Emulator: Add LCDC register to PPU

src/emu.cpp

@@ -69,7 +69,8 @@ void Emu::writeMemory(uint32_t address, uint32_t value)
 		if (address == 0xff50) {
 			Loader::the().disableBootrom();
 		}
-		else if (address >= memory.start_address && address <= memory.end_address) {
+
+		if (address >= memory.start_address && address <= memory.end_address) {
 			// Note: ECHO RAM hack
 			if (address >= 0xc000 && address <= 0xddff) {
 				writeMemory(address + (0xe000 - 0xc000), value);

src/ppu.cpp

@@ -5,11 +5,13 @@
  * SPDX-License-Identifier: MIT
  */
 
+#include <cstdint> // uint32_t
+
+#include "emu.h"
 #include "ppu.h"
 #include "ruc/format/print.h"
-#include <iostream>
 
-PPU ::PPU(unsigned int frequency)
+PPU ::PPU(uint32_t frequency)
 	: ProcessingUnit(frequency)
 {
 }
@@ -20,5 +22,10 @@ PPU ::~PPU()
 
 void PPU::update()
 {
-	// print("ppu update\n");
+	LCDC lcd_control = static_cast<LCDC>(Emu::the().readMemory(0xff40));
+	if (!(lcd_control & LCDC::LCDandPPUEnable)) {
+		return;
+	}
+
+	print("PPU update\n");
 }

src/ppu.h

@@ -7,11 +7,26 @@
 
 #pragma once
 
+#include <cstdint> // uint8_t, uint32_t
+
 #include "processing-unit.h"
+#include "ruc/meta/core.h"
+
+enum LCDC : uint8_t {
+	None = 0,
+	BGandWindowEnable = BIT(0),
+	OBJEnable = BIT(1),
+	OBJSize = BIT(2),                 // 0 = 8x8, 1 = 8x16
+	BGTileMapArea = BIT(3),           // 0 = 9800-9bff, 1 = 9c00-9fff
+	BGandWindowTileDataArea = BIT(4), // 0 = 8800-97ff, 1 = 8000-8fff
+	WindowEnable = BIT(5),            //
+	WindowTileMapArea = BIT(6),       // 0 = 9800-9bff, 1 = 9c00-9fff
+	LCDandPPUEnable = BIT(7),
+};
 
 class PPU final : public ProcessingUnit {
 public:
-	PPU(unsigned int frequency);
+	PPU(uint32_t frequency);
 	virtual ~PPU();
 
 	virtual void update() override;