{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
module Bus() where

import Clash.Prelude

import Peripherals.Ram(Ram, RamLine)
import Machine(Peripherals(..))
import BusTypes(
    BusError(..),
    TransactionSize(..),
    Request(..),
    BusResponse(..),
    BusVal(..),
    ReadResponse(..),
    WriteResponse(..)
  )
import Types(Addr,
             Byte, HalfWord, FullWord, DoubleWord, QuadWord)

alignCheck :: Addr -> TransactionSize -> Bool
alignCheck addr SizeByte       = True
alignCheck addr SizeHalfWord   = addr `mod` 2 == 0
alignCheck addr SizeWord       = addr `mod` 4 == 0
alignCheck addr SizeDoubleWord = addr `mod` 8 == 0
alignCheck addr SizeQuadWord   = addr `mod` 16 == 0

-- ram shoudl start at 0x80000000

-- concatWords :: [Ram -> Addr -> RamLine] -> Ram -> Addr -> RamLine
-- concatWords readers ram baseAddr = foldl (\acc f -> (acc `shiftL` 32) .|. f ram baseAddr) 0 readers

-- read :: Request -> Peripherals -> ReadResponse
-- read (Request addr size) peripherals
--   | not (alignCheck addr size) = ReadError UnAligned
--   | addr >= numBytesInRam      = ReadError UnMapped
--   | otherwise                  =
--     case size of
--       SizeByte       -> BusByte $ fromIntegral $ extractByte (ramRead 0)
--       SizeHalfWord   -> BusHalfWord $ fromIntegral $ (ramRead 0 `shiftL` 8) .|. ramRead 1
--       SizeWord       -> BusWord $ fromIntegral $ concatReads [0..3]
--       SizeDoubleWord -> BusDoubleWord $ fromIntegral $ concatReads [0..7]
--       SizeQuadWord   -> BusQuadWord $ fromIntegral $ concatReads [0..15]
--   where
--     ramRead offset = Peripherals.Ram.read (ram peripherals) (fromIntegral (addr + offset))
--     concatReads offsets = foldl (\acc o -> (acc `shiftL` 8) .|. ramRead o) 0 offsets