asm6809.hs

module ASM6809 where

import Data.ByteString.Builder
import Data.Word
import System.IO

data Instruction =
    NOP
  | ADDA Word8
  | LDA Word8
  | STA Word8

assemble :: Instruction -> [Word8]
assemble NOP = [0x12]
assemble (ADDA w) = [0x8b, w]
assemble (LDA w) = [0x86, w]
assemble (STA w) = [0x97, w]

-- 56 + 43 = 99 (0x63)
program :: [Instruction]
program =
  [ LDA 0x38  -- 56
  , ADDA 0x2b -- 43
  , STA 0x42
  ]

main :: IO ()
main = do
  hSetBuffering stdout (BlockBuffering Nothing)
  hSetBinaryMode stdout True
  let assembled = program >>= assemble
  mapM_ (hPutBuilder stdout . word8) assembled