mima-tools/src/Mima/State.hs
2019-11-07 16:46:21 +00:00

192 lines
6.9 KiB
Haskell

{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE RecordWildCards #-}
module Mima.State
(
-- * Memory
MimaMemory
, readAt
, writeAt
-- ** Querying
, addressRange
, sparseAddressRange
-- ** Converting
, wordsToMemory
, memoryToWords
-- * State
, MimaState(..)
, initialState
, AbortReason(..)
, step
, run
, runN
) where
import Data.Bits
import qualified Data.Map.Strict as Map
import qualified Data.Text as T
import Mima.Instruction
import Mima.Util
import Mima.Word
newtype MimaMemory = MimaMemory (Map.Map MimaAddress MimaWord)
deriving (Show)
addressRange :: MimaMemory -> [MimaAddress]
addressRange (MimaMemory m) =
case fst <$> Map.lookupMax m of
Nothing -> []
Just maxAddr -> [minBound..maxAddr]
sparseAddressRange :: MimaMemory -> [MimaAddress]
sparseAddressRange (MimaMemory m) = Map.keys m
wordsToMemory :: [MimaWord] -> MimaMemory
wordsToMemory = MimaMemory
. Map.filter (/= zeroBits)
. Map.fromAscList
. zip [minBound..]
memoryToWords :: MimaMemory -> [MimaWord]
memoryToWords mem = map (\addr -> readAt addr mem) $ addressRange mem
{-
addrWordLegend :: T.Text
addrWordLegend = "SO: Small Opcode (bits 23-20) LO: Large Opcode (bits 19-16)\n"
<> "Addr (decimal) - Word ( decimal|SO,LO, Addr) - Instruction\n"
addrWordToText :: MimaAddress -> MimaWord -> T.Text
addrWordToText addr word =
let separator = " - "
addrText = addrToHex addr <> " (" <> addrToDec addr <> ")"
wordSplit = toDec 2 (upperOpcode word) <> ","
<> toDec 2 (lowerOpcode word) <> ","
<> addrToDec (address word)
wordText = wordToHex word <> " (" <> wordToDec word <> "|" <> wordSplit <> ")"
instrText = case wordToInstruction word of
Left _ -> ""
Right i -> separator <> toText i
in addrText <> separator <> wordText <> instrText
memoryToText :: Bool -> MimaMemory -> T.Text
memoryToText sparse mem@(MimaMemory m)
= (addrWordLegend <>)
$ T.intercalate "\n"
$ map (\addr -> addrWordToText addr (readAt addr mem))
$ addresses sparse
where
addresses False = addressRange mem
addresses True = Map.keys m
-}
readAt :: MimaAddress -> MimaMemory -> MimaWord
readAt addr (MimaMemory m) = Map.findWithDefault zeroBits addr m
writeAt :: MimaAddress -> MimaWord -> MimaMemory -> MimaMemory
writeAt addr word (MimaMemory m)
| word == zeroBits = MimaMemory $ Map.delete addr m
| otherwise = MimaMemory $ Map.insert addr word m
data MimaState = MimaState
{ msIAR :: !MimaAddress
, msACC :: !MimaWord
, msRA :: !MimaAddress
, msSP :: !MimaAddress
, msFP :: !MimaAddress
, msMemory :: !MimaMemory
} deriving (Show)
-- | A possible initial MiMa state, where every register is
-- zeroed. Thus, execution starts at address 0x00000.
initialState :: MimaMemory -> MimaState
initialState mem = MimaState
{ msIAR = zeroBits
, msACC = zeroBits
, msRA = zeroBits
, msSP = zeroBits
, msFP = zeroBits
, msMemory = mem
}
data AbortReason = Halted | InvalidInstruction T.Text | InvalidNextIarAddress
deriving (Show)
instance ToText AbortReason where
toText Halted = "Halted"
toText (InvalidInstruction t) = "Invalid instruction: " <> t
toText InvalidNextIarAddress = "Can't increment IAR: Invalid next address"
incrementIAR :: MimaState -> Either AbortReason MimaState
incrementIAR ms =
let addr = msIAR ms
in if addr >= maxBound
then Left InvalidNextIarAddress
else Right ms{msIAR = succ addr}
wordToInstruction' :: MimaWord -> Either AbortReason Instruction
wordToInstruction' word =
case wordToInstruction word of
Right instruction -> Right instruction
Left errorMsg -> Left $ InvalidInstruction errorMsg
step :: MimaState -> Either AbortReason MimaState
step ms = do
let word = readAt (msIAR ms) (msMemory ms)
ms' <- incrementIAR ms
instruction <- wordToInstruction' word
case instruction of
(SmallInstruction so lv) -> pure $ doSmallOpcode so lv ms'
(LargeInstruction lo sv) -> doLargeOpcode lo sv ms'
doSmallOpcode :: SmallOpcode -> LargeValue -> MimaState -> MimaState
doSmallOpcode LDC lv ms@MimaState{..} = ms{msACC = largeValueToWord lv}
doSmallOpcode LDV addr ms@MimaState{..} = ms{msACC = readAt addr msMemory}
doSmallOpcode STV addr ms@MimaState{..} = ms{msMemory = writeAt addr msACC msMemory}
doSmallOpcode ADD addr ms@MimaState{..} = ms{msACC = addWords msACC $ readAt addr msMemory}
doSmallOpcode AND addr ms@MimaState{..} = ms{msACC = msACC .&. readAt addr msMemory}
doSmallOpcode OR addr ms@MimaState{..} = ms{msACC = msACC .|. readAt addr msMemory}
doSmallOpcode XOR addr ms@MimaState{..} = ms{msACC = msACC `xor` readAt addr msMemory}
doSmallOpcode EQL addr ms@MimaState{..} = ms{msACC = boolToWord $ msACC == readAt addr msMemory}
doSmallOpcode JMP addr ms@MimaState{..} = ms{msIAR = addr}
doSmallOpcode JMN addr ms@MimaState{..} = if topBit msACC then ms{msIAR = addr} else ms
doSmallOpcode LDIV addr ms@MimaState{..} =
let indirAddr = getAddress $ readAt addr msMemory
in ms{msACC = readAt indirAddr msMemory}
doSmallOpcode STIV addr ms@MimaState{..} =
let indirAddr = getAddress $ readAt addr msMemory
in ms{msMemory = writeAt indirAddr msACC msMemory}
doSmallOpcode CALL addr ms@MimaState{..} = ms{msRA = msIAR, msIAR = addr}
doSmallOpcode LDVR addr ms@MimaState{..} = ms{msACC = readAt (addLargeValues msSP addr) msMemory}
doSmallOpcode STVR addr ms@MimaState{..} = ms{msMemory = writeAt (addLargeValues msSP addr) msACC msMemory}
doLargeOpcode :: LargeOpcode -> SmallValue -> MimaState -> Either AbortReason MimaState
doLargeOpcode HALT _ _ = Left Halted
doLargeOpcode NOT _ ms@MimaState{..} = pure ms{msACC = complement msACC}
doLargeOpcode RAR _ ms@MimaState{..} = pure ms{msACC = rotateR msACC 1}
doLargeOpcode RET _ ms@MimaState{..} = pure ms{msIAR = msRA}
doLargeOpcode LDRA _ ms@MimaState{..} = pure ms{msACC = largeValueToWord msRA}
doLargeOpcode STRA _ ms@MimaState{..} = pure ms{msRA = getAddress msACC}
doLargeOpcode LDSP _ ms@MimaState{..} = pure ms{msACC = largeValueToWord msSP}
doLargeOpcode STSP _ ms@MimaState{..} = pure ms{msSP = getAddress msACC}
doLargeOpcode LDFP _ ms@MimaState{..} = pure ms{msACC = largeValueToWord msFP}
doLargeOpcode STFP _ ms@MimaState{..} = pure ms{msFP = getAddress msACC}
doLargeOpcode ADC sv ms@MimaState{..} = pure ms{msACC = addWords msACC $ signedSmallValueToWord sv}
run :: MimaState -> (MimaState, AbortReason, Integer)
run ms = helper 0 ms
where
helper completed s =
case step s of
Left e -> (s, e, completed)
Right s' -> helper (completed + 1) s'
runN :: Integer -> MimaState -> (MimaState, Maybe AbortReason, Integer)
runN n ms = helper 0 ms
where
helper completed s =
if completed >= n
then (s, Nothing, completed)
else case step s of
Left e -> (s, Just e, completed)
Right s' -> helper (completed + 1) s'