import qemu

class syborg_timer(qemu.devclass):

  REG_ID            = 0

  REG_LATCH         = 1

  REG_DATA_LOW      = 2

  REG_DATA_HIGH     = 3

  def create(self):

    self.data = 0

    self.offset = qemu.start_time() * 1000000 - qemu.get_clock()

  def read_reg(self, offset):

    offset >>= 2

    if offset == self.REG_ID:

      return 0xc51d0004

    elif offset == self.REG_DATA_LOW:

      return self.data & 0xffffffff

    elif offset == self.REG_DATA_HIGH:

      return (self.data >> 32) & 0xffffffff

    return 0

  def write_reg(self, offset, value):

    offset >>= 2

    if offset == self.REG_LATCH:

      now = qemu.get_clock()

      if value >= 4:

        self.offset = self.data - now

      else:

        self.data = now + self.offset

        while value:

          self.data /= 1000

          value -= 1;

    elif offset == self.REG_DATA_LOW:

      self.data = (self.data & ~0xffffffff) | value

    elif offset == self.REG_DATA_HIGH:

      self.data = (self.data & 0xffffffff) | (value << 32)

  def save(self, f):

    f.put_s64(self.offset)

    f.put_u64(self.data)

  def load(self, f):

    self.offset = f.get_s64()

    self.data = f.get_u64()

  # Device class properties

  regions = [qemu.ioregion(0x1000, readl=read_reg, writel=write_reg)]

  irqs = 0

  name = "syborg,rtc"

  properties = {}

qemu.register_device(syborg_timer)