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

  @read_methods = Array.new(0x10000)
  @write_methods = Array.new(0x10000)

  set_methods
end

Instance Method Details

#read_byte(addr) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 76

def read_byte(addr)
  @read_methods[addr].call
end

#read_word(addr) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 84

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

#set_methods ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 21

def set_methods
  0x10000.times do |addr|
    case addr
    when 0x0000..0x7fff
      @read_methods[addr] = -> { @mbc.read_byte(addr) }
      @write_methods[addr] = ->(value) { @mbc.write_byte(addr, value) }
    when 0x8000..0x9fff
      @read_methods[addr] = -> { @ppu.read_byte(addr) }
      @write_methods[addr] = ->(value) { @ppu.write_byte(addr, value) }
    when 0xa000..0xbfff
      @read_methods[addr] = -> { @mbc.read_byte(addr) }
      @write_methods[addr] = ->(value) { @mbc.write_byte(addr, value) }
    when 0xc000..0xcfff
      @read_methods[addr] = -> { @ram.wram1[addr - 0xc000] }
      @write_methods[addr] = ->(value) { @ram.wram1[addr - 0xc000] = value }
    when 0xd000..0xdfff
      @read_methods[addr] = -> { @ram.wram2[addr - 0xd000] }
      @write_methods[addr] = ->(value) { @ram.wram2[addr - 0xd000] = value }
    when 0xfe00..0xfe9f
      @read_methods[addr] = -> { @ppu.read_byte(addr) }
      @write_methods[addr] = ->(value) { @ppu.write_byte(addr, value) }
    when 0xff00
      @read_methods[addr] = -> { @joypad.read_byte(addr) }
      @write_methods[addr] = ->(value) { @joypad.write_byte(addr, value) }
    when 0xff04..0xff07
      @read_methods[addr] = -> { @timer.read_byte(addr) }
      @write_methods[addr] = ->(value) { @timer.write_byte(addr, value) }
    when 0xff0f
      @read_methods[addr] = -> { @interrupt.read_byte(addr) }
      @write_methods[addr] = ->(value) { @interrupt.write_byte(addr, value) }
    when 0xff10..0xff26
      @read_methods[addr] = -> { @apu.read_byte(addr) }
      @write_methods[addr] = ->(value) { @apu.write_byte(addr, value) }
    when 0xff30..0xff3f
      @read_methods[addr] = -> { @apu.read_byte(addr) }
      @write_methods[addr] = ->(value) { @apu.write_byte(addr, value) }
    when 0xff46
      @read_methods[addr] = -> { @ppu.read_byte(addr) }
      @write_methods[addr] = ->(value) { 0xa0.times { |i| write_byte(0xfe00 + i, read_byte((value << 8) + i)) } }
    when 0xff40..0xff4b
      @read_methods[addr] = -> { @ppu.read_byte(addr) }
      @write_methods[addr] = ->(value) { @ppu.write_byte(addr, value) }
    when 0xff80..0xfffe
      @read_methods[addr] = -> { @ram.hram[addr - 0xff80] }
      @write_methods[addr] = ->(value) { @ram.hram[addr - 0xff80] = value }
    when 0xffff
      @read_methods[addr] = -> { @interrupt.read_byte(addr) }
      @write_methods[addr] = ->(value) { @interrupt.write_byte(addr, value) }
    else
      @read_methods[addr] = -> { 0xff }
      @write_methods[addr] = ->(_value) {}
    end
  end
end

#write_byte(addr, value) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 80

def write_byte(addr, value)
  @write_methods[addr].call(value)
end

#write_word(addr, value) ⇒ Object 



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# File 'lib/rubyboy/bus.rb', line 88

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