Implemented CPU, with few instructions.

subratkatiyar · May 17, 2024 · fee4c1a · fee4c1a
1 parent caa91df
commit fee4c1a
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Showing 17 changed files with 536 additions and 50 deletions.
diff --git a/Gameboy/COMPARE.cpp b/Gameboy/COMPARE.cpp
@@ -0,0 +1,18 @@
+#include "CPU.h"
+#include <iomanip>
+#include <iostream>
+
+void CPU::execute_CP_n(){
+	MemoryUnitObj->registers.pc++;
+	uint8_t n = MemoryUnitObj->read_memory(MemoryUnitObj->registers.pc);
+	uint8_t result = MemoryUnitObj->registers.a - n;
+
+	MemoryUnitObj->set_flag(FLAG_Z, MemoryUnitObj->registers.c == 0);
+	MemoryUnitObj->set_flag(FLAG_N, 1);
+	MemoryUnitObj->checknset_halfcarry_flag(result);
+	MemoryUnitObj->set_flag(FLAG_C, MemoryUnitObj->registers.a < n);
+	MemoryUnitObj->registers.pc++;
+
+	std::cout << "cp a," << std::setw(2) << std::setfill('0') << std::hex << static_cast<int>(n) << "\n";
+
+}
diff --git a/Gameboy/CPU.cpp b/Gameboy/CPU.cpp
@@ -0,0 +1,143 @@
+#include "CPU.h"
+#include "iostream"
+#include <iomanip>
+#include <cassert>
+
+void CPU::executeNOP()
+{
+	std::cout << "nop\n";
+	MemoryUnitObj->registers.pc++;
+}
+
+void CPU::execute_XOR_A() {
+	// XOR A
+	MemoryUnitObj->registers.a ^= MemoryUnitObj->registers.a;
+
+	// Update flags
+	MemoryUnitObj->set_flag(FLAG_Z, MemoryUnitObj->registers.a == 0);
+	MemoryUnitObj->set_flag(FLAG_N, 0);
+	MemoryUnitObj->set_flag(FLAG_H, 0);
+	MemoryUnitObj->set_flag(FLAG_C, 0);
+
+	//Update PC
+	MemoryUnitObj->registers.pc++;
+
+	std::cout << "XOR A\n";
+}
+
+void CPU::execute_HL_nn() {
+	MemoryUnitObj->registers.pc++;
+	uint16_t nn = MemoryUnitObj->read_memory_16_le(MemoryUnitObj->registers.pc);
+	MemoryUnitObj->registers.hl = nn;
+	MemoryUnitObj->registers.pc += 2;
+	std::cout << "ld hl " << std::setw(4) << std::setfill('0') << std::hex << nn << "\n";
+
+}
+
+CPU::CPU(MemoryUnit *memoryUnitPointer)
+{
+	MemoryUnitObj = memoryUnitPointer;
+	initialize_memory();
+	initialize_registers();
+	MemoryUnitObj->load_rom("..\\roms\\Tetris.gb");
+}
+
+void CPU::initialize_memory()
+{
+	MemoryUnitObj->load_vram("..\\roms\\VRAM.dump");
+	MemoryUnitObj->reset_eram();
+	MemoryUnitObj->reset_notusuable();
+	MemoryUnitObj->load_ioregisters("..\\roms\\IO.dump");
+	MemoryUnitObj->reset_ieregister();
+}
+
+void CPU::initialize_registers()
+{
+	MemoryUnitObj->registers.af = 0x01B0;  // Example: Set flags (Z=0, N=1, H=1, C=0)
+	MemoryUnitObj->registers.bc = 0x0013;  // Example: Set BC register pair
+	MemoryUnitObj->registers.de = 0x00D8;  // Example: Set DE register pair
+	MemoryUnitObj->registers.hl = 0x014D;  // Example: Set HL register pair
+	MemoryUnitObj->registers.sp = 0xFFFE;  // Example: Set Stack Pointer
+	MemoryUnitObj->registers.pc = 0x0100;  // Example: Set Program Counter
+}
+
+void CPU::debug_registers() {
+	std::cout << "AF = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.af << " ";
+	std::cout << "BC = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.bc << " ";
+	std::cout << "DE = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.de << " ";
+	std::cout << "HL = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.hl << " ";
+	std::cout << "SP = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.sp << " ";
+	std::cout << "PC = 0x" << std::setw(4) << std::setfill('0') << std::hex << MemoryUnitObj->registers.pc << " ";
+	std::cout << "INS = 0x" << std::setw(2) << std::setfill('0') << std::hex << static_cast<int>(MemoryUnitObj->read_memory(MemoryUnitObj->registers.pc)) << "\n";
+}
+
+void CPU::execute_unimplemented() {
+	// Print an error message
+	std::cout<<"Error: Instruction not implemented\n";
+	assert(0); // This will cause the program to terminate with an error message
+}
+
+void CPU::start_execution()
+{
+	while (true) {
+		debug_registers();
+		uint8_t opcode = MemoryUnitObj->read_memory(MemoryUnitObj->registers.pc);
+		switch (opcode) {
+			case 0x00:
+				executeNOP();
+				break;
+			case 0x05:
+				execute_DEC_B();
+				break;
+			case 0x06:
+				execute_LD_B_n();
+				break;
+			case 0x0D:
+				execute_DEC_C();
+				break;
+			case 0x0E:
+				execute_LD_C_n();
+				break;
+			case 0x20:
+				execute_JR_NZ_n();
+				break;
+			case 0x21:
+				execute_HL_nn();
+				break;
+			case 0x32:
+				execute_LD_HL_dec_A();
+				break;
+			case 0x36:
+				execute_LD_HL_n();
+				break;
+			case 0x3E:
+				execute_LD_A_n();
+				break;
+			case 0xAF:
+				execute_XOR_A();
+				break;
+			case 0xC3:
+				execute_JP_nn();
+				break;
+			case 0xE0:
+				execute_LDH_n_A();
+				break;
+			case 0xEA:
+				execute_LD_nn_A();
+				break;
+			case 0xF0:
+				execute_LDH_A_n();
+				break;
+			case 0xF3:
+				execute_DI();
+				break;
+			case 0xFE:
+				execute_CP_n();
+				break;
+			default:
+//				debug_registers();
+				execute_unimplemented();
+				break;
+		}
+	}
+}
diff --git a/Gameboy/CPU.h b/Gameboy/CPU.h
@@ -0,0 +1,41 @@
+#pragma once
+#include "MemoryUnit.h"
+
+class CPU {
+private:
+	void executeNOP();
+	void execute_JP_nn();
+	void execute_XOR_A();
+	void execute_HL_nn();
+	void execute_LD_A_n();
+	void execute_LD_nn_A();
+	void execute_LDH_n_A();
+	void execute_LD_HL_n();
+	void execute_LDH_A_n();
+	void execute_LD_B_n();
+	void execute_LD_C_n();
+	void execute_LD_HL_dec_A();
+	void execute_DEC_B();
+	void execute_DEC_C();
+	void execute_JR_NZ_n();
+	void execute_DI();
+	void execute_CP_n();
+public:
+	MemoryUnit *MemoryUnitObj;
+	CPU(MemoryUnit*);
+	void initialize_memory();
+	void initialize_registers();
+	void start_execution();
+	void debug_registers();
+
+	void execute_unimplemented();
+
+
+
+
+
+
+
+
+
+};
diff --git a/Gameboy/DECREASE.cpp b/Gameboy/DECREASE.cpp
@@ -0,0 +1,23 @@
+#include "CPU.h"
+#include <iomanip>
+#include <iostream>
+
+void CPU::execute_DEC_B() {
+	MemoryUnitObj->registers.pc++;
+	MemoryUnitObj->registers.b--;
+
+	MemoryUnitObj->set_flag(FLAG_Z, MemoryUnitObj->registers.b == 0);
+	MemoryUnitObj->set_flag(FLAG_N, 1);
+	MemoryUnitObj->checknset_halfcarry_flag(MemoryUnitObj->registers.b);
+	std::cout << "dec b\n";
+}
+
+void CPU::execute_DEC_C() {
+	MemoryUnitObj->registers.pc++;
+	MemoryUnitObj->registers.c--;
+
+	MemoryUnitObj->set_flag(FLAG_Z, MemoryUnitObj->registers.c == 0);
+	MemoryUnitObj->set_flag(FLAG_N, 1);
+	MemoryUnitObj->checknset_halfcarry_flag(MemoryUnitObj->registers.c);
+	std::cout << "dec c\n";
+}
diff --git a/Gameboy/DisassemblyView.cpp b/Gameboy/DisassemblyView.cpp
@@ -12,11 +12,11 @@ std::string DisassemblyView::ByteToHexString(uint8_t byte)
     return stream.str();
 }
 
-DisassemblyView::DisassemblyView(GameboyMemory* memoryPointer)
+DisassemblyView::DisassemblyView(MemoryUnit *memoryPointer)
 {
 	// Name your application
 	sAppName = "Disassembly View";
-    memory = memoryPointer;
+    memory = &memoryPointer->memory;
 }
 
 void DisassemblyView::DrawMemory()
@@ -41,7 +41,7 @@ void DisassemblyView::DrawMemory()
             if (i + j >= sizeof(GameboyMemory)) break;
 
             // Draw byte value
-            std::string byteStr = ByteToHexString(*((uint8_t*)memory + i + j));
+            std::string byteStr = ByteToHexString(*((uint8_t*)&memory + i + j));
             DrawString(50 + j * 3 * 5 + j * 3, yPos, byteStr, olc::WHITE);
             DrawString(50 + j * 3 * 5 + j * 3 + 10, yPos, " ", olc::WHITE);
 

diff --git a/Gameboy/DisassemblyView.h b/Gameboy/DisassemblyView.h
@@ -14,8 +14,8 @@ class DisassemblyView : public olc::PixelGameEngine
 		void DrawMemory();
 		std::string ByteToHexString(uint8_t);
 	public:
-		GameboyMemory* memory;
-		DisassemblyView(GameboyMemory*);
+		GameboyMemory *memory;
+		DisassemblyView(MemoryUnit*);
 		bool OnUserCreate() override;
 		bool OnUserUpdate(float fElapsedTime) override;
 };
diff --git a/Gameboy/DisplayUnit.cpp b/Gameboy/DisplayUnit.cpp
@@ -29,8 +29,8 @@ void DisplayUnit::DrawTile(int tile_idx) // Function used for TileMap Only.
 	int tile_xPos = tile_idx % 16;
 	int tile_yPos = tile_idx / 16;
 
-	int memoryStart = (256 * tile_yPos) + (tile_xPos * 16);
-	int memoryEnd = memoryStart + 16;
+	uint32_t memoryStart = (256 * tile_yPos) + (tile_xPos * 16);
+	uint32_t memoryEnd = memoryStart + 16;
 
 	//std::cout << tile_idx << "->" << memoryStart << " " << memoryEnd << "\n";
 	for (uint32_t addr = memoryStart; addr < memoryEnd; addr += 0x02) {
@@ -67,8 +67,8 @@ void DisplayUnit::DrawTile(uint8_t tile_idx, int tile_xPos, int tile_yPos)
 	std::pair<int32_t, int32_t> RectangleDimensions = { ScreenWidth(), ScreenHeight() };
 	std::pair<int32_t, int32_t> pixelSize = { RectangleDimensions.first / 256, RectangleDimensions.second / 192 };
 
-	int memoryStart = (256 * (tile_idx / 16)) + ((tile_idx % 16) * 16);
-	int memoryEnd = memoryStart + 16;
+	uint32_t memoryStart = (256 * (tile_idx / 16)) + ((tile_idx % 16) * 16);
+	uint32_t memoryEnd = memoryStart + 16;
 
 	//std::cout << tile_idx << "->" << memoryStart << " " << memoryEnd << "\n";
 	for (uint32_t addr = memoryStart; addr < memoryEnd; addr += 0x02) {

diff --git a/Gameboy/Gameboy.vcxproj b/Gameboy/Gameboy.vcxproj
@@ -127,25 +127,29 @@
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClInclude Include="CPU.h" />
     <ClInclude Include="DisassemblyView.h" />
     <ClInclude Include="DisplayUnit.h" />
     <ClInclude Include="MemoryUnit.h" />
     <ClInclude Include="olcPixelGameEngine.h" />
   </ItemGroup>
   <ItemGroup>
+    <ClCompile Include="COMPARE.cpp" />
+    <ClCompile Include="CPU.cpp" />
+    <ClCompile Include="DECREASE.cpp" />
     <ClCompile Include="DisassemblyView.cpp" />
     <ClCompile Include="DisplayUnit.cpp" />
+    <ClCompile Include="JUMP.cpp" />
+    <ClCompile Include="LOAD.cpp" />
     <ClCompile Include="main.cpp" />
     <ClCompile Include="MemoryUnit.cpp" />
     <ClCompile Include="olcPixelGameEngine.cpp" />
+    <ClCompile Include="UNKNOWN.cpp" />
   </ItemGroup>
   <ItemGroup>
+    <None Include="..\roms\IO.dump" />
     <None Include="..\roms\Tetris.gb" />
-    <None Include="..\roms\VRAM_TEST_DATA\OAM.dump" />
-    <None Include="..\roms\VRAM_TEST_DATA\OAM_1.dump" />
-    <None Include="..\roms\VRAM_TEST_DATA\OAM_1_2.dump" />
-    <None Include="..\roms\VRAM_TEST_DATA\VRAM.dump" />
-    <None Include="..\roms\VRAM_TEST_DATA\VRAM_1.dump" />
+    <None Include="..\roms\VRAM.dump" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

diff --git a/Gameboy/Gameboy.vcxproj.filters b/Gameboy/Gameboy.vcxproj.filters
@@ -27,6 +27,9 @@
     <ClInclude Include="DisplayUnit.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="CPU.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="olcPixelGameEngine.cpp">
@@ -44,24 +47,33 @@
     <ClCompile Include="DisplayUnit.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="CPU.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="LOAD.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="DECREASE.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="JUMP.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="UNKNOWN.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="COMPARE.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <None Include="..\roms\Tetris.gb">
       <Filter>Resource Files</Filter>
     </None>
-    <None Include="..\roms\VRAM_TEST_DATA\VRAM.dump">
-      <Filter>Resource Files</Filter>
-    </None>
-    <None Include="..\roms\VRAM_TEST_DATA\OAM.dump">
-      <Filter>Resource Files</Filter>
-    </None>
-    <None Include="..\roms\VRAM_TEST_DATA\OAM_1.dump">
-      <Filter>Resource Files</Filter>
-    </None>
-    <None Include="..\roms\VRAM_TEST_DATA\OAM_1_2.dump">
+    <None Include="..\roms\VRAM.dump">
       <Filter>Resource Files</Filter>
     </None>
-    <None Include="..\roms\VRAM_TEST_DATA\VRAM_1.dump">
+    <None Include="..\roms\IO.dump">
       <Filter>Resource Files</Filter>
     </None>
   </ItemGroup>