added mapper mbc1

NES Emulator/mappers/mapper001.c

@@ -0,0 +1,175 @@
+#include "mapper001.h"
+
+struct Mapper001* createMapper001(Byte prg_rom_size, Byte chr_rom_size, FILE* fp)
+{
+	struct Mapper001* mapper = (struct Mapper001*)malloc(sizeof(struct Mapper001));
+	if (mapper == NULL)
+	{
+		fprintf(stderr, "Failed to create Mapper 000. Aborting\n");
+		exit(-1);
+	}
+
+	mapper->prg_rom_size = prg_rom_size;
+	mapper->prg_rom = (Byte*)calloc(prg_rom_size, 0x4000);
+	if (mapper->prg_rom == NULL)
+	{
+		fprintf(stderr, "Failed to allocate cartridge PRG ROM. Aborting\n");
+		exit(-1);
+	}
+
+	mapper->chr_rom_size = chr_rom_size;
+	mapper->chr_rom = (Byte*)calloc(chr_rom_size, 0x2000);
+	if (mapper->chr_rom == NULL)
+	{
+		fprintf(stderr, "Failed to allocate cartridge CHR ROM. Aborting\n");
+		exit(-1);
+	}
+
+	fread(mapper->prg_rom, 0x4000, prg_rom_size, fp);
+	fread(mapper->chr_rom, 0x2000, chr_rom_size, fp);
+
+	mapper->lowerChrBank = mapper->chr_rom;
+	mapper->upperChrBank = mapper->chr_rom + 0x1000;
+	mapper->lowerPrgBank = mapper->prg_rom;
+	mapper->upperPrgBank = mapper->prg_rom + 0x4000;
+
+	return mapper;
+}
+
+void destroyMapper001(struct Mapper001* mapper)
+{
+	free(mapper->chr_rom);
+	free(mapper->prg_rom);
+
+	free(mapper);
+}
+
+Byte Mapper001_ReadCPU(void* mapper, Word address)
+{
+	struct Mapper001* sMapper = (struct Mapper000*)mapper;
+	Byte val = 0x00;
+
+	if (address >= 0x6000 && address < 0x8000)
+	{
+		fprintf(stderr, "This Mapper 000 implementation doesnt support FamilyBasic PRG RAM\n");
+		exit(-1);
+	}
+	else if (address >= 0x8000 && address <= 0xBFFF)
+	{
+		val = sMapper->lowerPrgBank[address & 0x3FFF];
+	}
+	else if (address >= 0xC000 && address <= 0xFFFF)
+	{
+		val = sMapper->upperPrgBank[address & 0x3FFF];
+	}
+	else
+	{
+		fprintf(stderr, "Cartridge read access violation by the CPU at $%04X\n", address);
+		exit(-1);
+	}
+
+	return val;
+}
+
+Byte Mapper001_ReadPPU(void* mapper, Word address)
+{
+	struct Mapper001* sMapper = (struct Mapper000*)mapper;
+	Byte val = 0x00;
+
+	if (address >= 0x2000)
+	{
+		fprintf(stderr, "Cartridge read access violation by the PPU at $%04X\n", address);
+		exit(-1);
+	}
+	else if (address < 0x1000 + 0x1000 * (1 - sMapper->control.chr_bank_mode))
+	{
+		val = sMapper->lowerChrBank[address];
+	}
+	else
+	{
+		val = sMapper->upperChrBank[address & 0x0FFF];
+	}
+
+	return val;
+}
+
+void Mapper001_WriteCPU(void* mapper, Word address, Byte value)
+{
+	struct Mapper001* sMapper = (struct Mapper000*)mapper;
+	if ((value & 0x80) == 0x80)
+	{
+		sMapper->shiftRegister = 0x10;
+		sMapper->control.raw |= 0x0C;
+		return;
+	}
+
+	if ((sMapper->shiftRegister & 0x1) != 0x1)
+	{
+		sMapper->shiftRegister >>= 1;
+		sMapper->shiftRegister |= ((value & 0x1) << 4);
+		return;
+	}
+
+	Byte valueToBeWritten = (sMapper->shiftRegister >> 1) | ((value & 0x1) << 4);
+	if (address >= 0x8000 && address <= 0x9FFF)
+	{
+		sMapper->control.raw = valueToBeWritten;
+	}
+	else if (address >= 0xA000 && address <= 0xBFFF)
+	{
+		if (sMapper->control.chr_bank_mode == 0x00)	// 8KB mode
+			valueToBeWritten &= ~(0x1);	// clear last bit
+
+		sMapper->lowerChrBank = sMapper->chr_rom + (size_t)valueToBeWritten * 0x1000;
+	}
+	else if (address >= 0xC000 && address <= 0xDFFF)
+	{
+		if (sMapper->control.chr_bank_mode == 0x00)	// 8KB mode
+		{
+			return;	// ignore
+		}
+
+		sMapper->upperChrBank = sMapper->chr_rom + (size_t)valueToBeWritten * 0x1000;
+	}
+	else
+	{
+		switch (sMapper->control.prg_bank_mode)
+		{
+		case 0: // 32KB mode
+		case 1: 
+			valueToBeWritten &= ~(0x1);
+			sMapper->lowerPrgBank = sMapper->prg_rom + ((size_t)valueToBeWritten & 0xE) * 0x8000;
+			sMapper->upperPrgBank = sMapper->lowerPrgBank + 0x4000;
+			break;
+
+		case 2: // fix first bank, switch second
+			sMapper->lowerPrgBank = sMapper->prg_rom;
+			sMapper->upperPrgBank = sMapper->prg_rom + ((size_t)valueToBeWritten & 0xE) * 0x4000;
+			break;
+
+		case 3: // fix last bank, switch first
+			sMapper->lowerPrgBank = sMapper->prg_rom + ((size_t)valueToBeWritten & 0xE) * 0x4000;
+			sMapper->upperPrgBank = sMapper->prg_rom + ((size_t)sMapper->prg_rom_size - 1) * 0x4000;
+			break;
+
+		}
+	}
+}
+
+
+void Mapper001_WritePPU(void* mapper, Word address, Byte value)
+{
+	// nothing
+}
+
+void Mapper001_GetPatternTableTexture(void* mapper, SDL_Texture* texture, int index)
+{
+	struct Mapper001* sMapper = (struct Mapper001*)mapper;
+	Byte* selectedBank = ((index == 0) ? sMapper->lowerChrBank : sMapper->upperChrBank);
+
+	int pitch;
+	void* pixels;
+	SDL_LockTexture(texture, NULL, &pixels, &pitch);
+	SDL_memcpy(pixels, selectedBank, 0x1000);
+	SDL_UnlockTexture(texture);
+}

NES Emulator/mappers/mapper001.h

@@ -0,0 +1,50 @@
+#ifndef _MAPPER_001_
+#define _MAPPER_001_
+
+#include <stdio.h>
+#include "../types.h"
+#include "SDL.h"
+
+struct Mapper001
+{
+	Byte prg_rom_size;
+	Byte chr_rom_size;
+
+	Byte* prg_rom;
+	Byte* chr_rom;
+
+	///////////////////////////
+	///      REGISTERS      ///
+	///////////////////////////
+	Byte shiftRegister;
+	
+	union
+	{
+		struct
+		{
+			Byte mirroring : 2;
+			Byte prg_bank_mode : 2;
+			Byte chr_bank_mode : 1;
+			Byte padding : 3;
+		};
+
+		Byte raw;
+	} control;
+
+	Byte* lowerChrBank;
+	Byte* upperChrBank;
+	Byte* lowerPrgBank;
+	Byte* upperPrgBank;
+};
+
+struct Mapper001* createMapper001(Byte prg_rom_size, Byte chr_rom_size, FILE* fp);
+void destroyMapper001(struct Mapper001* mapper);
+
+Byte Mapper001_ReadCPU(void* mapper, Word address);
+Byte Mapper001_ReadPPU(void* mapper, Word address);
+void Mapper001_WriteCPU(void* mapper, Word address, Byte value);
+void Mapper001_WritePPU(void* mapper, Word address, Byte value);
+
+void Mapper001_GetPatternTableTexture(void* mapper, SDL_Texture* texture, int index);
+
+#endif // _MAPPER_001_