diff --git a/simulator_SIC_XE/include/file_reader.h b/simulator_SIC_XE/include/file_reader.h
new file mode 100644
index 0000000..2ee9fcd
--- /dev/null
+++ b/simulator_SIC_XE/include/file_reader.h
@@ -0,0 +1,19 @@
+#pragma once
+#include "reader.h"
+#include <string>
+#include <fstream>
+
+class FileReader : public Reader {
+public:
+    explicit FileReader(const std::string &path, std::ios::openmode m = std::ios::binary);
+    ~FileReader() override;
+
+    int readByte() override;
+    bool readBytes(uint8_t* buf, size_t len) override;
+    std::string readString(size_t len) override;
+
+    bool good() const;
+
+private:
+    std::ifstream in;
+};
diff --git a/simulator_SIC_XE/include/reader.h b/simulator_SIC_XE/include/reader.h
new file mode 100644
index 0000000..ff64e77
--- /dev/null
+++ b/simulator_SIC_XE/include/reader.h
@@ -0,0 +1,15 @@
+#pragma once
+#include <string>
+#include <cstdint>
+
+// Abstract Reader class: read bytes/strings from a source (file, string, etc.)
+class Reader {
+public:
+    virtual ~Reader() = default;
+    // return 0..255 on success, -1 on EOF/error
+    virtual int readByte() = 0;
+    // read exactly len bytes into buf; return true on success
+    virtual bool readBytes(uint8_t* buf, size_t len) = 0;
+    // read up to len bytes into a std::string; may return shorter string on EOF
+    virtual std::string readString(size_t len) = 0;
+};
\ No newline at end of file
diff --git a/simulator_SIC_XE/include/string_reader.h b/simulator_SIC_XE/include/string_reader.h
new file mode 100644
index 0000000..6b9187e
--- /dev/null
+++ b/simulator_SIC_XE/include/string_reader.h
@@ -0,0 +1,17 @@
+#pragma once
+#include "reader.h"
+#include <string>
+#include <sstream>
+
+class StringReader : public Reader {
+public:
+    explicit StringReader(const std::string &s);
+    ~StringReader() override;
+
+    int readByte() override;
+    bool readBytes(uint8_t* buf, size_t len) override;
+    std::string readString(size_t len) override;
+
+private:
+    std::istringstream in;
+};
diff --git a/simulator_SIC_XE/src/file_reader.cpp b/simulator_SIC_XE/src/file_reader.cpp
new file mode 100644
index 0000000..5785f06
--- /dev/null
+++ b/simulator_SIC_XE/src/file_reader.cpp
@@ -0,0 +1,29 @@
+#include "file_reader.h"
+
+FileReader::FileReader(const std::string &path, std::ios::openmode m)
+    : in(path, m)
+{}
+
+FileReader::~FileReader() = default;
+
+int FileReader::readByte() {
+    char c;
+    if (!in.get(c)) return -1;
+    return static_cast<unsigned char>(c);
+}
+
+bool FileReader::readBytes(uint8_t* buf, size_t len) {
+    in.read(reinterpret_cast<char*>(buf), static_cast<std::streamsize>(len));
+    return static_cast<size_t>(in.gcount()) == len;
+}
+
+std::string FileReader::readString(size_t len) {
+    std::string s;
+    s.resize(len);
+    in.read(reinterpret_cast<char*>(&s[0]), static_cast<std::streamsize>(len));
+    std::streamsize got = in.gcount();
+    if (static_cast<size_t>(got) < len) s.resize(static_cast<size_t>(got));
+    return s;
+}
+
+bool FileReader::good() const { return static_cast<bool>(in); }
diff --git a/simulator_SIC_XE/src/string_reader.cpp b/simulator_SIC_XE/src/string_reader.cpp
new file mode 100644
index 0000000..3a24cb9
--- /dev/null
+++ b/simulator_SIC_XE/src/string_reader.cpp
@@ -0,0 +1,27 @@
+#include "string_reader.h"
+
+StringReader::StringReader(const std::string &s)
+    : in(s)
+{}
+
+StringReader::~StringReader() = default;
+
+int StringReader::readByte() {
+    char c;
+    if (!in.get(c)) return -1;
+    return static_cast<unsigned char>(c);
+}
+
+bool StringReader::readBytes(uint8_t* buf, size_t len) {
+    in.read(reinterpret_cast<char*>(buf), static_cast<std::streamsize>(len));
+    return static_cast<size_t>(in.gcount()) == len;
+}
+
+std::string StringReader::readString(size_t len) {
+    std::string s;
+    s.resize(len);
+    in.read(reinterpret_cast<char*>(&s[0]), static_cast<std::streamsize>(len));
+    std::streamsize got = in.gcount();
+    if (static_cast<size_t>(got) < len) s.resize(static_cast<size_t>(got));
+    return s;
+}