Class: GBRb::BaseCartridge

Inherits:
Object
  • Object
show all
Defined in:
lib/gbrb/cartridge/cartridge.rb

Direct Known Subclasses

MBC1

Constant Summary collapse

HEADER_START = 
0x0100
HEADER_END = 
0x014f
TITLE_OFFSET = 
0x34
TITLE_LENGTH = 
0xf
TYPE_OFFSET = 
0x47
DESTINATION_OFFSET = 
0x4a
RAM_BANK_SIZE = 
0x2000

Instance Method Summary collapse

Constructor Details

#initialize(raw_data) ⇒ BaseCartridge

Returns a new instance of BaseCartridge.



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# File 'lib/gbrb/cartridge/cartridge.rb', line 14

def initialize raw_data
  @rom_banks = raw_data.read.each_byte.each_slice(MEMORY_BANK_SIZE).to_a
  @header = rom_bank(0)[HEADER_START..HEADER_END]
  @current_rom_bank = rom_bank 1
  @rom_bank_number = 1
  post_initialize
end

Instance Method Details

#destination ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 129

def destination
  case header_field DESTINATION_OFFSET
  when 0x00
    "Japanese"
  when 0x01
    "Non-Japanese"
  else
    "Unknown"
  end
end

#header_field(offset, length = 1) ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 140

def header_field offset, length=1
  if length == 1
    @header[offset]
  else
    @header.slice offset, length
  end
end

#info ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 51

def info
  "Title:        #{title}\n"        <<
  "Type:         #{type}\n"         <<
  "Destination:  #{destination}\n"  <<
  ""
end

#post_initialize ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 22

def post_initialize; end

#ram_bank(number = 0) ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 28

def ram_bank number=0
  @ram_banks.fetch(number) { Array.new 0x1fff, 0 }
end

#read_byte(addr) ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 32

def read_byte addr
  case addr
  when 0x0000..0x3fff
    @rom_banks[0][addr & (MEMORY_BANK_SIZE - 1)]
  when 0x4000..0x7fff
    rom_bank(@rom_bank_number)[addr & (MEMORY_BANK_SIZE - 1)]
  when 0xa000..0xbfff
    if @current_ram_bank
      @current_ram_bank[addr & (RAM_BANK_SIZE - 1)]
    else
      0
    end
  end
end

#rom_bank(number = 0) ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 24

def rom_bank number=0
  @rom_banks.fetch(number) { Array.new MEMORY_BANK_SIZE, 0 }
end

#title ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 58

def title
  header_field(TITLE_OFFSET, TITLE_LENGTH).select{|el| (0x20..0x7e).cover? el}
                                          .map(&:chr)
                                          .join
end

#type ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 64

def type
  case header_field TYPE_OFFSET
  when 0x00
    "ROM ONLY"
  when 0x01
    "MBC1"
  when 0x02
    "MBC1+RAM"
  when 0x03
    "MBC1+RAM+BATTERY"
  when 0x05
    "MBC2"
  when 0x06
    "MBC2+BATTERY"
  when 0x08
    "ROM+RAM"
  when 0x09
    "ROM+RAM+BATTERY"
  when 0x0b
    "MMM01"
  when 0x0c
    "MMM01+RAM"
  when 0x0d
    "MMM01+RAM+BATTERY"
  when 0x0f
    "MBC3+TIMER+BATTERY"
  when 0x10
    "MBC3+TIMER+RAM+BATTERY"
  when 0x11
    "MBC3"
  when 0x12
    "MBC3+RAM"
  when 0x13
    "MBC3+RAM+BATTERY"
  when 0x15
    "MBC4"
  when 0x16
    "MBC4+RAM"
  when 0x17
    "MBC4+RAM+BATTERY"
  when 0x19
    "MBC5"
  when 0x1a
    "MBC5+RAM"
  when 0x1b
    "MBC5+RAM+BATTERY"
  when 0x1c
    "MBC5+RUMBLE"
  when 0x1d
    "MBC5+RUMBLE+RAM"
  when 0x1e
    "MBC5+RUMBLE+RAM+BATTERY"
  when 0xfc
    "POCKET CAMERA"
  when 0xfd
    "BANDAI TAMA5"
  when 0xfe
    "HuC3"
  when 0xff
    "HuC1+RAM+BATTERY"
  else
    "INVALID"
  end
end

#write_byte(addr, value) ⇒ Object 



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# File 'lib/gbrb/cartridge/cartridge.rb', line 47

def write_byte addr, value
  @current_ram_bank[addr & (ram_bank_size - 1)] = value if (0xa000..0xbfff).cover? addr
end