CPU: Basic recompiler implementation for x64 (lui, ori, addiu)

Disabled by default.

src/core/cpu_code_cache.h

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+#pragma once
+#include "common/bitfield.h"
+#include "cpu_types.h"
+#include <array>
+#include <memory>
+#include <unordered_map>
+#include <vector>
+
+class JitCodeBuffer;
+
+class Bus;
+
+namespace CPU {
+class Core;
+
+namespace Recompiler {
+class ASMFunctions;
+}
+
+class CodeCache
+{
+public:
+  CodeCache();
+  ~CodeCache();
+
+  void Initialize(Core* core, Bus* bus);
+  void Reset();
+  void Execute();
+
+  /// Flushes all blocks which are in the range of the specified code page.
+  void FlushBlocksWithPageIndex(u32 page_index);
+
+private:
+  using BlockMap = std::unordered_map<u32, CodeBlock*>;
+
+  const CodeBlock* GetNextBlock();
+  bool CompileBlock(CodeBlock* block);
+  void FlushBlock(CodeBlock* block);
+  void InterpretCachedBlock(const CodeBlock& block);
+  void InterpretUncachedBlock();
+
+  Core* m_core;
+  Bus* m_bus;
+
+  const CodeBlock* m_current_block = nullptr;
+  bool m_current_block_flushed = false;
+
+  std::unique_ptr<JitCodeBuffer> m_code_buffer;
+  std::unique_ptr<Recompiler::ASMFunctions> m_asm_functions;
+
+  BlockMap m_blocks;
+
+  std::array<std::vector<CodeBlock*>, CPU_CODE_CACHE_PAGE_COUNT> m_ram_block_map;
+};
+
+extern bool USE_CODE_CACHE;
+extern bool USE_RECOMPILER;
+
+} // namespace CPU