From 205934ca45d591924b4be6e7ae5a8849958e0cf6 Mon Sep 17 00:00:00 2001
From: Fabian Imhof <fabian.imhof@ost.ch>
Date: Tue, 15 Oct 2024 08:23:39 +0000
Subject: continue implementing paging

---
 arch/x86_64/src/memory/paging.cpp | 36 +++++++++++++-----------------------
 1 file changed, 13 insertions(+), 23 deletions(-)

(limited to 'arch/x86_64/src/memory/paging.cpp')

diff --git a/arch/x86_64/src/memory/paging.cpp b/arch/x86_64/src/memory/paging.cpp
index 555357c..90c4199 100644
--- a/arch/x86_64/src/memory/paging.cpp
+++ b/arch/x86_64/src/memory/paging.cpp
@@ -1,34 +1,16 @@
 #include "arch/memory/paging.hpp"
 
+#include "arch/exception_handling/assert.hpp"
+
 namespace teachos::arch::memory
 {
   auto entry::is_unused() const -> bool { return flags == 0U; }
 
   auto entry::set_unused() -> void { flags = 0U; }
 
-  auto entry::present() const -> bool { return is_bit_set(0U); }
-
-  auto entry::writable() const -> bool { return is_bit_set(1U); }
-
-  auto entry::user_accessible() const -> bool { return is_bit_set(2U); }
-
-  auto entry::write_through_caching() const -> bool { return is_bit_set(3U); }
-
-  auto entry::disabled_caching() const -> bool { return is_bit_set(4U); }
-
-  auto entry::is_accessing() const -> bool { return is_bit_set(5U); }
-
-  auto entry::is_diry() const -> bool { return is_bit_set(6U); }
-
-  auto entry::is_huge_page() const -> bool { return is_bit_set(7U); }
-
-  auto entry::is_global() const -> bool { return is_bit_set(8U); }
-
-  auto entry::executing_code_forbidden() const -> bool { return is_bit_set(63U); }
-
   auto entry::calculate_pointed_to_frame() const -> std::optional<physical_frame>
   {
-    if (present())
+    if (contains_flags(1))
     {
       auto physical_address = calculate_physical_address();
       return physical_frame::containing_address(physical_address);
@@ -39,7 +21,7 @@ namespace teachos::arch::memory
   auto entry::calculate_physical_address() const -> std::size_t
   {
     constexpr std::size_t start_bit = 12U;
-    constexpr std::size_t end_bit = 51U;
+    constexpr std::size_t end_bit = 52U;
     size_t value = 0U;
 
     for (auto i = start_bit; i < end_bit; i++)
@@ -49,5 +31,13 @@ namespace teachos::arch::memory
     return value;
   }
 
-  auto entry::is_bit_set(uint8_t index) const -> bool { return flags[index] == 1U; }
+  auto entry::set(physical_frame frame) -> void
+  {
+    arch::exception_handling::assert((frame.start_address() & ~0x000fffff'fffff000) == 0,
+                                     "Start address is not aligned with Page");
+    flags = std::bitset<64U>(frame.start_address()) | flags;
+  }
+
+  auto entry::contains_flags(std::bitset<64U> b) const -> bool { return (flags & b) == b; }
+
 }  // namespace teachos::arch::memory
-- 
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