Add DSP emulation interface

Co-Authored-By: PSISP <12768103+psi-rockin@users.noreply.github.com>

include/audio/null_core.hpp

@@ -0,0 +1,41 @@
+#pragma once
+#include <array>
+#include "audio/dsp_core.hpp"
+
+namespace Audio {
+	class NullDSP : public DSPCore {
+		enum class DSPState : u32 {
+			Off,
+			On,
+			Slep,
+		};
+
+		// Number of DSP pipes
+		static constexpr size_t pipeCount = 8;
+		DSPState dspState;
+
+		std::array<std::vector<u8>, pipeCount> pipeData;  // The data of each pipe
+		std::array<u8, Memory::DSP_RAM_SIZE> dspRam;
+
+		void resetAudioPipe();
+
+	  public:
+		NullDSP(Memory& mem) : DSPCore(mem) {}
+
+		void reset() override;
+		void runAudioFrame() override {}
+		u8* getDspMemory() override { return dspRam.data(); }
+
+		u16 recvData(u32 regId) override;
+		bool recvDataIsReady(u32 regId) override { return true; } // Treat data as always ready
+		void writeProcessPipe(u32 channel, u32 size, u32 buffer) override;
+		std::vector<u8> readPipe(u32 channel, u32 peer, u32 size, u32 buffer) override;
+
+		// NOPs for null DSP core
+		void loadComponent(std::vector<u8>& data, u32 programMask, u32 dataMask) override {}
+		void unloadComponent() override {}
+		void setSemaphore(u16 value) override {}
+		void setSemaphoreMask(u16 value) override {}
+	};
+
+}  // namespace Audio