:
     uint8_t _flags = {};  ///< Underlying bits used to read the flags from.
   };
diff --git a/arch/x86_64/include/arch/context_switching/segment_descriptor_table/gdt_flags.hpp b/arch/x86_64/include/arch/context_switching/segment_descriptor_table/gdt_flags.hpp
index d8c3cd1..4b84035 100644
--- a/arch/x86_64/include/arch/context_switching/segment_descriptor_table/gdt_flags.hpp
+++ b/arch/x86_64/include/arch/context_switching/segment_descriptor_table/gdt_flags.hpp
@@ -50,13 +50,13 @@ namespace teachos::arch::context_switching::segment_descriptor_table
     gdt_flags(uint8_t flags, std::bitset<20U> limit);
 
     /**
-     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying std::bitset.
+     * @brief Checks if the given std::bitset is a subset or equivalent to the underlying data.
      *
      * @note Meaning that all bits that are set in the given std::bitset also have to be set in the underlyng
-     * std::bitset. Any additional bits that are set are not relevant.
+     * data. Any additional bits that are set are not relevant.
      *
-     * @param other Flags that we want to compare against and check if the underlying std::bitset has the same bits set.
-     * @return Whether the given flags are a subset or equivalent with the underlying std::bitset.
+     * @param other Flags that we want to compare against and check if the underlying data has the same bits set.
+     * @return Whether the given flags are a subset or equivalent with the underlying data.
      */
     auto contains_flags(std::bitset<4U> other) const -> bool;
 
@@ -77,6 +77,13 @@ namespace teachos::arch::context_switching::segment_descriptor_table
      */
     auto operator==(gdt_flags const & other) const -> bool = default;
 
+    /**
+     * @brief Combines all bits that are set in the std::bitset flags with the bits already set in the underlying data.
+     *
+     * @param other Additional bits that should be set.
+     */
+    auto operator|=(std::bitset<4U> other) -> void;
+
   private:
     uint8_t _limit_2 : 4 = {};  ///< Second part of the limit field.
     uint8_t _flags : 4 = {};    ///< Underlying bits used to read the flags from.
diff --git a/arch/x86_64/src/context_switching/interrupt_descriptor_table/idt_flags.cpp b/arch/x86_64/src/context_switching/interrupt_descriptor_table/idt_flags.cpp
index e7379ef..d36a4c1 100644
--- a/arch/x86_64/src/context_switching/interrupt_descriptor_table/idt_flags.cpp
+++ b/arch/x86_64/src/context_switching/interrupt_descriptor_table/idt_flags.cpp
@@ -12,4 +12,6 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
   {
     return (std::bitset<8U>{_flags} & other) == other;
   }
+
+  auto idt_flags::operator|=(std::bitset<8U> other) -> void { _flags |= other.to_ulong(); }
 }  // namespace teachos::arch::context_switching::interrupt_descriptor_table
diff --git a/arch/x86_64/src/context_switching/interrupt_descriptor_table/interrupt_descriptor_table.cpp b/arch/x86_64/src/context_switching/interrupt_descriptor_table/interrupt_descriptor_table.cpp
index 62b116b..db3351e 100644
--- a/arch/x86_64/src/context_switching/interrupt_descriptor_table/interrupt_descriptor_table.cpp
+++ b/arch/x86_64/src/context_switching/interrupt_descriptor_table/interrupt_descriptor_table.cpp
@@ -6,18 +6,28 @@
 
 namespace teachos::arch::context_switching::interrupt_descriptor_table
 {
-  auto get_or_create_interrupt_descriptor_table() -> interrupt_descriptor_table &
+  namespace
   {
-    // @MTO: This address resolution is most certainly wrong -> numbers in dbg seem off (offset_3 = 0)
-    uint64_t offset = reinterpret_cast<uint64_t>(&interrupt_handling::generic_interrupt_handler);
-    segment_selector selector{0U, segment_selector::REQUEST_LEVEL_KERNEL};
-    ist_offset ist{0U};
-    idt_flags flags{idt_flags::DESCRIPTOR_LEVEL_KERNEL | idt_flags::PRESENT};
-    gate_descriptor descriptor{selector, ist, flags, offset};
+    auto create_interrupt_descriptor_table() -> interrupt_descriptor_table
+    {
+      // @MTO: This address resolution is most certainly wrong -> numbers in dbg seem off (offset_3 = 0)
+      uint64_t offset = reinterpret_cast<uint64_t>(&interrupt_handling::generic_interrupt_handler);
+      segment_selector selector{0U, segment_selector::REQUEST_LEVEL_KERNEL};
+      ist_offset ist{0U};
+      idt_flags flags{idt_flags::DESCRIPTOR_LEVEL_KERNEL | idt_flags::PRESENT};
+      gate_descriptor descriptor{selector, ist, flags, offset};
+
+      // Interrupt Descriptor Table needs to be kept alive
+      static interrupt_descriptor_table interrupt_descriptor_table{descriptor};
+      return interrupt_descriptor_table;
+    }
+  }  // namespace
 
+  auto get_or_create_interrupt_descriptor_table() -> interrupt_descriptor_table &
+  {
     // Interrupt Descriptor Table needs to be kept alive
-    static interrupt_descriptor_table interrupt_descriptor_table{descriptor};
-    return interrupt_descriptor_table;
+    static interrupt_descriptor_table idt = create_interrupt_descriptor_table();
+    return idt;
   }
 
   auto update_interrupt_descriptor_table_register() -> void
diff --git a/arch/x86_64/src/context_switching/interrupt_descriptor_table/segment_selector.cpp b/arch/x86_64/src/context_switching/interrupt_descriptor_table/segment_selector.cpp
index 494e50f..62aed9b 100644
--- a/arch/x86_64/src/context_switching/interrupt_descriptor_table/segment_selector.cpp
+++ b/arch/x86_64/src/context_switching/interrupt_descriptor_table/segment_selector.cpp
@@ -13,4 +13,6 @@ namespace teachos::arch::context_switching::interrupt_descriptor_table
   {
     return (std::bitset<3U>{_flags} & other) == other;
   }
+
+  auto segment_selector::operator|=(std::bitset<3U> other) -> void { _flags |= other.to_ulong(); }
 }  // namespace teachos::arch::context_switching::interrupt_descriptor_table
diff --git a/arch/x86_64/src/context_switching/main.cpp b/arch/x86_64/src/context_switching/main.cpp
index db04b52..2b853ec 100644
--- a/arch/x86_64/src/context_switching/main.cpp
+++ b/arch/x86_64/src/context_switching/main.cpp
@@ -24,8 +24,6 @@ namespace teachos::arch::context_switching
 
     // FIXME: We currently cannot enable interrupts, since for some reason, we will later run into what looks like a GP
     // and triple fault.
-    // @MTO: SOMETIMES i get past a breakpoint here???? seems to happen when i actually pause before (f.e. inside the
-    // idt). NEVER happened when stepping through quickly. Can you reproduce this?
     kernel::cpu::set_interrupt_flag();
 
     descriptor_tables tables = {segment_descriptor_table::get_or_create_global_descriptor_table(),
diff --git a/arch/x86_64/src/context_switching/segment_descriptor_table/access_byte.cpp b/arch/x86_64/src/context_switching/segment_descriptor_table/access_byte.cpp
index 34a10f1..e31e021 100644
--- a/arch/x86_64/src/context_switching/segment_descriptor_table/access_byte.cpp
+++ b/arch/x86_64/src/context_switching/segment_descriptor_table/access_byte.cpp
@@ -12,4 +12,6 @@ namespace teachos::arch::context_switching::segment_descriptor_table
   {
     return (std::bitset<8U>{_flags} & other) == other;
   }
+
+  auto access_byte::operator|=(std::bitset<8U> other) -> void { _flags |= other.to_ulong(); }
 }  // namespace teachos::arch::context_switching::segment_descriptor_table
diff --git a/arch/x86_64/src/context_switching/segment_descriptor_table/gdt_flags.cpp b/arch/x86_64/src/context_switching/segment_descriptor_table/gdt_flags.cpp
index 9885bda..e444a24 100644
--- a/arch/x86_64/src/context_switching/segment_descriptor_table/gdt_flags.cpp
+++ b/arch/x86_64/src/context_switching/segment_descriptor_table/gdt_flags.cpp
@@ -15,4 +15,6 @@ namespace teachos::arch::context_switching::segment_descriptor_table
   }
 
   auto gdt_flags::get_limit() const -> std::bitset<4U> { return std::bitset<4U>{_limit_2}; }
+
+  auto gdt_flags::operator|=(std::bitset<4U> other) -> void { _flags |= other.to_ulong(); }
 }  // namespace teachos::arch::context_switching::segment_descriptor_table
diff --git a/arch/x86_64/src/context_switching/segment_descriptor_table/global_descriptor_table.cpp b/arch/x86_64/src/context_switching/segment_descriptor_table/global_descriptor_table.cpp
index 346db9e..a497632 100644
--- a/arch/x86_64/src/context_switching/segment_descriptor_table/global_descriptor_table.cpp
+++ b/arch/x86_64/src/context_switching/segment_descriptor_table/global_descriptor_table.cpp
@@ -11,28 +11,26 @@ namespace teachos::arch::context_switching::segment_descriptor_table
 {
   namespace
   {
-
     auto create_segment_descriptor(segment_descriptor_type segment_descriptor_type, access_byte access_level)
         -> segment_descriptor
     {
-      uint8_t access_level_bits =
-          access_byte::PRESENT | access_byte::CODE_OR_DATA_SEGMENT | *reinterpret_cast<uint8_t *>(&access_level);
-      uint8_t gdt_flags_bits = gdt_flags::GRANULARITY | gdt_flags::LONG_MODE;
+      uint64_t const base = 0x0;
+      std::bitset<20U> const limit{0xFFFFF};
+      gdt_flags flags{gdt_flags::GRANULARITY, limit};
+
+      access_level |= access_byte::PRESENT | access_byte::CODE_OR_DATA_SEGMENT;
       if (segment_descriptor_type == segment_descriptor_type::CODE_SEGMENT)
       {
-        access_level_bits |= access_byte::CODE_SEGMENT | access_byte::READABLE;
+        flags |= gdt_flags::LONG_MODE;
+        access_level |= access_byte::CODE_SEGMENT | access_byte::READABLE;
       }
       else if (segment_descriptor_type == segment_descriptor_type::DATA_SEGMENT)
       {
-        gdt_flags_bits |= gdt_flags::UPPER_BOUND;
-        access_level_bits |= access_byte::WRITABLE;
+        flags |= gdt_flags::UPPER_BOUND;
+        access_level |= access_byte::WRITABLE;
       }
 
-      uint64_t const base = 0x0;
-      std::bitset<20U> const limit{0xFFFFF};
-      access_byte const access_byte{access_level_bits};
-      gdt_flags const gdt_flags{gdt_flags_bits, limit};
-      segment_descriptor const segment_descriptor{access_byte, gdt_flags, base, limit};
+      segment_descriptor const segment_descriptor{access_level, flags, base, limit};
       return segment_descriptor;
     }
 
@@ -46,28 +44,34 @@ namespace teachos::arch::context_switching::segment_descriptor_table
                                               TSS_LIMIT};
       return tss_descriptor;
     }
+
+    auto create_global_descriptor_table() -> global_descriptor_table
+    {
+      segment_descriptor const null_segment{0};
+      segment_descriptor const kernel_code_segment =
+          create_segment_descriptor(segment_descriptor_type::CODE_SEGMENT, access_byte::DESCRIPTOR_LEVEL_KERNEL);
+      segment_descriptor const kernel_data_segment =
+          create_segment_descriptor(segment_descriptor_type::DATA_SEGMENT, access_byte::DESCRIPTOR_LEVEL_KERNEL);
+      segment_descriptor const user_code_segment =
+          create_segment_descriptor(segment_descriptor_type::CODE_SEGMENT, access_byte::DESCRIPTOR_LEVEL_USER);
+      segment_descriptor const user_data_segment =
+          create_segment_descriptor(segment_descriptor_type::DATA_SEGMENT, access_byte::DESCRIPTOR_LEVEL_USER);
+
+      // Task State Segment needs to be kept alive
+      static auto tss = new task_state_segment();
+      segment_descriptor const tss_descriptor = create_task_state_segment_descriptor(tss);
+
+      global_descriptor_table global_descriptor_table{null_segment,      kernel_code_segment, kernel_data_segment,
+                                                      user_code_segment, user_data_segment,   tss_descriptor};
+      return global_descriptor_table;
+    }
   }  // namespace
 
   auto get_or_create_global_descriptor_table() -> global_descriptor_table &
   {
-    segment_descriptor const null_segment{0};
-    segment_descriptor const kernel_code_segment =
-        create_segment_descriptor(segment_descriptor_type::CODE_SEGMENT, access_byte::DESCRIPTOR_LEVEL_KERNEL);
-    segment_descriptor const kernel_data_segment =
-        create_segment_descriptor(segment_descriptor_type::DATA_SEGMENT, access_byte::DESCRIPTOR_LEVEL_KERNEL);
-    segment_descriptor const user_code_segment =
-        create_segment_descriptor(segment_descriptor_type::CODE_SEGMENT, access_byte::DESCRIPTOR_LEVEL_USER);
-    segment_descriptor const user_data_segment =
-        create_segment_descriptor(segment_descriptor_type::DATA_SEGMENT, access_byte::DESCRIPTOR_LEVEL_USER);
-
-    // Task State Segment needs to be kept alive
-    static auto tss = new task_state_segment();
-    segment_descriptor const tss_descriptor = create_task_state_segment_descriptor(tss);
-
     // Global Descriptor Table needs to be kept alive
-    static global_descriptor_table global_descriptor_table{null_segment,      kernel_code_segment, kernel_data_segment,
-                                                           user_code_segment, user_data_segment,   tss_descriptor};
-    return global_descriptor_table;
+    static global_descriptor_table gdt = create_global_descriptor_table();
+    return gdt;
   }
 
   auto update_global_descriptor_table_register() -> void