145 lines
6.7 KiB
Haskell
145 lines
6.7 KiB
Haskell
module VirtualMachine.Instruction where
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import Data.Char (chr)
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import Data.Word (Word8)
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import Control.Monad.Except (throwError)
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import Control.Monad.Trans (lift, liftIO)
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import Control.Monad.Trans.Except (ExceptT, except)
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import qualified Data.Map as M
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import qualified Data.Sequence as S
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import VirtualMachine.VM (Op(..), Machine, push, pop, forward, getAt, getPc, getFp, getStackSize, setPc, setFp, setHalt)
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type Params = [Int]
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type Pops = [Int]
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type Pushes = S.Seq Int
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data Instruction = Simple { _op :: Op, _noParams :: Int, _noPops :: Int, _sAction :: Params -> Pops -> Pushes }
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| Complex { _op :: Op, _noParams :: Int, _noPops :: Int, _cAction :: Params -> Pops -> ExceptT String Machine () }
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instance Show Instruction where
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show (Simple op noParams noPops _) = (show op) ++ "(S," ++ (show noParams) ++ "," ++ (show noPops) ++ ")"
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show (Complex op noParams noPops _) = (show op) ++ "(C," ++ (show noParams) ++ "," ++ (show noPops) ++ ")"
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data Unit = Instr { _instr :: Instruction }
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| Byte { _byte :: Word8 }
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deriving (Show)
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instructions :: [Instruction]
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instructions = [ Simple { _op = Nop, _noParams = 0, _noPops = 0, _sAction = (\_ _ -> S.empty) }
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, Simple { _op = Push, _noParams = 1, _noPops = 0, _sAction = (\params _ -> S.fromList params) }
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, Simple { _op = Pop, _noParams = 0, _noPops = 1, _sAction = (\_ _ -> S.empty) }
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, Simple { _op = Dup, _noParams = 0, _noPops = 1, _sAction = (\_ [x] -> S.fromList [x, x]) }
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, Simple { _op = Swap, _noParams = 0, _noPops = 2, _sAction = (\_ [x, y] -> S.fromList [y, x]) }
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, Simple { _op = Add, _noParams = 0, _noPops = 2, _sAction = (\_ [x, y] -> S.fromList [y + x]) }
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, Simple { _op = Sub, _noParams = 0, _noPops = 2, _sAction = (\_ [x, y] -> S.fromList [y - x]) }
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, Simple { _op = Mul, _noParams = 0, _noPops = 2, _sAction = (\_ [x, y] -> S.fromList [y * x]) }
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, Simple { _op = Div, _noParams = 0, _noPops = 2, _sAction = (\_ [x, y] -> S.fromList [y `div` x]) }
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, Simple { _op = Neg, _noParams = 0, _noPops = 1, _sAction = (\_ [x] -> S.fromList [-x]) }
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, Simple { _op = Not, _noParams = 0, _noPops = 1, _sAction = (\_ [x] -> S.fromList [if x /= 0 then 0 else 1]) }
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, Complex { _op = Halt, _noParams = 0, _noPops = 0, _cAction = halt }
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, Complex { _op = Call, _noParams = 1, _noPops = 0, _cAction = call }
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, Complex { _op = Ret, _noParams = 0, _noPops = 0, _cAction = ret }
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, Complex { _op = Jmp, _noParams = 1, _noPops = 0, _cAction = jump }
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, Complex { _op = Je, _noParams = 1, _noPops = 1, _cAction = jumpIf (==) }
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, Complex { _op = Jne, _noParams = 1, _noPops = 1, _cAction = jumpIf (/=) }
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, Complex { _op = Jg, _noParams = 1, _noPops = 1, _cAction = jumpIf (>) }
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, Complex { _op = Jl, _noParams = 1, _noPops = 1, _cAction = jumpIf (<) }
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, Complex { _op = Jge, _noParams = 1, _noPops = 1, _cAction = jumpIf (>=) }
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, Complex { _op = Jle, _noParams = 1, _noPops = 1, _cAction = jumpIf (<=) }
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, Complex { _op = Ld, _noParams = 1, _noPops = 0, _cAction = load }
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, Complex { _op = In, _noParams = 0, _noPops = 0, _cAction = niy In }
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, Complex { _op = Out, _noParams = 0, _noPops = 1, _cAction = output }
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, Complex { _op = Clr, _noParams = 1, _noPops = 0, _cAction = clear }
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]
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instructionByOp :: M.Map Op Instruction
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instructionByOp = M.fromList $ map (\i -> (_op i, i)) instructions
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halt :: Params -> Pops -> ExceptT String Machine ()
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halt _ _ = lift $ do
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setHalt True
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return ()
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call :: Params -> Pops -> ExceptT String Machine ()
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call (addr:_) _ = lift $ do
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fp <- getFp
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fp' <- getStackSize
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retAddr <- getPc >>= return . (+2)
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push [retAddr, fp]
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setPc addr
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setFp fp'
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return ()
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call [] _ = throwError "Address excepted"
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ret :: Params -> Pops -> ExceptT String Machine ()
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ret _ _ = do
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fp <- lift getFp
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stackSize <- lift getStackSize
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fp' <- getAt (stackSize - fp - 1) "Cannot determine previous frame pointer (fp)"
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retAddr <- getAt (stackSize - fp - 2) "Cannot determine return address"
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if stackSize - fp == 2
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then lift $ do
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_ <- pop $ stackSize - fp
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return ()
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else lift $ do
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retVal <- pop 1
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_ <- pop $ stackSize - fp - 1
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push retVal
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return ()
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lift $ setFp fp'
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lift $ setPc retAddr
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return ()
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jump :: Params -> Pops -> ExceptT String Machine ()
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jump (addr:_) _ = lift $ do
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setPc addr
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return ()
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jump [] _ = throwError "Address expected"
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jumpIf :: (Int -> Int -> Bool) -> Params -> Pops -> ExceptT String Machine ()
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jumpIf p (addr:_) (top:_) = lift $ do
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pc <- getPc
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setPc $ if top `p` 0 then addr else pc + 2
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return ()
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jumpIf _ [] _ = throwError "Address expected"
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jumpIf _ _ [] = throwError "Empty stack - nothing to compare"
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output :: Params -> Pops -> ExceptT String Machine ()
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output _ (char:_) = lift $ do
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liftIO $ putStr $ [chr char]
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forward 1
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return ()
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output _ [] = except $ Left $ "Empty stack - nothing to output"
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load :: Params -> Pops -> ExceptT String Machine ()
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load (index:_) _ = do
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fp <- lift getFp
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stackSize <- lift getStackSize
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val <- getAt (stackSize - fp + index) ("Index " ++ (show index) ++ " out of stack bounds")
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lift $ push [val]
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lift $ forward 2
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return ()
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load [] _ = throwError "Local parameter index expected"
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niy :: Op -> Params -> Pops -> ExceptT String Machine ()
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niy op _ _ = do
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pc <- lift getPc
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throwError $ "Instruction '" ++ (show op) ++ "' ("++ (show $ pc) ++") is not implemented yet"
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clear :: Params -> Pops -> ExceptT String Machine ()
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clear (count:_) _ = lift $ do
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top <- pop 1
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_ <- pop count
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push top
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forward 2
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return ()
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clear [] _ = except $ Left "Number of elements to be cleaned expected" |