js/savedata.js

function SRAMSavedata(size) {
	MemoryView.call(this, new ArrayBuffer(size), 0);

	this.writePending = false;
};

SRAMSavedata.prototype = Object.create(MemoryView.prototype);

SRAMSavedata.prototype.store8 = function(offset, value) {
	this.view.setInt8(offset, value);
	this.writePending = true;
};

SRAMSavedata.prototype.store16 = function(offset, value) {
	this.view.setInt16(offset, value, true);
	this.writePending = true;
};

SRAMSavedata.prototype.store32 = function(offset, value) {
	this.view.setInt32(offset, value, true);
	this.writePending = true;
};

function FlashSavedata(size) {
	MemoryView.call(this, new ArrayBuffer(size), 0);

	this.COMMAND_WIPE = 0x10;
	this.COMMAND_ERASE_SECTOR = 0x30;
	this.COMMAND_ERASE = 0x80;
	this.COMMAND_ID = 0x90;
	this.COMMAND_WRITE = 0xA0;
	this.COMMAND_SWITCH_BANK = 0xB0;
	this.COMMAND_TERMINATE_ID = 0xF0;

	this.ID_PANASONIC = 0x1B32;
	this.ID_SANYO = 0x1362;

	this.bank0 = new DataView(this.buffer, 0, 0x00010000);
	if (size > 0x00010000) {
		this.id = this.ID_SANYO;
		this.bank1 = new DataView(this.buffer, 0x00010000);
	} else {
		this.id = this.ID_PANASONIC;
		this.bank1 = null;
	}
	this.bank = this.bank0;

	this.idMode = false;
	this.writePending = false;

	this.first = 0;
	this.second = 0;
	this.command = 0;
	this.pendingCommand = 0;
};

FlashSavedata.prototype = Object.create(MemoryView.prototype);

FlashSavedata.prototype.load8 = function(offset) {
	if (this.idMode && offset < 2) {
		return (this.id >> (offset << 3)) & 0xFF;
	} else if (offset < 0x10000) {
		return this.bank.getInt8(offset);
	} else {
		return 0;
	}
};

FlashSavedata.prototype.load16 = function(offset) {
	return (this.load8(offset) & 0xFF) | (this.load8(offset + 1) << 8);
};

FlashSavedata.prototype.load32 = function(offset) {
	return (this.load8(offset) & 0xFF) | (this.load8(offset + 1) << 8) | (this.load8(offset + 2) << 16) | (this.load8(offset + 3) << 24);
};

FlashSavedata.prototype.loadU8 = function(offset) {
	return this.load8(offset) & 0xFF;
};

FlashSavedata.prototype.loadU16 = function(offset) {
	return (this.loadU8(offset) & 0xFF) | (this.loadU8(offset + 1) << 8);
};

FlashSavedata.prototype.store8 = function(offset, value) {
	switch (this.command) {
	case 0:
		if (offset == 0x5555) {
			if (this.second == 0x55) {
				switch (value) {
				case this.COMMAND_ERASE:
					this.pendingCommand = value;
					break;
				case this.COMMAND_ID:
					this.idMode = true;
					break;
				case this.COMMAND_TERMINATE_ID:
					this.idMode = false;
					break;
				default:
					this.command = value;
					break;
				}
				this.second = 0;
				this.first = 0;
			} else {
				this.command = 0;
				this.first = value;
				this.idMode = false;
			}
		} else if (offset == 0x2AAA && this.first == 0xAA) {
			this.first = 0;
			if (this.pendingCommand) {
				this.command = this.pendingCommand;
			} else {
				this.second = value;
			}
		}
		break;
	case this.COMMAND_ERASE:
		switch (value) {
		case this.COMMAND_WIPE:
			if (offset == 0x5555) {
				for (var i = 0; i < this.view.byteLength; i += 4) {
					this.view.setInt32(i, -1);
				}
			}
			break;
		case this.COMMAND_ERASE_SECTOR:
			if ((offset & 0x0FFF) == 0) {
				for (var i = offset; i < offset + 0x1000; i += 4) {
					this.bank.setInt32(i, -1);
				}
			}
			break;
		}
		this.pendingCommand = 0;
		this.command = 0;
		break;
	case this.COMMAND_WRITE:
		this.bank.setInt8(offset, value);
		this.command = 0;

		this.writePending = true;
		break;
	case this.COMMAND_SWITCH_BANK:
		if (this.bank1 && offset == 0) {
			if (value == 1) {
				this.bank = this.bank1;
			} else {
				this.bank = this.bank0;
			}
		}
		this.command = 0;
		break;
	}
};

FlashSavedata.prototype.store16 = function(offset, value) {
	throw new Error("Unaligned save to flash!");
};

FlashSavedata.prototype.store32 = function(offset, value) {
	throw new Error("Unaligned save to flash!");
};

FlashSavedata.prototype.replaceData = function(memory) {
	var bank = this.view === this.bank1;
	MemoryView.prototype.replaceData.call(this, memory, 0);

	this.bank0 = new DataView(this.buffer, 0, 0x00010000);
	if (memory.byteLength > 0x00010000) {
		this.bank1 = new DataView(this.buffer, 0x00010000);
	} else {
		this.bank1 = null;
	}
	this.bank = bank ? this.bank1 : this.bank0;
};

function EEPROMSavedata(size, mmu) {
	MemoryView.call(this, new ArrayBuffer(size), 0);

	this.writeAddress = 0;
	this.readBitsRemaining = 0;
	this.readAddress = 0;

	this.command = 0;
	this.commandBitsRemaining = 0;

	this.realSize = 0;
	this.addressBits = 0;
	this.writePending = false;

	this.dma = mmu.core.irq.dma[3];

	this.COMMAND_NULL = 0;
	this.COMMAND_PENDING = 1;
	this.COMMAND_WRITE = 2;
	this.COMMAND_READ_PENDING = 3;
	this.COMMAND_READ = 4;
};

EEPROMSavedata.prototype = Object.create(MemoryView.prototype);

EEPROMSavedata.prototype.load8 = function(offset) {
	throw new Error("Unsupported 8-bit access!");
};

EEPROMSavedata.prototype.load16 = function(offset) {
	return this.loadU16(offset);
};

EEPROMSavedata.prototype.loadU8 = function(offset) {
	throw new Error("Unsupported 8-bit access!");
};

EEPROMSavedata.prototype.loadU16 = function(offset) {
	if (this.command != this.COMMAND_READ || !this.dma.enable) {
		return 1;
	}
	--this.readBitsRemaining;
	if (this.readBitsRemaining < 64) {
		var step = 63 - this.readBitsRemaining;
		var data = this.view.getUint8((this.readAddress + step) >> 3, false) >> (0x7 - (step & 0x7));
		if (!this.readBitsRemaining) {
			this.command = this.COMMAND_NULL;
		}
		return data & 0x1;
	}
	return 0;
};

EEPROMSavedata.prototype.load32 = function(offset) {
	throw new Error("Unsupported 32-bit access!");
};

EEPROMSavedata.prototype.store8 = function(offset, value) {
	throw new Error("Unsupported 8-bit access!");
};

EEPROMSavedata.prototype.store16 = function(offset, value) {
	switch (this.command) {
	// Read header
	case this.COMMAND_NULL:
	default:
		this.command = value & 0x1;
		break;
	case this.COMMAND_PENDING:
		this.command <<= 1;
		this.command |= value & 0x1;
		if (this.command == this.COMMAND_WRITE) {
			if (!this.realSize) {
				var bits = this.dma.count - 67;
				this.realSize = 8 << bits;
				this.addressBits = bits;
			}
			this.commandBitsRemaining = this.addressBits + 64 + 1;
			this.writeAddress = 0;
		} else {
			if (!this.realSize) {
				var bits = this.dma.count - 3;
				this.realSize = 8 << bits;
				this.addressBits = bits;
			}
			this.commandBitsRemaining = this.addressBits + 1;
			this.readAddress = 0;
		}
		break;
	// Do commands
	case this.COMMAND_WRITE:
		// Write
		if (--this.commandBitsRemaining > 64) {
			this.writeAddress <<= 1;
			this.writeAddress |= (value & 0x1) << 6;
		} else if (this.commandBitsRemaining <= 0) {
			this.command = this.COMMAND_NULL;
			this.writePending = true;
		} else {
			var current = this.view.getUint8(this.writeAddress >> 3);
			current &= ~(1 << (0x7 - (this.writeAddress & 0x7)));
			current |= (value & 0x1) << (0x7 - (this.writeAddress & 0x7));
			this.view.setUint8(this.writeAddress >> 3, current);
			++this.writeAddress;
		}
		break;
	case this.COMMAND_READ_PENDING:
		// Read
		if (--this.commandBitsRemaining > 0) {
			this.readAddress <<= 1;
			if (value & 0x1) {
				this.readAddress |= 0x40;
			}
		} else {
			this.readBitsRemaining = 68;
			this.command = this.COMMAND_READ;
		}
		break;
	}
};

EEPROMSavedata.prototype.store32 = function(offset, value) {
	throw new Error("Unsupported 32-bit access!");
};

EEPROMSavedata.prototype.replaceData = function(memory) {
	MemoryView.prototype.replaceData.call(this, memory, 0);
};