# -*- coding: utf-8 -*-
#
# AWL simulator - Dummy hardware interface
#
# Copyright 2013 Michael Buesch <m@bues.ch>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#

from awlsim.hardware import *
from awlsim.operators import AwlOperator
from awlsim.datatypes import AwlOffset


class HardwareInterface(AbstractHardwareInterface):
	name = "dummy"

	paramDescs = [
		HwParamDesc_bool("dummyParam",
				 description = "Unused dummy parameter"),
	]

	def __init__(self, sim, parameters={}):
		AbstractHardwareInterface.__init__(self,
						   sim = sim,
						   parameters = parameters)

	def doStartup(self):
		pass # Do nothing

	def doShutdown(self):
		pass # Do nothing

	def readInputs(self):
		# Get the first input dword and write it back.
		dword = self.sim.cpu.fetch(AwlOperator(AwlOperator.MEM_E,
						       32,
						       AwlOffset(self.inputAddressBase)))
		dwordBytes = bytearray( ( ((dword >> 24) & 0xFF),
					  ((dword >> 16) & 0xFF),
					  ((dword >> 8) & 0xFF),
					  (dword & 0xFF) ) )
		self.sim.cpu.storeInputRange(self.inputAddressBase,
					     dwordBytes)

	def writeOutputs(self):
		# Fetch a data range, but don't do anything with it.
		outData = self.sim.cpu.fetchOutputRange(self.outputAddressBase,
							512)
		assert(outData)

	def directReadInput(self, accessWidth, accessOffset):
		if accessOffset < self.inputAddressBase:
			return None
		# Just read the current value from the CPU and return it.
		return self.sim.cpu.fetch(AwlOperator(AwlOperator.MEM_E,
						      accessWidth,
						      AwlOffset(accessOffset)))

	def directWriteOutput(self, accessWidth, accessOffset, data):
		if accessOffset < self.outputAddressBase:
			return False
		# Just pretend we wrote it somewhere.
		return True