Class: Rubyboy::Bus

Inherits:
Object
  • Object
show all
Defined in:
lib/rubyboy/bus.rb

Instance Method Summary collapse

Constructor Details

#initialize(ppu, rom, ram, mbc, timer, interrupt, joypad, apu) ⇒ Bus

Returns a new instance of Bus.



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# File 'lib/rubyboy/bus.rb', line 5

def initialize(ppu, rom, ram, mbc, timer, interrupt, joypad, apu)
  @ppu = ppu
  @rom = rom
  @ram = ram
  @mbc = mbc
  @joypad = joypad
  @apu = apu
  @interrupt = interrupt
  @timer = timer
end

Instance Method Details

#read_byte(addr) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 16

def read_byte(addr)
  case addr >> 12
  when 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0xa, 0xb
    return @mbc.read_byte(addr)
  when 0x8, 0x9
    return @ppu.read_byte(addr)
  when 0xc
    return @ram.wram1[addr - 0xc000]
  when 0xd
    return @ram.wram2[addr - 0xd000]
  when 0xf
    case addr >> 8
    when 0xfe
      return @ppu.read_byte(addr) if addr <= 0xfe9f
    when 0xff
      last_byte = addr & 0xFF

      case last_byte
      when 0x00
        return @joypad.read_byte(addr)
      when 0x04, 0x05, 0x06, 0x07
        return @timer.read_byte(addr)
      when 0x0f
        return @interrupt.read_byte(addr)
      when 0x46
        return @ppu.read_byte(addr)
      when 0xff
        return @interrupt.read_byte(addr)
      end

      return @apu.read_byte(addr) if last_byte <= 0x26 && last_byte >= 0x10

      return @apu.read_byte(addr) if last_byte <= 0x3f && last_byte >= 0x30

      return @ppu.read_byte(addr) if last_byte <= 0x4b && last_byte >= 0x40

      return @ram.hram[addr - 0xff80] if last_byte <= 0xfe && last_byte >= 0x80
    end
  end

  0xff
end

#read_word(addr) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 103

def read_word(addr)
  read_byte(addr) + (read_byte(addr + 1) << 8)
end

#write_byte(addr, value) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 59

def write_byte(addr, value)
  case addr >> 12
  when 0x0, 0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0xa, 0xb
    return @mbc.write_byte(addr, value)
  when 0x8, 0x9
    return @ppu.write_byte(addr, value)
  when 0xc
    return @ram.wram1[addr - 0xc000] = value
  when 0xd
    return @ram.wram2[addr - 0xd000] = value
  when 0xf
    case addr >> 8
    when 0xfe
      return @ppu.write_byte(addr, value) if addr <= 0xfe9f
    when 0xff
      last_byte = addr & 0xFF

      case last_byte
      when 0x00
        return @joypad.write_byte(addr, value)
      when 0x04, 0x05, 0x06, 0x07
        return @timer.write_byte(addr, value)
      when 0x0f
        return @interrupt.write_byte(addr, value)
      when 0x46
        0xa0.times { |i| write_byte(0xfe00 + i, read_byte((value << 8) + i)) }
        return
      when 0xff
        return @interrupt.write_byte(addr, value)
      end

      return @apu.write_byte(addr, value) if last_byte <= 0x26 && last_byte >= 0x10

      return @apu.write_byte(addr, value) if last_byte <= 0x3f && last_byte >= 0x30

      return @ppu.write_byte(addr, value) if last_byte <= 0x4b && last_byte >= 0x40

      return @ram.hram[addr - 0xff80] = value if last_byte <= 0xfe && last_byte >= 0x80
    end
  end

  nil
end

#write_word(addr, value) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 107

def write_word(addr, value)
  write_byte(addr, value & 0xff)
  write_byte(addr + 1, value >> 8)
end