added M records

simulator_SIC_XE/include/code.h

@@ -36,6 +36,12 @@ private:
     int _programLength = 0;
     std::string _programName;
     int _baseRegister = -1;  // -1 means not set
+    
+    struct ModificationRecord {
+        int address;    
+        int halfBytes;  
+    };
+    mutable std::vector<ModificationRecord> _modificationRecords;
 
     // Pass 1: build symbol table and assign addresses
     void firstPass();

simulator_SIC_XE/include/loader.h

@@ -27,6 +27,7 @@ public:
     enum class RecordType {
         HEADER,
         TEXT,
+        MODIFICATION,
         END,
         UNKNOWN
     };
@@ -40,6 +41,11 @@ public:
         int start_address;
         std::vector<uint8_t> data;
     };
+    struct ModificationRecord {
+        int address;        // Address to be modified
+        int length;         // Length in nibbles
+        bool add;           // true for +, false for -
+    };
     struct EndRecord {
         int execution_start_address;
     };
@@ -54,10 +60,13 @@ private :
     shared_ptr<Machine> _machine;
     string _filename;
     shared_ptr<FileReader> _file_reader;
+    int _relocation_address;
     HeaderMetadata readHeader();
     TextRecord readTextRecord();
+    ModificationRecord readModificationRecord();
     EndRecord readEndRecord();
     bool load_into_memory(int start_address, const std::vector<uint8_t>& data);
+    void applyModification(const ModificationRecord& mod);
 
 };
 

simulator_SIC_XE/include/opcode.h

@@ -6,6 +6,7 @@
 #include <unordered_map>
 #include <string_view>
 #include <optional>
+#include <cstdint>
 
 // ==============================
 // Opcode definitions (SIC/XE)