SV32 translation test with basic PageTableWalk (#20)

This PR introduces a basic implementation of the SV32 page table walk,
following a test-driven approach. A test was written to validate the
functionality, which led to defining the `sv32PageTableWalk` method for
address translation. The current implementation of `sv32PageTableWalk`
checks the validity of PTEs but does not include comprehensive checks
for other conditions. This sets up a foundation for further enhancement
in the page table walk process, with future iterations expected to
include more advanced validations.

---------

Co-authored-by: Kathlene Magnus <[email protected]>

core/CMakeLists.txt

@@ -10,6 +10,7 @@ add_library(atlascore
     Execute.cpp
     AtlasExtractor.cpp
     AtlasInst.cpp
+    PageTableWalker.cpp
     observers/Observer.cpp
     observers/CoSimObserver.cpp
     observers/InstructionLogger.cpp

core/PageTable.hpp

@@ -1,3 +1,5 @@
+#pragma once
+
 #include <map>
 #include <iostream>
 #include "../include/AtlasTypes.hpp"
@@ -10,25 +12,110 @@ namespace atlas
       private:
         const uint16_t max_entries;
         const uint32_t baseAddressOfpageTable;
-        bool isValidIndex(uint32_t idx);
-        size_t size();
-        uint16_t getMaxNumEntries(MMUMode mode) const;
+
+        bool isValidIndex(uint32_t idx)
+        {
+            uint32_t pte_size = (Mode == MMUMode::SV32) ? sizeof(RV32) : sizeof(RV64);
+            return ((idx >= baseAddressOfpageTable)
+                    && (idx < ((max_entries * pte_size) + baseAddressOfpageTable)));
+        }
+
+        size_t size() const { return pageTable.size(); }
+
+        uint16_t getMaxNumEntries() const
+        {
+            if (Mode == MMUMode::SV32)
+                return PT_ENTRIES_SV32;
+            else if (Mode == MMUMode::SV39)
+                return PT_ENTRIES_SV39;
+            return 0;
+        }
 
       public:
         std::map<uint32_t, PageTableEntry<Mode>>
-            pageTable; // uint32_t will be able to accomodate all the types of indexes(VPNs) for
-                       // addressing the PTE
-
-        PageTable(uint32_t baseAddr);
-        void addEntry(uint32_t index, PageTableEntry<Mode> entry);
-        PageTableEntry<Mode> getEntry(uint32_t index);
-        void removeEntry(uint32_t index);
-        void print(std::ostream & os);
-        bool contains(uint32_t index);
+            pageTable; // uint32_t accommodates all types of VPNs for addressing the PTE
+
+        PageTable(uint32_t baseAddr) :
+            max_entries(getMaxNumEntries()),
+            baseAddressOfpageTable(baseAddr)
+        {
+        }
+
+        void addEntry(uint32_t index, PageTableEntry<Mode> entry)
+        {
+            if (size() <= max_entries && isValidIndex(index))
+            {
+                auto it = pageTable.find(index);
+                if (it != pageTable.end())
+                {
+                    it->second = entry; // Update the existing entry
+                }
+                else
+                {
+                    pageTable.insert({index, entry}); // Insert the new entry
+                }
+            }
+            else
+            {
+                throw std::runtime_error(
+                    "Page table has reached its maximum capacity or index is out of bounds!");
+            }
+        }
+
+        PageTableEntry<Mode> getEntry(uint32_t index)
+        {
+            if (isValidIndex(index))
+            {
+                auto it = pageTable.find(index);
+                if (it != pageTable.end())
+                {
+                    return it->second;
+                }
+                else
+                {
+                    throw std::out_of_range("Index not found in the page table");
+                }
+            }
+            else
+            {
+                throw std::out_of_range("Invalid index");
+            }
+        }
+
+        void removeEntry(uint32_t index)
+        {
+            if (isValidIndex(index))
+            {
+                auto it = pageTable.find(index);
+                if (it != pageTable.end())
+                {
+                    pageTable.erase(it);
+                }
+                else
+                {
+                    throw std::out_of_range("Index not found in the page table");
+                }
+            }
+            else
+            {
+                throw std::out_of_range("Invalid index");
+            }
+        }
+
+        bool contains(uint32_t index) const { return pageTable.find(index) != pageTable.end(); }
+
+        void print(std::ostream & os) const
+        {
+            for (const auto & [index, entry] : pageTable)
+            {
+                os << "Index: " << index << " | PTE: " << entry.getPTE() << std::endl;
+            }
+        }
     };
 
-    template <MMUMode Mode>
-    std::ostream & operator<<(std::ostream & os, const PageTable<Mode> & pt);
+    template <MMUMode Mode> std::ostream & operator<<(std::ostream & os, const PageTable<Mode> & pt)
+    {
+        pt.print(os);
+        return os;
+    }
 } // namespace atlas
-
-#include "PageTable.tpp"