replace/update relevant fetch types and functions

hs/Fetch.hs

@@ -3,9 +3,8 @@
 
 module Fetch(
   fetchInstruction,
-  fetchInstruction1,
   FetchResult(..),
-  FetchResult1(..)) where
+  ) where
 
 import Clash.Prelude
 import Types(Mem, Addr, Insn)
@@ -22,31 +21,15 @@ import GHC.IO (IO)
 import GHC.Base (Applicative(pure))
 
 data FetchResult  = Instruction Insn
-                  | Misaligned Addr
-
-data FetchResult1  = Instruction1 Insn
                    | InstructionException Exception
 
-fetchInstruction :: KnownNat n => Mem n -> Addr -> FetchResult
-fetchInstruction mem addr =
-  let
-    isWordAligned = addr .&. 3 == 0
-    addrWordAligned = addr `shiftR` 2
-    insn = mem !! addrWordAligned
-    -- TODO : check if instruction is word aligned and create type
-    -- to capture if its not.
-  in
-    case isWordAligned of
-      True -> Instruction insn
-      False -> Misaligned addr
-
-fetchInstruction1 :: Peripherals -> Addr -> IO FetchResult1
-fetchInstruction1 peripherals addr =
+fetchInstruction :: Peripherals -> Addr -> IO FetchResult
+fetchInstruction peripherals addr =
   do
     readReasponse <-Bus.read (BusTypes.Request addr BusTypes.SizeFullWord) peripherals
     case readReasponse of
       Right (BusFullWord insn) ->
-        pure $ Instruction1 insn
+        pure $ Instruction insn
       Left  UnAligned ->
         pure $ InstructionException InstructionAddressMisaligned
       Left  UnMapped ->

hs/Simulation.hs

@@ -19,7 +19,7 @@ import Bus(Peripherals(..))
 import Cpu(
   RISCVCPU(..),
   riscvCPUInit)
-import Fetch(fetchInstruction, FetchResult (Instruction, Misaligned), fetchInstruction1, FetchResult1(..))
+import Fetch(fetchInstruction, FetchResult (..))
 import Isa.Decode(decode)
 
 import Debug.Trace
@@ -40,31 +40,10 @@ data Machine = Machine
   }
   deriving (Generic, Show, Eq, NFDataX)
 
-machine' :: Machine -> Machine
-machine' machine =
-  let
-    machinePeripherals  = peripherals machine
-    machineMem  = ram $ machinePeripherals
-    machineCPU  = cpu machine
-    machinePC   = pc machineCPU
-    cpu' = machineCPU { pc = machinePC + 4 }
-
-  in
-    case (fetchInstruction machineMem machinePC) of
-      Instruction insn ->
-        let binaryInsn = show (bitCoerce insn :: BitVector 32)
-        in trace ("Decoded instruction: " P.++ show opcode
-                  P.++ " | Binary: " P.++ binaryInsn
-                  P.++ " (" P.++ show insn P.++ ")") $
-           machine { cpu = cpu' }
-        where
-          opcode = decode insn
-      Misaligned addr -> undefined
-
-debugInsn :: FetchResult1 -> String
+debugInsn :: FetchResult -> String
 debugInsn fetchResult = 
   case fetchResult of
-    Instruction1 insn ->
+    Instruction insn ->
       "Decoded instruction: " P.++ show opcode
                       P.++ " | Binary: " P.++ binaryInsn
                       P.++ " (" P.++ show insn P.++ ")"
@@ -76,15 +55,13 @@ debugInsn fetchResult =
 simulationLoop :: Int -> Machine -> IO [Machine]
 simulationLoop 0 machine = return [machine]
 simulationLoop n machine = do
-  -- let newState = machine' machine
   let machinePeripherals = peripherals machine
       currPc = pc $ cpu machine
-  fetchResult <- fetchInstruction1 machinePeripherals currPc
+  fetchResult <- fetchInstruction machinePeripherals currPc
   putStrLn $ debugInsn fetchResult
   let pc' = currPc + 4
       cpu' = (cpu machine) { pc = pc' }
       machine' = machine { cpu = cpu' }
-  -- let machine' = machine { cpu = cpu $ machine { pc = pc $ cpu machine + 4 } }
   rest <- simulationLoop (n - 1) machine'
   return (machine : rest)