47 lines
1.3 KiB
Haskell
47 lines
1.3 KiB
Haskell
{-# LANGUAGE TemplateHaskell #-}
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module SixtyFiveOhTwo.Instruction where
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import Control.Monad.State
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import qualified Data.ByteString as B
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import qualified Data.Map.Strict as M
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import Control.Lens
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import Data.Word
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data InstructionState = InstructionState {
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-- The functionTable relates functions to their byte offsets in the compiled code
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_functionTable :: M.Map String Int,
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_bytestring :: B.ByteString
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}
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makeLenses ''InstructionState
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type Instruction = State InstructionState InstructionState
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data AddressingMode =
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Implied |
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Accumulator |
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Immediate Word8 |
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Relative Word8 | -- Signed
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Absolute Word16 |
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AbsoluteX Word16 |
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AbsoluteY Word16 |
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ZeroPage Word8 |
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ZeroPageX Word8 |
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ZeroPageY Word8 |
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ZeroPageIndirect Word8 |
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Indirect Word16 |
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IndirectX Word8 |
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IndirectY Word8
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define :: String -> Instruction -> Instruction
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define name definition = do
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insState <- get
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let insState' = over functionTable (\fT -> M.insert name (B.length $ insState ^. bytestring) fT) insState
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-- TODO: COMBINE THE FUNCTION DEFINITIONS HERE TOO NOT JUST BYTESTRINGS
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return $ execState definition insState'
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adc :: AddressingMode -> Instruction
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adc (Immediate b) = do
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insState <- get
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return $ over bytestring (\bs -> B.append bs (B.pack [0x69, b])) insState |