From ca0bcdeda4bbe51b3f628053cc2471749aaad91e Mon Sep 17 00:00:00 2001
From: Nav <nav@navnav.me>
Date: Tue, 28 Dec 2021 00:00:45 +0000
Subject: [PATCH] GDB register descriptor

---
 .../GdbRsp/AvrGdbRsp/AvrGdbRsp.hpp            |  2 +-
 .../GdbRsp/CommandPackets/ReadRegisters.hpp   |  4 +-
 src/DebugServers/GdbRsp/GdbRspDebugServer.hpp |  2 +-
 src/DebugServers/GdbRsp/Register.hpp          |  6 --
 .../GdbRsp/RegisterDescriptor.hpp             | 67 +++++++++++++++++++
 5 files changed, 72 insertions(+), 9 deletions(-)
 delete mode 100644 src/DebugServers/GdbRsp/Register.hpp
 create mode 100644 src/DebugServers/GdbRsp/RegisterDescriptor.hpp

diff --git a/src/DebugServers/GdbRsp/AvrGdbRsp/AvrGdbRsp.hpp b/src/DebugServers/GdbRsp/AvrGdbRsp/AvrGdbRsp.hpp
index 63342b52..41477a5c 100644
--- a/src/DebugServers/GdbRsp/AvrGdbRsp/AvrGdbRsp.hpp
+++ b/src/DebugServers/GdbRsp/AvrGdbRsp/AvrGdbRsp.hpp
@@ -3,7 +3,7 @@
 #include <cstdint>
 
 #include "src/DebugServers/GdbRsp/GdbRspDebugServer.hpp"
-#include "src/DebugServers/GdbRsp/Register.hpp"
+#include "src/DebugServers/GdbRsp/RegisterDescriptor.hpp"
 #include "src/Helpers/BiMap.hpp"
 
 namespace Bloom::DebugServers::Gdb
diff --git a/src/DebugServers/GdbRsp/CommandPackets/ReadRegisters.hpp b/src/DebugServers/GdbRsp/CommandPackets/ReadRegisters.hpp
index 20055bbe..539d8215 100644
--- a/src/DebugServers/GdbRsp/CommandPackets/ReadRegisters.hpp
+++ b/src/DebugServers/GdbRsp/CommandPackets/ReadRegisters.hpp
@@ -4,6 +4,8 @@
 
 #include "CommandPacket.hpp"
 
+#include "src/DebugServers/GdbRsp/RegisterDescriptor.hpp"
+
 namespace Bloom::DebugServers::Gdb::CommandPackets
 {
     /**
@@ -21,7 +23,7 @@ namespace Bloom::DebugServers::Gdb::CommandPackets
          * If the register number is not supplied (as is the case with "g" packets), the server is expected to respond
          * with values for all registers.
          */
-        std::optional<int> registerNumber;
+        std::optional<GdbRegisterNumberType> registerNumber;
 
         explicit ReadRegisters(const std::vector<unsigned char>& rawPacket): CommandPacket(rawPacket) {
             init();
diff --git a/src/DebugServers/GdbRsp/GdbRspDebugServer.hpp b/src/DebugServers/GdbRsp/GdbRspDebugServer.hpp
index 95fe2a47..b961f143 100644
--- a/src/DebugServers/GdbRsp/GdbRspDebugServer.hpp
+++ b/src/DebugServers/GdbRsp/GdbRspDebugServer.hpp
@@ -9,7 +9,7 @@
 #include "../DebugServer.hpp"
 #include "Connection.hpp"
 #include "Signal.hpp"
-#include "Register.hpp"
+#include "RegisterDescriptor.hpp"
 #include "Feature.hpp"
 #include "src/Helpers/EventNotifier.hpp"
 #include "src/Helpers/BiMap.hpp"
diff --git a/src/DebugServers/GdbRsp/Register.hpp b/src/DebugServers/GdbRsp/Register.hpp
deleted file mode 100644
index 98220c1e..00000000
--- a/src/DebugServers/GdbRsp/Register.hpp
+++ /dev/null
@@ -1,6 +0,0 @@
-#pragma once
-
-namespace Bloom::DebugServers::Gdb
-{
-    using GdbRegisterNumber = int;
-}
diff --git a/src/DebugServers/GdbRsp/RegisterDescriptor.hpp b/src/DebugServers/GdbRsp/RegisterDescriptor.hpp
new file mode 100644
index 00000000..e6675efd
--- /dev/null
+++ b/src/DebugServers/GdbRsp/RegisterDescriptor.hpp
@@ -0,0 +1,67 @@
+#pragma once
+
+#include <cstdint>
+#include <string>
+
+namespace Bloom::DebugServers::Gdb
+{
+    using GdbRegisterNumberType = int;
+
+    /*
+     * GDB defines a set of registers for each target architecture.
+     *
+     * Each register in the set is assigned a register number, which is used to identify the register.
+     */
+    struct RegisterDescriptor
+    {
+        GdbRegisterNumberType number;
+        std::uint16_t size;
+        std::string name;
+
+        RegisterDescriptor(GdbRegisterNumberType number, std::uint16_t size, const std::string& name)
+        : number(number), size(size), name(name) {};
+
+        bool operator == (const RegisterDescriptor& other) const {
+            return this->number == other.number;
+        }
+
+        bool operator != (const RegisterDescriptor& other) const {
+            return !(*this == other);
+        }
+
+        bool operator < (const RegisterDescriptor& rhs) const {
+            return this->number < rhs.number;
+        }
+
+        bool operator > (const RegisterDescriptor& rhs) const {
+            return rhs < *this;
+        }
+
+        bool operator <= (const RegisterDescriptor& rhs) const {
+            return !(rhs < *this);
+        }
+
+        bool operator >= (const RegisterDescriptor& rhs) const {
+            return !(*this < rhs);
+        }
+    };
+}
+
+namespace std
+{
+    /**
+     * Hashing function for RegisterDescriptor type.
+     *
+     * This is required in order to use RegisterDescriptor as a key in an std::unordered_map (see the BiMap
+     * class).
+     */
+    template<>
+    class hash<Bloom::DebugServers::Gdb::RegisterDescriptor>
+    {
+    public:
+        std::size_t operator () (const Bloom::DebugServers::Gdb::RegisterDescriptor& descriptor) const {
+            // We use the GDB register number as the hash, as it is unique to the register.
+            return static_cast<size_t>(descriptor.number);
+        }
+    };
+}