{-# LANGUAGE TemplateHaskell #-}

-- This module is aimed at testing a naive use-case of 
-- the instantiation mechanism

-- We'll build a system which uses four single-adder components connected
-- sequentially to add four units to the values of the input signal

module SeqAddFour where

import ForSyDe.Deep
import Data.Int

-- A process function which adds one to its input
addOnef :: ProcFun (Int32 -> Int32)
addOnef = $(newProcFun [d|addOnef :: Int32 -> Int32 
                          addOnef n = n + 1     |])

-- System function (or process) which uses addOnef
addOneProc :: Signal Int32 -> Signal Int32
addOneProc = mapSY "addOne" addOnef


-- System definition associated to the system function
addOneSysDef :: SysDef (Signal Int32 -> Signal Int32)
addOneSysDef = newSysDef addOneProc "addOne" ["in1"] ["out1"]


-- Finally, we create the sequential add four system function
addFour :: Signal Int32 -> Signal Int32
addFour = instantiate "addOne3" addOneSysDef .
          instantiate "addOne2" addOneSysDef .
          instantiate "addOne1" addOneSysDef .
          instantiate "addOne0" addOneSysDef

-- We build the system
addFourSys :: SysDef (Signal Int32 -> Signal Int32)
addFourSys = newSysDef addFour "addFour" ["in1"] ["out1"]

-- we simulate the system
simAddFour :: [Int32] -> [Int32]
simAddFour = simulate addFourSys

-- we generate VHDL
createVHDL = writeVHDL addFourSys