GB: Add basic I/O, interrupts and video

src/gb/gb.c

@@ -5,6 +5,8 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "gb.h"
 
+#include "gb/io.h"
+
 #include "util/crc32.h"
 #include "util/memory.h"
 #include "util/math.h"
@@ -30,17 +32,18 @@ void GBCreate(struct GB* gb) {
 }
 
 static void GBInit(struct LR35902Core* cpu, struct LR35902Component* component) {
-	struct GB* gba = (struct GB*) component;
+	struct GB* gb = (struct GB*) component;
-	gba->cpu = cpu;
+	gb->cpu = cpu;
 
 	GBInterruptHandlerInit(&cpu->irqh);
-	GBMemoryInit(gba);
+	GBMemoryInit(gb);
+	GBVideoInit(&gb->video);
 
-	gba->romVf = 0;
+	gb->romVf = 0;
 
-	gba->pristineRom = 0;
+	gb->pristineRom = 0;
-	gba->pristineRomSize = 0;
+	gb->pristineRomSize = 0;
-	gba->yankedRomSize = 0;
+	gb->yankedRomSize = 0;
 }
 
 bool GBLoadROM(struct GB* gb, struct VFile* vf, struct VFile* sav, const char* fname) {
@@ -120,17 +123,62 @@ void GBReset(struct LR35902Core* cpu) {
 		gb->yankedRomSize = 0;
 	}
 	GBMemoryReset(gb);
+
+	gb->video.p = gb;
+	GBVideoReset(&gb->video);
+}
+
+void GBUpdateIRQs(struct GB* gb) {
+	if (!gb->memory.ime) {
+		return;
+	}
+	int irqs = gb->memory.ie & gb->memory.io[REG_IF];
+	if (!irqs) {
+		return;
+	}
+	if (irqs & (1 << GB_IRQ_VBLANK)) {
+		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_VBLANK);
+		return;
+	}
+	if (irqs & (1 << GB_IRQ_LCDSTAT)) {
+		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_LCDSTAT);
+		return;
+	}
+	if (irqs & (1 << GB_IRQ_TIMER)) {
+		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_TIMER);
+		return;
+	}
+	if (irqs & (1 << GB_IRQ_SIO)) {
+		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_SIO);
+		return;
+	}
+	if (irqs & (1 << GB_IRQ_KEYPAD)) {
+		LR35902RaiseIRQ(gb->cpu, GB_VECTOR_KEYPAD);
+	}
 }
 
 void GBProcessEvents(struct LR35902Core* cpu) {
-	// TODO
+	struct GB* gb = (struct GB*) cpu->master;
+	int32_t cycles = cpu->nextEvent;
+	int32_t nextEvent = INT_MAX;
+	int32_t testEvent;
+
+	testEvent = GBVideoProcessEvents(&gb->video, cycles);
+	if (testEvent < nextEvent) {
+		nextEvent = testEvent;
+	}
+
+	cpu->cycles -= cycles;
+	cpu->nextEvent = nextEvent;
 }
 
 void GBSetInterrupts(struct LR35902Core* cpu, bool enable) {
-	// TODO
+	struct GB* gb = (struct GB*) cpu->master;
+	gb->memory.ime = enable;
+	GBUpdateIRQs(gb);
 }
 
 void GBHitStub(struct LR35902Core* cpu) {
 	// TODO
-	printf("Hit stub at address %04X\n", cpu->pc);
+	//printf("Hit stub at address %04X\n", cpu->pc);
 }

src/gb/gb.h

@@ -11,6 +11,7 @@
 #include "lr35902/lr35902.h"
 
 #include "gb/memory.h"
+#include "gb/video.h"
 
 extern const uint32_t DMG_LR35902_FREQUENCY;
 extern const uint32_t CGB_LR35902_FREQUENCY;
@@ -25,11 +26,20 @@ enum GBIRQ {
 	GB_IRQ_KEYPAD = 0x4,
 };
 
+enum GBIRQVector {
+	GB_VECTOR_VBLANK = 0x40,
+	GB_VECTOR_LCDSTAT = 0x48,
+	GB_VECTOR_TIMER = 0x50,
+	GB_VECTOR_SIO = 0x58,
+	GB_VECTOR_KEYPAD = 0x60,
+};
+
 struct GB {
 	struct LR35902Component d;
 
 	struct LR35902Core* cpu;
 	struct GBMemory memory;
+	struct GBVideo video;
 
 	int* keySource;
 
@@ -47,9 +57,7 @@ void GBDestroy(struct GB* gb);
 
 void GBReset(struct LR35902Core* cpu);
 
-void GBWriteIE(struct GB* gb, uint8_t value);
+void GBUpdateIRQs(struct GB* gb);
-void GBRaiseIRQ(struct GB* gb, enum GBIRQ irq);
-void GBTestIRQ(struct LR35902Core* cpu);
 void GBHalt(struct GB* gb);
 void GBStop(struct GB* gb);
 

src/gb/io.c

@@ -0,0 +1,52 @@
+/* Copyright (c) 2013-2016 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "io.h"
+
+#include "gb/gb.h"
+
+void GBIOInit(struct GB* gb) {
+	memset(gb->memory.io, 0, sizeof(gb->memory.io));
+}
+
+void GBIOWrite(struct GB* gb, unsigned address, uint8_t value) {
+	switch (address) {
+	case REG_IF:
+		gb->memory.io[REG_IF] = value;
+		GBUpdateIRQs(gb);
+		return;
+	case REG_LCDC:
+		// TODO: handle GBC differences
+		GBVideoWriteLCDC(&gb->video, value);
+		break;
+	case REG_IE:
+		gb->memory.ie = value;
+		GBUpdateIRQs(gb);
+		break;
+	default:
+		// TODO: Log
+		if (address >= GB_SIZE_IO) {
+			return;
+		}
+		break;
+	}
+	gb->memory.io[address] = value;
+}
+
+uint8_t GBIORead(struct GB* gb, unsigned address) {
+	switch (address) {
+	case REG_IF:
+		break;
+	case REG_IE:
+		return gb->memory.ie;
+	default:
+		// TODO: Log
+		if (address >= GB_SIZE_IO) {
+			return 0;
+		}
+		break;
+	}
+	return gb->memory.io[address];
+}

src/gb/io.h

@@ -0,0 +1,86 @@
+/* Copyright (c) 2013-2016 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GB_IO_H
+#define GB_IO_H
+
+#include "util/common.h"
+
+enum GBIORegisters {
+	REG_JOYP = 0x00,
+	REG_SB = 0x01,
+	REG_SC = 0x02,
+
+	// Timing
+	REG_DIV = 0x04,
+	REG_TIMA = 0x05,
+	REG_TMA = 0x06,
+	REG_TAC = 0x07,
+
+	// Interrupts
+	REG_IF = 0x0F,
+	REG_IE = 0xFF,
+
+	// Audio
+	REG_NR10 = 0x10,
+	REG_NR11 = 0x11,
+	REG_NR12 = 0x12,
+	REG_NR13 = 0x13,
+	REG_NR14 = 0x14,
+	REG_NR21 = 0x16,
+	REG_NR22 = 0x17,
+	REG_NR23 = 0x18,
+	REG_NR24 = 0x19,
+	REG_NR30 = 0x1A,
+	REG_NR31 = 0x1B,
+	REG_NR32 = 0x1C,
+	REG_NR33 = 0x1D,
+	REG_NR34 = 0x1E,
+	REG_NR41 = 0x20,
+	REG_NR42 = 0x21,
+	REG_NR43 = 0x22,
+	REG_NR44 = 0x23,
+	REG_NR50 = 0x24,
+	REG_NR51 = 0x25,
+	REG_NR52 = 0x26,
+
+	REG_WAVE_0 = 0x30,
+	REG_WAVE_1 = 0x31,
+	REG_WAVE_2 = 0x32,
+	REG_WAVE_3 = 0x33,
+	REG_WAVE_4 = 0x34,
+	REG_WAVE_5 = 0x35,
+	REG_WAVE_6 = 0x36,
+	REG_WAVE_7 = 0x37,
+	REG_WAVE_8 = 0x38,
+	REG_WAVE_9 = 0x39,
+	REG_WAVE_A = 0x3A,
+	REG_WAVE_B = 0x3B,
+	REG_WAVE_C = 0x3C,
+	REG_WAVE_D = 0x3D,
+	REG_WAVE_E = 0x3E,
+	REG_WAVE_F = 0x3F,
+
+	// Video
+	REG_LCDC = 0x40,
+	REG_STAT = 0x41,
+	REG_SCY = 0x42,
+	REG_SCX = 0x43,
+	REG_LY = 0x44,
+	REG_LYC = 0x45,
+	REG_DMA = 0x46,
+	REG_BGP = 0x47,
+	REG_OBP0 = 0x48,
+	REG_OBP1 = 0x49,
+	REG_WY = 0x4A,
+	REG_WX = 0x4B,
+};
+
+struct GB;
+void GBIOInit(struct GB* gb);
+void GBIOWrite(struct GB* gb, unsigned address, uint8_t value);
+uint8_t GBIORead(struct GB* gb, unsigned address);
+
+#endif

src/gb/memory.c

@@ -6,6 +6,7 @@
 #include "memory.h"
 
 #include "gb/gb.h"
+#include "gb/io.h"
 
 #include "util/memory.h"
 
@@ -26,6 +27,10 @@ void GBMemoryInit(struct GB* gb) {
 	gb->memory.rom = 0;
 	gb->memory.romBank = 0;
 	gb->memory.romSize = 0;
+
+	memset(gb->memory.hram, 0, sizeof(gb->memory.hram));
+
+	GBIOInit(gb);
 }
 
 void GBMemoryDeinit(struct GB* gb) {
@@ -80,9 +85,21 @@ uint8_t GBLoad8(struct LR35902Core* cpu, uint16_t address) {
 	case GB_REGION_WORKING_RAM_BANK1:
 		return memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)];
 	default:
+		if (address < GB_BASE_OAM) {
+			return memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)];
+		}
+		if (address < GB_BASE_IO) {
 			// TODO
 			return 0;
 		}
+		if (address < GB_BASE_HRAM) {
+			return GBIORead(gb, address & (GB_SIZE_IO - 1));
+		}
+		if (address < GB_BASE_IE) {
+			return memory->hram[address & GB_SIZE_HRAM];
+		}
+		return GBIORead(gb, REG_IE);
+	}
 }
 
 void GBStore16(struct LR35902Core* cpu, uint16_t address, int16_t value) {
@@ -121,8 +138,17 @@ void GBStore8(struct LR35902Core* cpu, uint16_t address, int8_t value) {
 		memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)] = value;
 		return;
 	default:
+		if (address < GB_BASE_OAM) {
+			memory->wramBank[address & (GB_SIZE_WORKING_RAM_BANK0 - 1)] = value;
+		} else if (address < GB_BASE_IO) {
 			// TODO
-		return;
+		} else if (address < GB_BASE_HRAM) {
+			GBIOWrite(gb, address & (GB_SIZE_IO - 1), value);
+		} else if (address < GB_BASE_IE) {
+			memory->hram[address & GB_SIZE_HRAM] = value;
+		} else {
+			GBIOWrite(gb, REG_IE, value);
+		}
 	}
 }
 

src/gb/memory.h

@@ -54,6 +54,12 @@ struct GBMemory {
 	uint8_t* wram;
 	uint8_t* wramBank;
 
+	uint8_t io[GB_SIZE_IO];
+	bool ime;
+	uint8_t ie;
+
+	uint8_t hram[GB_SIZE_HRAM];
+
 	size_t romSize;
 };
 

src/gb/video.c

@@ -0,0 +1,166 @@
+/* Copyright (c) 2013-2016 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#include "video.h"
+
+#include "gb/gb.h"
+#include "gb/io.h"
+
+#include "util/memory.h"
+
+static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer);
+static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer);
+static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer);
+static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
+static void GBVideoDummyRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address);
+static void GBVideoDummyRendererDrawScanline(struct GBVideoRenderer* renderer, int y);
+static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer);
+static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
+
+static struct GBVideoRenderer dummyRenderer = {
+	.init = GBVideoDummyRendererInit,
+	.reset = GBVideoDummyRendererReset,
+	.deinit = GBVideoDummyRendererDeinit,
+	.writeVideoRegister = GBVideoDummyRendererWriteVideoRegister,
+	.writeVRAM = GBVideoDummyRendererWriteVRAM,
+	.drawScanline = GBVideoDummyRendererDrawScanline,
+	.finishFrame = GBVideoDummyRendererFinishFrame,
+	.getPixels = GBVideoDummyRendererGetPixels
+};
+
+void GBVideoInit(struct GBVideo* video) {
+	video->renderer = &dummyRenderer;
+	video->vram = 0;
+	video->frameskip = 0;
+}
+
+void GBVideoReset(struct GBVideo* video) {
+	video->ly = 0;
+	video->mode = 1;
+
+	video->nextEvent = INT_MAX;
+	video->eventDiff = 0;
+
+	video->nextMode = INT_MAX;
+
+	video->frameCounter = 0;
+	video->frameskipCounter = 0;
+
+	if (video->vram) {
+		mappedMemoryFree(video->vram, GB_SIZE_VRAM);
+	}
+	video->vram = anonymousMemoryMap(GB_SIZE_VRAM);
+	video->renderer->vram = video->vram;
+
+	video->renderer->deinit(video->renderer);
+	video->renderer->init(video->renderer);
+}
+
+void GBVideoDeinit(struct GBVideo* video) {
+	GBVideoAssociateRenderer(video, &dummyRenderer);
+	mappedMemoryFree(video->vram, GB_SIZE_VRAM);
+}
+
+void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer) {
+	// TODO
+}
+
+int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles) {
+	video->eventDiff += cycles;
+	if (video->nextEvent != INT_MAX) {
+		video->nextEvent -= cycles;
+	}
+	if (video->nextEvent <= 0) {
+		if (video->nextEvent != INT_MAX) {
+			video->nextMode -= video->eventDiff;
+		}
+		if (video->nextMode <= 0) {
+			video->mode = (video->mode + 1) & 3;
+			switch (video->mode) {
+			case 0:
+				video->nextMode = GB_VIDEO_MODE_0_LENGTH;
+				break;
+			case 1:
+				video->nextMode = GB_VIDEO_MODE_1_LENGTH;
+				break;
+			case 2:
+				video->nextMode = GB_VIDEO_MODE_2_LENGTH;
+				++video->ly;
+				if (video->ly >= GB_VIDEO_VERTICAL_TOTAL_PIXELS) {
+					video->ly = 0;
+					++video->frameCounter;
+				}
+				video->p->memory.io[REG_LY] = video->ly;
+				break;
+			case 3:
+				video->nextMode = GB_VIDEO_MODE_3_LENGTH;
+				break;
+			}
+		}
+
+		video->nextEvent = video->nextMode;
+		video->eventDiff = 0;
+	}
+	return video->nextEvent;
+}
+
+void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value) {
+	if (!GBRegisterLCDCIsEnable(video->p->memory.io[REG_LCDC]) && GBRegisterLCDCIsEnable(value)) {
+		// TODO: Does enabling the LCD start in vblank?
+		video->mode = 2;
+		video->nextMode = GB_VIDEO_MODE_2_LENGTH;
+		video->nextEvent = video->nextMode;
+		video->eventDiff = 0;
+		if (video->nextEvent < video->p->cpu->nextEvent) {
+			video->p->cpu->nextEvent = video->nextEvent;
+		}
+		return;
+	}
+}
+
+static void GBVideoDummyRendererInit(struct GBVideoRenderer* renderer) {
+	UNUSED(renderer);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererReset(struct GBVideoRenderer* renderer) {
+	UNUSED(renderer);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererDeinit(struct GBVideoRenderer* renderer) {
+	UNUSED(renderer);
+	// Nothing to do
+}
+
+static uint8_t GBVideoDummyRendererWriteVideoRegister(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value) {
+	UNUSED(renderer);
+	UNUSED(address);
+	return value;
+}
+
+static void GBVideoDummyRendererWriteVRAM(struct GBVideoRenderer* renderer, uint16_t address) {
+	UNUSED(renderer);
+	UNUSED(address);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererDrawScanline(struct GBVideoRenderer* renderer, int y) {
+	UNUSED(renderer);
+	UNUSED(y);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererFinishFrame(struct GBVideoRenderer* renderer) {
+	UNUSED(renderer);
+	// Nothing to do
+}
+
+static void GBVideoDummyRendererGetPixels(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels) {
+	UNUSED(renderer);
+	UNUSED(stride);
+	UNUSED(pixels);
+	// Nothing to do
+}

src/gb/video.h

@@ -0,0 +1,78 @@
+/* Copyright (c) 2013-2016 Jeffrey Pfau
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+#ifndef GB_VIDEO_H
+#define GB_VIDEO_H
+
+#include "util/common.h"
+
+#include "gb/memory.h"
+
+enum {
+	GB_VIDEO_HORIZONTAL_PIXELS = 160,
+	GB_VIDEO_VERTICAL_PIXELS = 144,
+	GB_VIDEO_VBLANK_PIXELS = 10,
+	GB_VIDEO_VERTICAL_TOTAL_PIXELS = GB_VIDEO_VERTICAL_PIXELS + GB_VIDEO_VBLANK_PIXELS,
+
+	GB_VIDEO_MODE_0_LENGTH = 203, // Estimates, figure out with more precision
+	GB_VIDEO_MODE_2_LENGTH = 81,
+	GB_VIDEO_MODE_3_LENGTH = 172,
+
+	GB_VIDEO_HORIZONTAL_LENGTH = GB_VIDEO_MODE_0_LENGTH + GB_VIDEO_MODE_2_LENGTH + GB_VIDEO_MODE_3_LENGTH,
+
+	GB_VIDEO_MODE_1_LENGTH = GB_VIDEO_HORIZONTAL_LENGTH * GB_VIDEO_VBLANK_PIXELS,
+	GB_VIDEO_TOTAL_LENGTH = GB_VIDEO_HORIZONTAL_LENGTH * GB_VIDEO_VERTICAL_TOTAL_PIXELS,
+};
+
+struct GBVideoRenderer {
+	void (*init)(struct GBVideoRenderer* renderer);
+	void (*reset)(struct GBVideoRenderer* renderer);
+	void (*deinit)(struct GBVideoRenderer* renderer);
+
+	uint8_t (*writeVideoRegister)(struct GBVideoRenderer* renderer, uint16_t address, uint8_t value);
+	void (*writeVRAM)(struct GBVideoRenderer* renderer, uint16_t address);
+	void (*drawScanline)(struct GBVideoRenderer* renderer, int y);
+	void (*finishFrame)(struct GBVideoRenderer* renderer);
+
+	void (*getPixels)(struct GBVideoRenderer* renderer, unsigned* stride, const void** pixels);
+	void (*putPixels)(struct GBVideoRenderer* renderer, unsigned stride, void* pixels);
+
+	uint8_t* vram;
+};
+
+DECL_BITFIELD(GBRegisterLCDC, uint8_t);
+DECL_BIT(GBRegisterLCDC, Enable, 7);
+
+DECL_BITFIELD(GBRegisterSTAT, uint8_t);
+
+struct GBVideo {
+	struct GB* p;
+	struct GBVideoRenderer* renderer;
+
+	int ly;
+	int mode;
+
+	int32_t nextEvent;
+	int32_t eventDiff;
+
+	int32_t nextMode;
+
+	uint8_t* vram;
+
+	int32_t frameCounter;
+	int frameskip;
+	int frameskipCounter;
+};
+
+void GBVideoInit(struct GBVideo* video);
+void GBVideoReset(struct GBVideo* video);
+void GBVideoDeinit(struct GBVideo* video);
+void GBVideoAssociateRenderer(struct GBVideo* video, struct GBVideoRenderer* renderer);
+int32_t GBVideoProcessEvents(struct GBVideo* video, int32_t cycles);
+
+void GBVideoWriteLCDC(struct GBVideo* video, GBRegisterLCDC value);
+void GBVideoWriteSTAT(struct GBVideo* video, GBRegisterSTAT value);
+
+#endif

src/lr35902/lr35902.c

@@ -69,8 +69,9 @@ void LR35902Reset(struct LR35902Core* cpu) {
 	cpu->irqh.reset(cpu);
 }
 
-void LR35902RaiseIRQ(struct LR35902Core* cpu) {
+void LR35902RaiseIRQ(struct LR35902Core* cpu, uint8_t vector) {
-	// TODO
+	cpu->irqPending = true;
+	cpu->irqVector = vector;
 }
 
 void LR35902Tick(struct LR35902Core* cpu) {
@@ -80,6 +81,12 @@ void LR35902Tick(struct LR35902Core* cpu) {
 	cpu->executionState &= 3;
 	switch (state) {
 	case LR35902_CORE_FETCH:
+		if (cpu->irqPending) {
+			cpu->pc = cpu->irqVector;
+			cpu->irqPending = false;
+			cpu->irqh.setInterrupts(cpu, false);
+			// TODO: stall
+		}
 		cpu->bus = cpu->memory.load8(cpu, cpu->pc);
 		break;
 	case LR35902_CORE_DECODE:

src/lr35902/lr35902.h

@@ -120,6 +120,9 @@ struct LR35902Core {
 	bool condition;
 	LR35902Instruction instruction;
 
+	bool irqPending;
+	uint16_t irqVector;
+
 	struct LR35902Memory memory;
 	struct LR35902InterruptHandler irqh;
 
@@ -142,7 +145,7 @@ void LR35902HotplugAttach(struct LR35902Core* cpu, size_t slot);
 void LR35902HotplugDetach(struct LR35902Core* cpu, size_t slot);
 
 void LR35902Reset(struct LR35902Core* cpu);
-void LR35902RaiseIRQ(struct LR35902Core*);
+void LR35902RaiseIRQ(struct LR35902Core* cpu, uint8_t vector);
 
 void LR35902Tick(struct LR35902Core* cpu);