Emulator: Add opcode lookup table

src/cpu.cpp

@@ -8,6 +8,7 @@
 #include <cstdint> // uint8_t, uint32_t
 
 #include "cpu.h"
+#include "emu.h"
 #include "ruc/format/print.h"
 #include "ruc/meta/assert.h"
 
@@ -22,7 +23,8 @@ CPU::CPU(uint32_t frequency)
 	, m_e(0x56)
 	, m_h(0x0)
 	, m_l(0x0d)
-	, m_pc(0x100)
+	// , m_pc(0x100)
+	, m_pc(0x0)
 	, m_sp(0xffe)
 	// Flags
 	, m_zf(0x1)
@@ -43,6 +45,12 @@ CPU::CPU(uint32_t frequency)
 	m_shared_registers.emplace("nf", &m_nf);
 	m_shared_registers.emplace("hf", &m_hf);
 	m_shared_registers.emplace("cf", &m_cf);
+
+	// Add opcode functions to lookup table
+	m_opcode_lookup_table.emplace(0x08, std::bind(&CPU::ldStack, this));
+	m_opcode_lookup_table.emplace(0x31, std::bind(&CPU::ldStack, this));
+	m_opcode_lookup_table.emplace(0xf8, std::bind(&CPU::ldStack, this));
+	m_opcode_lookup_table.emplace(0xf9, std::bind(&CPU::ldStack, this));
 }
 
 CPU::~CPU()
@@ -54,6 +62,8 @@ void CPU::update()
 	m_wait_cycles--;
 	if (m_wait_cycles <= 0) {
 		// Read next opcode
+		uint8_t opcode = Emu::the().bootrom()[m_pc];
+		m_opcode_lookup_table[opcode]();
 	}
 
 	// print("This is an update from the CPU\n");
@@ -83,6 +93,24 @@ void CPU::add(uint8_t opcode, uint8_t immediate)
 		break;
 	default:
 		VERIFY_NOT_REACHED();
-		break;
+	}
+}
+
+void CPU::ldStack()
+{
+	printf("Calling stack LD\n");
+
+	uint8_t opcode = Emu::the().bootrom()[m_pc];
+	switch (opcode) {
+	case 0x08:
+		break;
+	case 0x31:
+		break;
+	case 0xf8:
+		break;
+	case 0xf9:
+		break;
+	default:
+		VERIFY_NOT_REACHED();
 	}
 }

src/cpu.h

@@ -7,7 +7,9 @@
 
 #pragma once
 
-#include <cstdint> // int8_t, uint8_t, uint32_t
+#include <cstdint>    // int8_t, uint8_t, uint32_t
+#include <functional> // function
+#include <unordered_map>
 
 #include "processing-unit.h"
 
@@ -34,6 +36,8 @@ public:
 
 	// Stack Operations Instructions
 
+	void ldStack();
+
 	// Miscellaneous Instructions
 
 private:
@@ -55,4 +59,6 @@ private:
 	uint32_t m_cf { 0 }; // Carry flag
 
 	int8_t m_wait_cycles { 0 };
+
+	std::unordered_map<uint32_t, std::function<void()>> m_opcode_lookup_table;
 };

src/emu.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <cstdint> // uint32_t
+#include <string>
 #include <string_view>
 #include <unordered_map>
 #include <vector>
@@ -27,6 +28,8 @@ public:
 
 	ProcessingUnit* processingUnit(std::string_view name) const { return m_processing_units.at(name); }
 
+	std::string_view bootrom() const { return m_bootrom; }
+
 private:
 	uint32_t m_frequency { 0 };
 	double m_timestep { 0 };
@@ -39,5 +42,5 @@ private:
 	std::unordered_map<std::string_view, ProcessingUnit*> m_processing_units;
 	std::unordered_map<std::string_view, std::vector<uint32_t>> m_memory_spaces;
 
-	std::string_view m_bootrom;
+	std::string m_bootrom;
 };