diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # kempe
 
+## 0.2.0.9
+
+  * Add `armabi` method of exporting Kempe functions, so that `kc` generates
+    suitable code for M1 darwin.
+  * Add `cdecl` subcommand to generate C headers for exported functions
+
 ## 0.2.0.8
 
   * More efficient IR generation; don't copy bytes from a source to the same
@@ -20,7 +26,7 @@
   * Add `absInt` and `chocie` functions to prelude.
   * Add lints for `swap >`, `swap *` &c.
   * Fix bug in typing `>=`, `>`, `!=`
-  
+
 ## 0.2.0.5
 
   * Fix bug in arm control-flow analysis
diff --git a/docs/manual.pdf b/docs/manual.pdf
Binary files a/docs/manual.pdf and b/docs/manual.pdf differ
diff --git a/examples/factorial.kmp b/examples/factorial.kmp
--- a/examples/factorial.kmp
+++ b/examples/factorial.kmp
@@ -17,5 +17,5 @@
            , dup 1 - fac * )
        ]
 
-%foreign cabi fac
-%foreign cabi fac_tailrec
+%foreign armabi fac
+%foreign armabi fac_tailrec
diff --git a/golden/CDecl.hs b/golden/CDecl.hs
new file mode 100644
--- /dev/null
+++ b/golden/CDecl.hs
@@ -0,0 +1,24 @@
+module CDecl ( goldenCDecl
+             ) where
+
+import qualified Data.ByteString.Lazy      as BSL
+import           Data.Text.Lazy.Encoding   (encodeUtf8)
+import           Kempe.File
+import           Language.C.AST
+import           Prettyprinter             (Doc, LayoutOptions (..), PageWidth (..), layoutSmart)
+import           Prettyprinter.Render.Text (renderLazy)
+import           Test.Tasty                (TestTree)
+import           Test.Tasty.Golden         (goldenVsString)
+
+renderBSL :: Doc ann -> BSL.ByteString
+renderBSL = encodeUtf8 . renderLazy . layoutSmart cSettings where
+
+compileOutput :: FilePath
+              -> IO BSL.ByteString
+compileOutput = fmap (renderBSL . prettyHeaders) . cDeclFile
+
+goldenCDecl :: FilePath -- ^ Kempe file
+            -> FilePath -- ^ Golden header file
+            -> TestTree
+goldenCDecl kFp golden =
+    goldenVsString kFp golden (compileOutput kFp)
diff --git a/golden/Golden.hs b/golden/Golden.hs
--- a/golden/Golden.hs
+++ b/golden/Golden.hs
@@ -1,5 +1,6 @@
 module Main (main) where
 
+import           CDecl
 import           Data.Tuple.Extra (uncurry3)
 import           Harness
 import           System.Info      (arch)
@@ -9,6 +10,7 @@
 main = defaultMain $
     testGroup "Golden output tests" $
         fmap (uncurry3 goldenOutput) allGoldens ++ crossTests
+            ++ fmap (uncurry goldenCDecl) headerGoldens
 
 -- These are redundant on arm
 crossTests :: [TestTree]
@@ -16,6 +18,9 @@
     "x86_64"  -> fmap (uncurry3 crossGolden) allGoldens
     "aarch64" -> []
     _         -> error "Test suite must be run on x86_64 or aarch64"
+
+headerGoldens :: [(FilePath, FilePath)]
+headerGoldens = [ ("test/examples/splitmix.kmp", "test/include/splitmix.h") ]
 
 allGoldens :: [(FilePath, FilePath, FilePath)]
 allGoldens =
diff --git a/golden/Harness.hs b/golden/Harness.hs
--- a/golden/Harness.hs
+++ b/golden/Harness.hs
@@ -12,7 +12,6 @@
 import           System.Process             (CreateProcess (env, std_err), StdStream (Inherit), proc, readCreateProcess)
 import           Test.Tasty
 import           Test.Tasty.Golden          (goldenVsString)
-import           Test.Tasty.HUnit           (assertBool, testCase)
 
 data CC = CC
         | ArmCC
diff --git a/kempe.cabal b/kempe.cabal
--- a/kempe.cabal
+++ b/kempe.cabal
@@ -1,6 +1,6 @@
 cabal-version:   3.0
 name:            kempe
-version:         0.2.0.8
+version:         0.2.0.9
 license:         BSD-3-Clause
 license-file:    LICENSE
 copyright:       Copyright: (c) 2020-2021 Vanessa McHale
@@ -17,6 +17,7 @@
     test/examples/*.kmp
     test/golden/*.out
     test/golden/*.ir
+    test/include/*.h
     test/harness/*.c
     examples/*.kmp
     prelude/*.kmp
@@ -59,6 +60,7 @@
         Kempe.Asm.Arm.Trans
         Kempe.Asm.Arm.ControlFlow
         Kempe.Asm.Arm.Linear
+        Language.C.AST
 
     hs-source-dirs:   src
     other-modules:
@@ -77,6 +79,7 @@
         Kempe.Asm.Pretty
         Kempe.IR.Type
         Kempe.IR.Monad
+        Kempe.CGen
         Kempe.Proc.Nasm
         Kempe.Proc.As
         Kempe.Debug
@@ -152,7 +155,8 @@
         optparse-applicative,
         kempe-modules,
         prettyprinter >=1.7.0,
-        bytestring
+        bytestring,
+        text
 
     if impl(ghc >=8.0)
         ghc-options:
@@ -210,7 +214,10 @@
     type:             exitcode-stdio-1.0
     main-is:          Golden.hs
     hs-source-dirs:   golden
-    other-modules:    Harness
+    other-modules:
+        Harness
+        CDecl
+
     default-language: Haskell2010
     ghc-options:      -threaded -rtsopts "-with-rtsopts=-N -K1K" -Wall
     build-depends:
@@ -222,8 +229,9 @@
         temporary,
         filepath,
         tasty-golden,
-        tasty-hunit,
-        extra
+        extra,
+        prettyprinter,
+        text
 
     if impl(ghc >=8.0)
         ghc-options:
diff --git a/lib/numbertheory.kmp b/lib/numbertheory.kmp
--- a/lib/numbertheory.kmp
+++ b/lib/numbertheory.kmp
@@ -35,5 +35,5 @@
 k_gcd : Int Int -- Int
       =: [ gcd ]
 
-%foreign cabi k_gcd
-%foreign cabi is_prime
+%foreign armabi k_gcd
+%foreign armabi is_prime
diff --git a/run/Main.hs b/run/Main.hs
--- a/run/Main.hs
+++ b/run/Main.hs
@@ -4,15 +4,17 @@
 import           Control.Monad             ((<=<))
 import qualified Data.ByteString.Lazy      as BSL
 import           Data.Semigroup            ((<>))
+import qualified Data.Text.Lazy.IO         as TLIO
 import qualified Data.Version              as V
 import           Kempe.AST
 import           Kempe.File
 import           Kempe.Lexer
 import           Kempe.Parser
+import           Language.C.AST
 import           Options.Applicative
 import qualified Paths_kempe               as P
 import           Prettyprinter             (LayoutOptions (LayoutOptions), PageWidth (AvailablePerLine), hardline, layoutSmart)
-import           Prettyprinter.Render.Text (renderIO)
+import           Prettyprinter.Render.Text (putDoc, renderIO, renderLazy)
 import           System.Exit               (ExitCode (ExitFailure), exitWith)
 import           System.IO                 (stdout)
 import           System.Info               (arch)
@@ -24,7 +26,16 @@
              | Compile !FilePath !(Maybe FilePath) !Arch !Bool !Bool !Bool
              | Format !FilePath
              | Lint !FilePath
+             | CDecl !FilePath !(Maybe FilePath)
 
+cdecl :: FilePath -> IO ()
+cdecl = putDoc . (<> hardline) . prettyHeaders <=< cDeclFile
+
+writeCDecl :: FilePath -> FilePath -> IO ()
+writeCDecl fp o = do
+    ds <- cDeclFile fp
+    TLIO.writeFile o (renderLazy $ layoutSmart cSettings $ prettyHeaders ds)
+
 fmt :: FilePath -> IO ()
 fmt = renderIO stdout <=< fmap (render . (<> hardline) . prettyModule) . parsedFp
     where render = layoutSmart settings
@@ -48,6 +59,8 @@
 run (Compile fp Nothing X64 False False True)     = x86File fp
 run (Compile fp Nothing Aarch64 False False True) = armFile fp
 run (Format fp)                                   = fmt fp
+run (CDecl fp Nothing)                            = cdecl fp
+run (CDecl fp (Just o))                           = writeCDecl fp o
 run _                                             = putStrLn "Invalid combination of CLI options. Try kc --help" *> exitWith (ExitFailure 1)
 
 kmpFile :: Parser FilePath
@@ -62,6 +75,9 @@
 lintP :: Parser Command
 lintP = Lint <$> kmpFile
 
+cdeclP :: Parser Command
+cdeclP = CDecl <$> kmpFile <*> outFile
+
 debugSwitch :: Parser Bool
 debugSwitch = switch
     (long "debug"
@@ -96,8 +112,8 @@
     (long "dump-asm"
     <> help "Write assembly (intel syntax) to stdout")
 
-exeFile :: Parser (Maybe FilePath)
-exeFile = optional $ argument str
+outFile :: Parser (Maybe FilePath)
+outFile = optional $ argument str
     (metavar "OUTPUT"
     <> help "File output")
 
@@ -109,10 +125,11 @@
     (command "typecheck" (info tcP (progDesc "Type-check module contents"))
     <> command "lint" (info lintP (progDesc "Lint a file")))
     <|> hsubparser (command "fmt" (info fmtP (progDesc "Pretty-print a Kempe file")) <> internal)
+    <|> hsubparser (command "cdecl" (info cdeclP (progDesc "Generate C headers for exported Kempe code")))
     <|> compileP
     where
         tcP = TypeCheck <$> kmpFile
-        compileP = Compile <$> kmpFile <*> exeFile <*> archFlag <*> debugSwitch <*> irSwitch <*> asmSwitch
+        compileP = Compile <$> kmpFile <*> outFile <*> archFlag <*> debugSwitch <*> irSwitch <*> asmSwitch
 
 wrapper :: ParserInfo Command
 wrapper = info (helper <*> versionMod <*> commandP)
diff --git a/src/Kempe/AST/Size.hs b/src/Kempe/AST/Size.hs
--- a/src/Kempe/AST/Size.hs
+++ b/src/Kempe/AST/Size.hs
@@ -69,11 +69,15 @@
 
 data ABI = Cabi
          | Kabi
+         | Hooked
+         | ArmAbi
          deriving (Eq, Ord, Generic, NFData)
 
 instance Pretty ABI where
-    pretty Cabi = "cabi"
-    pretty Kabi = "kabi"
+    pretty Cabi   = "cabi"
+    pretty Kabi   = "kabi"
+    pretty Hooked = "hooked"
+    pretty ArmAbi = "armabi"
 
 -- machinery for assigning a constructor to a function of its concrete types
 -- (and then curry forward...)
diff --git a/src/Kempe/Asm/Arm/Trans.hs b/src/Kempe/Asm/Arm/Trans.hs
--- a/src/Kempe/Asm/Arm/Trans.hs
+++ b/src/Kempe/Asm/Arm/Trans.hs
@@ -4,13 +4,16 @@
                            ) where
 
 import           Data.Bits          (rotateR, (.&.))
+import qualified Data.ByteString    as BS
 import           Data.Foldable.Ext  (foldMapA)
 import           Data.Int           (Int64)
 import           Data.List          (scanl')
+import           Data.Semigroup     ((<>))
 import           Kempe.AST.Size
 import           Kempe.Asm.Arm.Type
 import           Kempe.IR.Monad
 import qualified Kempe.IR.Type      as IR
+import           System.Info        (arch, os)
 
 irToAarch64 :: SizeEnv -> IR.WriteSt -> [IR.Stmt] -> [Arm AbsReg ()]
 irToAarch64 env w = runWriteM w . foldMapA (irEmit env)
@@ -36,18 +39,33 @@
 popLink :: [Arm AbsReg ()]
 popLink = [Load () LinkReg (Reg StackPtr), AddRC () StackPtr StackPtr 16]
 
+-- darwin on arm requires _ prepended to export
+darwinExport :: BS.ByteString -> BS.ByteString
+darwinExport = case (os, arch) of
+    ("darwin", "aarch64") -> ("_" <>)
+    _                     -> id
+
 irEmit :: SizeEnv -> IR.Stmt -> WriteM [Arm AbsReg ()]
 irEmit _ (IR.Jump l)                    = pure [Branch () l]
 irEmit _ IR.Ret                         = pure [Ret ()]
 irEmit _ (IR.KCall l)                   = pure (pushLink ++ BranchLink () l : popLink) -- TODO: think more?
 irEmit _ (IR.Labeled l)                 = pure [Label () l]
-irEmit _ (IR.WrapKCall Kabi (_, _) n l) = pure $ [BSLabel () n] ++ pushLink ++ [BranchLink () l] ++ popLink ++ [Ret ()]
+irEmit _ (IR.WrapKCall Kabi (_, _) n l) = pure $ [BSLabel () (darwinExport n)] ++ pushLink ++ [BranchLink () l] ++ popLink ++ [Ret ()]
+irEmit _ (IR.WrapKCall Hooked (_, _) n l) =
+    pure $ [MovRR () DataPointer CArg0, BSLabel () n] ++ pushLink ++ [BranchLink () l] ++ popLink ++ [Ret ()]
 irEmit env (IR.WrapKCall Cabi (is, [o]) n l) | all (\i -> size' env i <= 8) is && size' env o <= 8 && length is <= 8 = do
     { let sizes = fmap (size' env) is
     ; let offs = scanl' (+) 0 sizes
     ; let totalSize = sizeStack env is
     ; let argRegs = [CArg0, CArg1, CArg2, CArg3, CArg4, CArg5, CArg6, CArg7]
-    ; pure $ [BSLabel () n] ++ pushLink ++ [LoadLabel () DataPointer "kempe_data", GnuMacro () "calleesave"] ++ zipWith3 (\r sz i -> storeSize sz r (AddRCPlus DataPointer i)) argRegs sizes offs ++ [AddRC () DataPointer DataPointer totalSize, BranchLink () l, loadSize (size' env o) CArg0 (AddRCPlus DataPointer (negate $ size' env o)), GnuMacro () "calleerestore"] ++ popLink ++ [Ret ()]
+    ; pure $ [BSLabel () (darwinExport n)] ++ pushLink ++ [LoadLabel () DataPointer "kempe_data", GnuMacro () "calleesave"] ++ zipWith3 (\r sz i -> storeSize sz r (AddRCPlus DataPointer i)) argRegs sizes offs ++ [AddRC () DataPointer DataPointer totalSize, BranchLink () l, loadSize (size' env o) CArg0 (AddRCPlus DataPointer (negate $ size' env o)), GnuMacro () "calleerestore"] ++ popLink ++ [Ret ()]
+    }
+irEmit env (IR.WrapKCall ArmAbi (is, [o]) n l) | all (\i -> size' env i <= 8) is && size' env o <= 8 && length is <= 8 = do
+    { let sizes = fmap (size' env) is
+    ; let offs = scanl' (+) 0 sizes
+    ; let totalSize = sizeStack env is
+    ; let argRegs = [CArg1, CArg2, CArg3, CArg4, CArg5, CArg6, CArg7]
+    ; pure $ [BSLabel () (darwinExport n)] ++ pushLink ++ [MovRR () DataPointer CArg0, GnuMacro () "calleesave"] ++ zipWith3 (\r sz i -> storeSize sz r (AddRCPlus DataPointer i)) argRegs sizes offs ++ [AddRC () DataPointer DataPointer totalSize, BranchLink () l, loadSize (size' env o) CArg0 (AddRCPlus DataPointer (negate $ size' env o)), GnuMacro () "calleerestore"] ++ popLink ++ [Ret ()]
     }
 irEmit _ (IR.MovMem (IR.Reg r) 8 (IR.Reg r')) =
     pure [Store () (toAbsReg r') (Reg $ toAbsReg r)]
diff --git a/src/Kempe/Asm/X86/Trans.hs b/src/Kempe/Asm/X86/Trans.hs
--- a/src/Kempe/Asm/X86/Trans.hs
+++ b/src/Kempe/Asm/X86/Trans.hs
@@ -127,8 +127,16 @@
     ; let argRegs = [CArg1, CArg2, CArg3, CArg4, CArg5, CArg6]
     ; pure $ [BSLabel () n, MovRL () DataPointer "kempe_data", NasmMacro0 () "calleesave"] ++ zipWith (\r i-> MovAR () (AddrRCPlus DataPointer i) r) argRegs offs ++ [AddRC () DataPointer totalSize, Call () l, MovRA () CRet (AddrRCMinus DataPointer (size' env o)), NasmMacro0 () "calleerestore", Ret ()] -- TODO: bytes on the stack eh
     }
+irEmit env (IR.WrapKCall ArmAbi (is, [o]) n l) | all (\i -> size' env i <= 8) is && size' env o <= 8 && length is <= 6 = do
+    { let offs = scanl' (+) 0 (fmap (size' env) is)
+    ; let totalSize = sizeStack env is
+    ; let argRegs = [CArg2, CArg3, CArg4, CArg5, CArg6]
+    ; pure $ [BSLabel () n, MovRR () DataPointer CArg1, NasmMacro0 () "calleesave"] ++ zipWith (\r i-> MovAR () (AddrRCPlus DataPointer i) r) argRegs offs ++ [AddRC () DataPointer totalSize, Call () l, MovRA () CRet (AddrRCMinus DataPointer (size' env o)), NasmMacro0 () "calleerestore", Ret ()] -- TODO: bytes on the stack eh
+    }
 irEmit _ (IR.WrapKCall Kabi (_, _) n l) =
     pure [BSLabel () n, Call () l, Ret ()]
+irEmit _ (IR.WrapKCall Hooked (_, _) n l) =
+    pure [MovRR () DataPointer CArg1, BSLabel () n, Call () l, Ret ()]
 irEmit _ (IR.MovMem (IR.Reg r) _ (IR.ConstInt8 i)) =
     pure [ MovACi8 () (Reg $ toAbsReg r) i ]
     -- see: https://github.com/cirosantilli/x86-assembly-cheat/blob/master/x86-64/movabs.asm for why we don't do this ^ for words
diff --git a/src/Kempe/CGen.hs b/src/Kempe/CGen.hs
new file mode 100644
--- /dev/null
+++ b/src/Kempe/CGen.hs
@@ -0,0 +1,36 @@
+module Kempe.CGen ( cGen
+                  ) where
+
+import           Data.Maybe     (mapMaybe)
+import           Kempe.AST
+import           Kempe.Name
+import           Language.C.AST
+
+cGen :: Declarations a c (StackType ()) -> [CFunc]
+cGen = mapMaybe cDecl
+
+cDecl :: KempeDecl a c (StackType ()) -> Maybe CFunc
+cDecl ExtFnDecl{}                                        = Nothing
+cDecl TyDecl{}                                           = Nothing
+cDecl FunDecl{}                                          = Nothing
+cDecl (Export _ Cabi (Name n _ (StackType _ [] [])))     = Just (CFunc n [CVoid] CVoid)
+cDecl (Export _ Cabi (Name n _ (StackType _ [] [o])))    = Just (CFunc n [CVoid] (kempeTyToCType o))
+cDecl (Export _ Cabi (Name n _ (StackType _ ins [])))    = Just (CFunc n (kempeTyToCType <$> ins) CVoid)
+cDecl (Export _ Cabi (Name n _ (StackType _ ins [o])))   = Just (CFunc n (kempeTyToCType <$> ins) (kempeTyToCType o))
+cDecl (Export _ Cabi _)                                  = error "Multiple return not suppported :("
+cDecl (Export _ ArmAbi (Name n _ (StackType _ [] [])))   = Just (CFunc n [CVoidPtr] CVoid)
+cDecl (Export _ ArmAbi (Name n _ (StackType _ [] [o])))  = Just (CFunc n [CVoidPtr] (kempeTyToCType o))
+cDecl (Export _ ArmAbi (Name n _ (StackType _ ins [])))  = Just (CFunc n (CVoidPtr : fmap kempeTyToCType ins) CVoid)
+cDecl (Export _ ArmAbi (Name n _ (StackType _ ins [o]))) = Just (CFunc n (CVoidPtr : fmap kempeTyToCType ins) (kempeTyToCType o))
+cDecl (Export _ ArmAbi _)                                = error "Multiple return not suppported :("
+cDecl (Export _ Hooked (Name n _ _))                     = Just (CFunc n [CVoidPtr] CVoid)
+cDecl (Export _ Kabi _)                                  = error "You probably don't want to do this."
+
+kempeTyToCType :: KempeTy a -> CType
+kempeTyToCType (TyBuiltin _ TyInt)  = CInt
+kempeTyToCType (TyBuiltin _ TyBool) = CBool
+kempeTyToCType (TyBuiltin _ TyWord) = CUInt64
+kempeTyToCType (TyBuiltin _ TyInt8) = CInt8
+kempeTyToCType TyVar{}              = error "Don't do that"
+kempeTyToCType TyApp{}              = error "User-defined types cannot be exported :("
+kempeTyToCType TyNamed{}            = error "User-defined types cannot be exported :("
diff --git a/src/Kempe/File.hs b/src/Kempe/File.hs
--- a/src/Kempe/File.hs
+++ b/src/Kempe/File.hs
@@ -2,6 +2,8 @@
                   , warnFile
                   , dumpMono
                   , dumpTyped
+                  , dumpCDecl
+                  , cDeclFile
                   , irFile
                   , x86File
                   , armFile
@@ -16,6 +18,7 @@
 import           Control.Applicative       ((<|>))
 import           Control.Composition       ((.*))
 import           Control.Exception         (Exception, throwIO)
+import           Control.Monad             ((<=<))
 import           Data.Bifunctor            (bimap)
 import           Data.Functor              (void)
 import           Data.Semigroup            ((<>))
@@ -25,6 +28,7 @@
 import           Kempe.AST
 import qualified Kempe.Asm.Arm.Type        as Arm
 import qualified Kempe.Asm.X86.Type        as X86
+import           Kempe.CGen
 import           Kempe.Check.Lint
 import           Kempe.Check.Pattern
 import           Kempe.Check.TopLevel
@@ -37,6 +41,7 @@
 import qualified Kempe.Proc.Nasm           as Nasm
 import           Kempe.Shuttle
 import           Kempe.TyAssign
+import           Language.C.AST
 import           Prettyprinter             (Doc, hardline)
 import           Prettyprinter.Render.Text (putDoc)
 
@@ -54,6 +59,15 @@
 
 yeetIO :: Exception e => Either e a -> IO a
 yeetIO = either throwIO pure
+
+cDeclFile :: FilePath -> IO [CFunc]
+cDeclFile fp = do
+    (i, m) <- parseProcess fp
+    (mTyped, _) <- yeetIO $ runTypeM i (assignModule m)
+    pure $ cGen mTyped
+
+dumpCDecl :: FilePath -> IO ()
+dumpCDecl = putDoc . prettyHeaders <=< cDeclFile
 
 dumpTyped :: FilePath -> IO ()
 dumpTyped fp = do
diff --git a/src/Kempe/Lexer.x b/src/Kempe/Lexer.x
--- a/src/Kempe/Lexer.x
+++ b/src/Kempe/Lexer.x
@@ -111,6 +111,8 @@
         "%foreign"               { mkKw KwForeign }
         "cabi"                   { mkKw KwCabi }
         "kabi"                   { mkKw KwKabi }
+        "hooked"                 { mkKw KwHooked }
+        "armabi"                 { mkKw KwArmAbi }
 
         -- builtin
         dip                      { mkBuiltin BuiltinDip }
@@ -288,6 +290,8 @@
              | KwForeign
              | KwCabi
              | KwKabi
+             | KwHooked
+             | KwArmAbi
              deriving (Generic, NFData)
 
 instance Pretty Keyword where
@@ -299,6 +303,8 @@
     pretty KwForeign = "%foreign"
     pretty KwCabi    = "cabi"
     pretty KwKabi    = "kabi"
+    pretty KwHooked  = "hooked"
+    pretty KwArmAbi  = "armabi"
 
 data Builtin = BuiltinBool
              | BuiltinBoolLit { bool :: !Bool }
diff --git a/src/Kempe/Parser.y b/src/Kempe/Parser.y
--- a/src/Kempe/Parser.y
+++ b/src/Kempe/Parser.y
@@ -89,6 +89,8 @@
     foreign { TokKeyword $$ KwForeign }
     cabi { TokKeyword $$ KwCabi }
     kabi { TokKeyword $$ KwKabi }
+    hooked { TokKeyword $$ KwHooked }
+    armabi { TokKeyword $$ KwArmAbi }
     import { TokKeyword $$ KwImport }
 
     dip { TokBuiltin $$ BuiltinDip }
@@ -139,6 +141,8 @@
 ABI :: { ABI }
     : cabi { Cabi }
     | kabi { Kabi }
+    | hooked { Hooked }
+    | armabi { ArmAbi }
 
 Decl :: { KempeDecl AlexPosn AlexPosn AlexPosn }
      : TyDecl { $1 }
diff --git a/src/Language/C/AST.hs b/src/Language/C/AST.hs
new file mode 100644
--- /dev/null
+++ b/src/Language/C/AST.hs
@@ -0,0 +1,62 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module Language.C.AST ( CType (..)
+                      , CFunc (..)
+                      , prettyHeaders
+                      , cSettings
+                      ) where
+
+import           Data.Semigroup    ((<>))
+import qualified Data.Set          as S
+import qualified Data.Text         as T
+import           Prettyprinter     (Doc, LayoutOptions (..), PageWidth (..), Pretty (..), tupled, (<+>))
+import           Prettyprinter.Ext
+
+cSettings :: LayoutOptions
+cSettings = LayoutOptions $ AvailablePerLine 180 0.8
+
+data CHeader = StdBool -- ^ @stdbool.h@
+             | StdInt -- ^ @stdint.h@
+             deriving (Eq, Ord)
+
+prettyInclude :: CHeader -> Doc ann
+prettyInclude StdBool = "#include <stdbool.h>"
+prettyInclude StdInt  = "#include <stdint.h>"
+
+data CType = CInt
+           | CBool
+           | CUInt64
+           | CInt8
+           | CVoid
+           | CVoidPtr
+           -- ADTs etc.
+
+data CFunc = CFunc !T.Text [CType] CType
+
+prettyHeaders :: [CFunc] -> Doc ann
+prettyHeaders es =
+    let hs = foldMap mentionedFunc es
+        in prettyLines (fmap prettyInclude (S.toList hs))
+            <#> prettyLines (fmap pretty es)
+
+mentioned :: CType -> S.Set CHeader
+mentioned CInt     = mempty
+mentioned CBool    = S.singleton StdBool
+mentioned CUInt64  = S.singleton StdInt
+mentioned CVoid    = mempty
+mentioned CVoidPtr = mempty
+mentioned CInt8    = S.singleton StdInt
+
+mentionedFunc :: CFunc -> S.Set CHeader
+mentionedFunc (CFunc _ args ret) = foldMap mentioned (ret : args)
+
+instance Pretty CType where
+    pretty CInt     = "int"
+    pretty CBool    = "bool"
+    pretty CUInt64  = "uint64_t"
+    pretty CVoid    = "void"
+    pretty CVoidPtr = "void*"
+    pretty CInt8    = "int8_t"
+
+instance Pretty CFunc where
+    pretty (CFunc fname args retType) = "extern" <+> pretty retType <+> pretty fname <+> tupled (pretty <$> args) <> ";"
diff --git a/test/examples/bool.kmp b/test/examples/bool.kmp
--- a/test/examples/bool.kmp
+++ b/test/examples/bool.kmp
@@ -15,5 +15,5 @@
 nor : Bool Bool -- Bool
     =: [ || not ]
 
-%foreign cabi not
-%foreign cabi eq
+%foreign armabi not
+%foreign armabi eq
diff --git a/test/examples/const.kmp b/test/examples/const.kmp
--- a/test/examples/const.kmp
+++ b/test/examples/const.kmp
@@ -1,4 +1,4 @@
 id_int : Int -- Int
        =: [ ]
 
-%foreign cabi id_int
+%foreign armabi id_int
diff --git a/test/examples/splitmix.kmp b/test/examples/splitmix.kmp
--- a/test/examples/splitmix.kmp
+++ b/test/examples/splitmix.kmp
@@ -8,4 +8,4 @@
 from_seed : Word -- Word
           =: [ next dip(drop) ]
 
-%foreign cabi from_seed
+%foreign armabi from_seed
diff --git a/test/harness/bool.c b/test/harness/bool.c
--- a/test/harness/bool.c
+++ b/test/harness/bool.c
@@ -1,11 +1,13 @@
 #include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 
-extern bool not(bool);
-extern bool eq(bool, bool);
+extern bool not(void*, bool);
+extern bool eq(void*, bool, bool);
 
 int main(int argc, char *argv[]) {
-    printf("%d\n", not(true));
-    printf("%d\n", not(false));
-    printf("%d", eq(true, false));
+    void* kptr = malloc(32 * 1024);
+    printf("%d\n", not(kptr, true));
+    printf("%d\n", not(kptr, false));
+    printf("%d", eq(kptr, true, false));
 }
diff --git a/test/harness/const.c b/test/harness/const.c
--- a/test/harness/const.c
+++ b/test/harness/const.c
@@ -1,7 +1,9 @@
 #include <stdio.h>
+#include <stdlib.h>
 
-extern int id_int(int);
+extern int id_int(void*, int);
 
 int main(int argc, char *argv[]) {
-    printf("%d", id_int(3));
+    void* kptr = malloc(32 * 1024);
+    printf("%d", id_int(kptr, 3));
 }
diff --git a/test/harness/factorial.c b/test/harness/factorial.c
--- a/test/harness/factorial.c
+++ b/test/harness/factorial.c
@@ -1,9 +1,11 @@
 #include <stdio.h>
+#include <stdlib.h>
 
-extern int fac_tailrec(int);
-extern int fac(int);
+extern int fac_tailrec(void*, int);
+extern int fac(void*, int);
 
 int main(int argc, char *argv[]) {
-    printf("%d\n", fac_tailrec(3));
-    printf("%d", fac(3));
+    void* kptr = malloc(32 * 1024);
+    printf("%d\n", fac_tailrec(kptr, 3));
+    printf("%d", fac(kptr, 3));
 }
diff --git a/test/harness/numbertheory.c b/test/harness/numbertheory.c
--- a/test/harness/numbertheory.c
+++ b/test/harness/numbertheory.c
@@ -1,11 +1,13 @@
 #include <stdbool.h>
 #include <stdio.h>
+#include <stdlib.h>
 
-extern int k_gcd(int, int);
-extern bool is_prime(int);
+extern int k_gcd(void*, int, int);
+extern bool is_prime(void*, int);
 
 int main(int argc, char *argv[]) {
-    printf("%d\n", is_prime(37));
-    printf("%d\n", is_prime(36));
-    printf("%d", k_gcd(21, 35));
+    void* kptr = malloc(32 * 1024);
+    printf("%d\n", is_prime(kptr, 37));
+    printf("%d\n", is_prime(kptr, 36));
+    printf("%d", k_gcd(kptr, 21, 35));
 }
diff --git a/test/harness/splitmix.c b/test/harness/splitmix.c
--- a/test/harness/splitmix.c
+++ b/test/harness/splitmix.c
@@ -1,8 +1,10 @@
 #include <stdint.h>
 #include <stdio.h>
+#include <stdlib.h>
 
-extern uint64_t from_seed(uint64_t);
+extern uint64_t from_seed(void*, uint64_t);
 
 int main(int argc, char *argv[]) {
-    printf("%u", (unsigned int) from_seed(3012512025));
+    void* kptr = malloc(32 * 1024);
+    printf("%u", (unsigned int) from_seed(kptr, 3012512025));
 }
diff --git a/test/include/splitmix.h b/test/include/splitmix.h
new file mode 100644
--- /dev/null
+++ b/test/include/splitmix.h
@@ -0,0 +1,2 @@
+#include <stdint.h>
+extern uint64_t from_seed (void*, uint64_t);