Initial GIF implementation

Currently there's nothing really of note, it's just an empty
class that handles reads/writes to some of the registers. The
functionality will be explained in subsequent commits. Along with
this I've added a new document, from which, the GIF implementation will
be based on.

CMakeLists.txt

@@ -19,6 +19,7 @@ add_executable(${PROJECT_NAME}
 	"src/cpu/iop/timers.cc" 
 	"src/cpu/ee/intc.cc"
 	"src/cpu/iop/intr.cc"
+	"src/gs/gif.cc"
 )
 
 # Link to all the required conan libs

src/common/emulator.cc

 #include <common/emulator.h>
 #include <cpu/ee/ee.h>
 #include <cpu/iop/iop.h>
+#include <gs/gif.h>
 #include <cassert>
 
 int cycles_executed = 0;
@@ -20,6 +21,7 @@ namespace common
         ee = std::make_unique<ee::EmotionEngine>(this);
         iop = std::make_unique<iop::IOProcessor>(this);
         iop_dma = std::make_unique<iop::DMAController>(this);
+        gif = std::make_unique<gs::GIF>(this);
     }
 
     Emulator::~Emulator()

src/common/emulator.h

@@ -15,6 +15,11 @@ namespace iop
     class IOProcessor;
 }
 
+namespace gs
+{
+    struct GIF;
+}
+
 namespace common
 {
     constexpr uint32_t KUSEG_MASKS[8] = 
@@ -64,9 +69,10 @@ namespace common
         std::unique_ptr<ee::EmotionEngine> ee;
         std::unique_ptr<iop::IOProcessor> iop;
         std::unique_ptr<iop::DMAController> iop_dma;
+        std::unique_ptr<gs::GIF> gif;
 
         /* Memory - Registers */
-        uint8_t * bios;
+        uint8_t* bios;
 
         uint32_t MCH_RICM = 0, MCH_DRD = 0;
         uint8_t rdram_sdevid = 0;

src/gs/gif.cc

+#include <gs/gif.h>
+#include <common/emulator.h>
+#include <cassert>
+#include <fmt/core.h>
+
+static const char* REGS[10] =
+{
+	"GIF_CTRL",
+	"GIF_MODE",
+	"GIF_STAT",
+	"GIF_TAG0",
+	"GIF_TAG1",
+	"GIF_TAG2",
+	"GIF_TAG3",
+	"GIF_CNT",
+	"GIF_P3CNT",
+	"GIF_P3TAG"
+};
+
+namespace gs
+{
+	GIF::GIF(common::Emulator* parent) :
+		emulator(parent)
+	{
+		uint32_t PAGE1 = common::Emulator::calculate_page(0x10003000);
+		emulator->add_handler(PAGE1, this, &GIF::read, &GIF::write);
+	}
+	
+	uint64_t GIF::read(uint32_t addr)
+	{
+		assert(addr <= 0x100030A0);
+
+		uint32_t offset = (addr & 0xf0) >> 4;
+		auto ptr = (uint32_t*)&regs + offset;
+
+		fmt::print("[GIF] Read {:#x} from {}\n", *ptr, REGS[offset]);
+
+		return *ptr;
+	}
+	
+	void GIF::write(uint32_t addr, uint64_t data)
+	{
+		assert(addr <= 0x100030A0);
+
+		uint32_t offset = (addr & 0xf0) >> 4;
+		auto ptr = (uint32_t*)&regs + offset;
+
+		fmt::print("[GIF] Write {:#x} to {}\n", data, REGS[offset]);
+
+		*ptr = data;
+	}
+}
\ No newline at end of file

src/gs/gif.h

+#pragma once
+#include <common/component.h>
+
+namespace common
+{
+	class Emulator;
+}
+
+namespace gs
+{
+	union GIFSTAT
+	{
+		uint32_t value;
+		struct
+		{
+			uint32_t M3R : 1;
+			uint32_t M3P : 1;
+			uint32_t IMT : 1;
+			uint32_t PSE : 1;
+			uint32_t IP3 : 1;
+			uint32_t P3Q : 1;
+			uint32_t P2Q : 1;
+			uint32_t P1Q : 1;
+			uint32_t OPH : 1;
+			uint32_t APATH : 2;
+			uint32_t DIR : 1;
+			uint32_t : 12;
+			uint32_t FQC : 5;
+			uint32_t : 3;
+		};
+	};
+
+	struct GIFRegs
+	{
+		uint32_t GIF_CTRL;
+		uint32_t GIF_MODE;
+		GIFSTAT GIF_STAT;
+		uint32_t GIF_TAG0;
+		uint32_t GIF_TAG1;
+		uint32_t GIF_TAG2;
+		uint32_t GIF_TAG3;
+		uint32_t GIF_CNT;
+		uint32_t GIF_P3CNT;
+		uint32_t GIF_P3TAG;
+	};
+
+	struct GIF : public common::Component
+	{
+		GIF(common::Emulator* parent);
+		
+		uint64_t read(uint32_t addr);
+		void write(uint32_t addr, uint64_t data);
+
+	private:
+		common::Emulator* emulator;
+		GIFRegs regs = {};
+	};
+}
\ No newline at end of file

src/gs/gs.h

+#pragma once
+#include <common/component.h>
+
+namespace gs
+{
+	/* These can be accessed from the EE */
+	struct PrivRegs
+	{
+		uint64_t PMODE;
+		uint64_t SMODE1;
+		uint64_t SMODE2;
+		uint64_t SRFSH;
+		uint64_t SYNCH1;
+		uint64_t SYNCH2;
+		uint64_t SYNCV;
+		uint64_t DISPFB1;
+		uint64_t DISPLAY1;
+		uint64_t DISPFB2;
+		uint64_t DISPLAY2;
+		uint64_t EXTBUF;
+		uint64_t EXTDATA;
+		uint64_t EXTWRITE;
+		uint64_t BGCOLOR;
+		uint64_t GS_CSR;
+		uint64_t GS_IMR;
+		uint64_t BUSDIR;
+		uint64_t SIGLBLID;
+	};
+
+	class GS : public common::Component
+	{
+
+	};
+}
\ No newline at end of file