Class: Badline::AddressBus

Inherits:
Object
  • Object
show all
Includes:
Addressable
Defined in:
lib/badline/address_bus.rb

Overview

Overlays:

0x8000-0x9FFF - Cartridge ROM (low) - 8kb 0xA000-0xBFFF - BASIC ROM / Cartridge ROM (high) - 8kb 0xD000-0xDFFF - Character ROM / I/O - 4kb 0xE000-0xFFFF - KERNAL ROM / Cartridge ROM (high) - 8kb

Defined Under Namespace

Modules: OpenSpace

Constant Summary collapse

PORT_PULLUPS = 
0b0001_0111
PORT_FLOATING = 
0b1100_1000

Instance Attribute Summary collapse

Attributes included from Addressable

#end, #length, #start

Instance Method Summary collapse

Methods included from Addressable

#[], #[]=, #addressable_at, #in_range?, #peek16, #poke16, #range

Methods included from IntegerHelper

#bcd, #bcd_to_i, #format16, #format8, #high_byte, #low_byte, #signed_int8, #uint16

Constructor Details

#initialize ⇒ AddressBus

Returns a new instance of AddressBus.



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# File 'lib/badline/address_bus.rb', line 47

def initialize
  @ram = Memory.new([0xff, 0x07], length: 2**16, start: 0)
  @cartridge = nil

  @basic_rom     = ROM.load("basic.rom",     0xa000)
  @character_rom = ROM.load("character.rom", 0xd000)
  @kernal_rom    = ROM.load("kernal.rom",    0xe000)

  @keyboard = Keyboard.new
  @joystick2 = Joystick.new
  @vic  = VIC.new(self)
  @cia1 = CIA.new(
    start: 0xdc00,
    peripheral: ControlPorts.new(keyboard: @keyboard, joystick2: @joystick2)
  )
  @cia2 = CIA.new(start: 0xdd00)
  @sid  = SID.new

  @color_ram = ColorMemory.new(start: 0xd800, length: 2**10)

  @port_ddr = 0x2f
  @port_out = 0x37
  @port_floating = 0x00
  @io_port = Status.new(%i[basic kernal io tape_out tape_switch tape_motor], value: port_value)

  @read_pages = Array.new(256)
  @write_pages = Array.new(256)
  update_overlays!
end

Instance Attribute Details

#basic_rom ⇒ Object (readonly)

Returns the value of attribute basic_rom.



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# File 'lib/badline/address_bus.rb', line 43

def basic_rom
  @basic_rom
end

#cartridge ⇒ Object (readonly)

Returns the value of attribute cartridge.



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# File 'lib/badline/address_bus.rb', line 43

def cartridge
  @cartridge
end

#character_rom ⇒ Object (readonly)

Returns the value of attribute character_rom.



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# File 'lib/badline/address_bus.rb', line 43

def character_rom
  @character_rom
end

#cia1 ⇒ Object (readonly)

Returns the value of attribute cia1.



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# File 'lib/badline/address_bus.rb', line 43

def cia1
  @cia1
end

#cia2 ⇒ Object (readonly)

Returns the value of attribute cia2.



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# File 'lib/badline/address_bus.rb', line 43

def cia2
  @cia2
end

#color_ram ⇒ Object (readonly)

Returns the value of attribute color_ram.



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# File 'lib/badline/address_bus.rb', line 43

def color_ram
  @color_ram
end

#io_port ⇒ Object (readonly)

Returns the value of attribute io_port.



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# File 'lib/badline/address_bus.rb', line 43

def io_port
  @io_port
end

#joystick2 ⇒ Object (readonly)

Returns the value of attribute joystick2.



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# File 'lib/badline/address_bus.rb', line 43

def joystick2
  @joystick2
end

#kernal_rom ⇒ Object (readonly)

Returns the value of attribute kernal_rom.



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# File 'lib/badline/address_bus.rb', line 43

def kernal_rom
  @kernal_rom
end

#keyboard ⇒ Object (readonly)

Returns the value of attribute keyboard.



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# File 'lib/badline/address_bus.rb', line 43

def keyboard
  @keyboard
end

#ram ⇒ Object (readonly)

Returns the value of attribute ram.



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# File 'lib/badline/address_bus.rb', line 43

def ram
  @ram
end

#sid ⇒ Object (readonly)

Returns the value of attribute sid.



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# File 'lib/badline/address_bus.rb', line 43

def sid
  @sid
end

#ultimax ⇒ Object (readonly)

Returns the value of attribute ultimax.



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# File 'lib/badline/address_bus.rb', line 43

def ultimax
  @ultimax
end

#vic ⇒ Object (readonly)

Returns the value of attribute vic.



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# File 'lib/badline/address_bus.rb', line 43

def vic
  @vic
end

Instance Method Details

#attach_cartridge(cartridge) ⇒ Object 



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# File 'lib/badline/address_bus.rb', line 77

def attach_cartridge(cartridge)
  @cartridge = cartridge
  cartridge.on_change { update_overlays! }
  update_overlays!
end

#disable_overlays! ⇒ Object 



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# File 'lib/badline/address_bus.rb', line 83

def disable_overlays!
  poke(1, 0)
end

#inspect ⇒ Object 



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# File 'lib/badline/address_bus.rb', line 103

def inspect
  "#<#{self.class.name} port=#{format('0x%02x', @io_port.value)} " \
    "cartridge=#{@cartridge ? @cartridge.class.name : 'none'} " \
    "ultimax=#{@ultimax}>"
end

#peek(addr) ⇒ Object 



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# File 'lib/badline/address_bus.rb', line 87

def peek(addr)
  return @port_ddr if addr.zero?
  return @io_port.value if addr == 0x01

  @read_pages[addr >> 8].peek(addr)
end

#poke(addr, value) ⇒ Object 



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# File 'lib/badline/address_bus.rb', line 94

def poke(addr, value)
  if addr < 0x02
    addr.zero? ? @port_ddr = value : @port_out = value
    update_port!
  else
    @write_pages[addr >> 8].poke(addr, value)
  end
end