diff --git a/TODO b/TODO
index 6327ff2..ef7c324 100644
--- a/TODO
+++ b/TODO
@@ -15,16 +15,15 @@
 - Format error messages.
 - Return non-zero error code on errors.
 
-# Built-in
-
-- Implement printc (with int argument).
-- Implement exit() as standalone function.
-
 # Register allocation
 
 - Temporary variables always use the same register, t0. Allocate registers for
   temporaries.
 
+# Prarsing and abstract syntax tree
+
+- Parse signed hexadecimal numbers.
+
 # Other
 
 - Type analysis.
diff --git a/lib/Language/Elna/Backend/Allocator.hs b/lib/Language/Elna/Backend/Allocator.hs
index 9ad849e..1ffc85d 100644
--- a/lib/Language/Elna/Backend/Allocator.hs
+++ b/lib/Language/Elna/Backend/Allocator.hs
@@ -36,6 +36,8 @@ allocate MachineConfiguration{..} = fmap function
         SubtractionQuadruple (operand operand1) (operand operand2) (Store temporaryRegister)
     quadruple (NegationQuadruple operand1 _) =
         NegationQuadruple (operand operand1) (Store temporaryRegister)
+    quadruple (ProductQuadruple operand1 operand2 _) =
+        ProductQuadruple (operand operand1) (operand operand2) (Store temporaryRegister)
     operand :: Operand Variable -> Operand (Store r)
     operand (IntOperand x) = IntOperand x
     operand (VariableOperand _) = VariableOperand (Store temporaryRegister)
diff --git a/lib/Language/Elna/Backend/Intermediate.hs b/lib/Language/Elna/Backend/Intermediate.hs
index 01a026b..e7c66cf 100644
--- a/lib/Language/Elna/Backend/Intermediate.hs
+++ b/lib/Language/Elna/Backend/Intermediate.hs
@@ -30,11 +30,11 @@ data Quadruple v
     | AddQuadruple (Operand v) (Operand v) v
     | SubtractionQuadruple (Operand v) (Operand v) v
     | NegationQuadruple (Operand v) v
+    | ProductQuadruple (Operand v) (Operand v) v
     {-| GoToQuadruple Label
     | AssignQuadruple Operand Variable
     | ArrayQuadruple Variable Operand Variable
     | ArrayAssignQuadruple Operand Operand Variable
-    | ProductQuadruple Operand Operand Variable
     | DivisionQuadruple Operand Operand Variable
     | EqualQuadruple Operand Operand Label
     | NonEqualQuadruple Operand Operand Label
diff --git a/lib/Language/Elna/Frontend/AST.hs b/lib/Language/Elna/Frontend/AST.hs
index 738ddcc..4c1c20b 100644
--- a/lib/Language/Elna/Frontend/AST.hs
+++ b/lib/Language/Elna/Frontend/AST.hs
@@ -12,10 +12,12 @@ module Language.Elna.Frontend.AST
     , Literal(..)
     ) where
 
+import Data.Char (chr)
 import Data.Int (Int32)
 import Data.List (intercalate)
-import Data.Word ({-Word16, -}Word32)
+import Data.Word (Word8, Word32)
 import Language.Elna.Location (Identifier(..), showArrayType)
+import Numeric (showHex)
 
 newtype Program = Program [Declaration]
     deriving Eq
@@ -67,8 +69,8 @@ data Statement
     = EmptyStatement
     {-| AssignmentStatement VariableAccess Expression
     | IfStatement Condition Statement (Maybe Statement)
-    | WhileStatement Condition Statement
-    | CompoundStatement [Statement]-}
+    | WhileStatement Condition Statement -}
+    | CompoundStatement [Statement]
     | CallStatement Identifier [Expression]
     deriving Eq
 
@@ -83,9 +85,9 @@ instance Show Statement
         , maybe "" ((<> " else ") . show) else'
         ]
     show (WhileStatement expression statement) =
-        concat ["while (", show expression, ") ", show statement, ";"]
+        concat ["while (", show expression, ") ", show statement, ";"]-}
     show (CompoundStatement statements) =
-        concat ["{\n", unlines (show <$> statements), " }"]-}
+        concat ["{\n", unlines (show <$> statements), " }"]
     show (CallStatement name parameters) = show name <> "("
         <> intercalate ", " (show <$> parameters) <> ")"
 
@@ -93,22 +95,18 @@ data VariableDeclaration =
     VariableDeclaration Identifier TypeExpression
     deriving Eq
 
-newtype Literal
+data Literal
     = IntegerLiteral Int32
-    {- | HexadecimalLiteral Int32
-    | CharacterLiteral Word16
-    | BooleanLiteral Bool -}
+    | HexadecimalLiteral Int32
+    | CharacterLiteral Word8
     deriving Eq
 
 instance Show Literal
   where
     show (IntegerLiteral integer) = show integer
-    {- show (HexadecimalLiteral integer) = '0' : 'x' : showHex integer ""
+    show (HexadecimalLiteral integer) = '0' : 'x' : showHex integer ""
     show (CharacterLiteral character) =
         '\'' : chr (fromEnum character) : ['\'']
-    show (BooleanLiteral boolean)
-        | boolean = "true"
-        | otherwise = "false" -}
 
 instance Show VariableDeclaration
   where
@@ -120,8 +118,8 @@ data Expression
     | SumExpression Expression Expression
     | SubtractionExpression Expression Expression
     | NegationExpression Expression
-{-    | VariableExpression VariableAccess
     | ProductExpression Expression Expression
+{-    | VariableExpression VariableAccess
     | DivisionExpression Expression Expression -}
     deriving Eq
 
@@ -131,13 +129,10 @@ instance Show Expression
     show (SumExpression lhs rhs) = concat [show lhs, " + ", show rhs]
     show (SubtractionExpression lhs rhs) = concat [show lhs, " - ", show rhs]
     show (NegationExpression negation) = '-' : show negation
-    {- show (VariableExpression variable) = show variable
     show (ProductExpression lhs rhs) = concat [show lhs, " * ", show rhs]
+    {- show (VariableExpression variable) = show variable
     show (DivisionExpression lhs rhs) = concat [show lhs, " / ", show rhs] -}
 {-
-import Data.Char (chr)
-import Numeric (showHex)
-
 data VariableAccess
     = VariableAccess Identifier
     | ArrayAccess VariableAccess Expression
diff --git a/lib/Language/Elna/Frontend/NameAnalysis.hs b/lib/Language/Elna/Frontend/NameAnalysis.hs
index 2915331..dc39826 100644
--- a/lib/Language/Elna/Frontend/NameAnalysis.hs
+++ b/lib/Language/Elna/Frontend/NameAnalysis.hs
@@ -144,11 +144,11 @@ expression globalTable (AST.SubtractionExpression lhs rhs)
     >> expression globalTable rhs
 expression globalTable (AST.NegationExpression negation) =
     expression globalTable negation
-{- expression globalTable (AST.VariableExpression variableExpression) =
-    variableAccess globalTable variableExpression
 expression globalTable (AST.ProductExpression lhs rhs)
     = expression globalTable lhs
     >> expression globalTable rhs
+{- expression globalTable (AST.VariableExpression variableExpression) =
+    variableAccess globalTable variableExpression
 expression globalTable (AST.DivisionExpression lhs rhs)
     = expression globalTable lhs
     >> expression globalTable rhs
@@ -158,6 +158,8 @@ statement _ AST.EmptyStatement = pure ()
 statement globalTable (AST.CallStatement name arguments)
     = checkSymbol globalTable name
     >> traverse_ (expression globalTable) arguments
+statement globalTable (AST.CompoundStatement statements) =
+    traverse_ (statement globalTable) statements
 {- statement globalTable (AST.AssignmentStatement lvalue rvalue)
     = variableAccess globalTable lvalue
     >> expression globalTable rvalue
@@ -168,8 +170,6 @@ statement globalTable (AST.IfStatement ifCondition ifStatement elseStatement)
 statement globalTable (AST.WhileStatement whileCondition loop)
     = condition globalTable whileCondition
     >> statement globalTable loop
-statement globalTable (AST.CompoundStatement statements) =
-    traverse_ (statement globalTable) statements
 
 variableAccess :: SymbolTable -> AST.VariableAccess -> NameAnalysis ()
 variableAccess globalTable (AST.ArrayAccess arrayExpression indexExpression)
diff --git a/lib/Language/Elna/Frontend/Parser.hs b/lib/Language/Elna/Frontend/Parser.hs
index 4093f25..75f359e 100644
--- a/lib/Language/Elna/Frontend/Parser.hs
+++ b/lib/Language/Elna/Frontend/Parser.hs
@@ -34,27 +34,24 @@ import Text.Megaparsec
 import qualified Text.Megaparsec.Char.Lexer as Lexer
 import Text.Megaparsec.Char
     ( alphaNumChar
---    , char
+    , char
     , letterChar
     , space1
---    , string
+    , string
     )
 import Control.Applicative (Alternative(..))
 import Data.Maybe (isJust)
--- import Data.Functor (($>))
 
 type Parser = Parsec Void Text
 
 literalP :: Parser Literal
 literalP
-    = {- HexadecimalLiteral <$> (string "0x" *> lexeme Lexer.hexadecimal)
-    <|> -} IntegerLiteral <$> Lexer.signed space integerP
-    {- <|> CharacterLiteral <$> lexeme charP
-    <|> BooleanLiteral <$> (symbol "true" $> True)
-    <|> BooleanLiteral <$> (symbol "false" $> False)
+    = HexadecimalLiteral <$> (string "0x" *> lexeme Lexer.hexadecimal)
+    <|> IntegerLiteral <$> Lexer.signed space integerP
+    <|> CharacterLiteral <$> lexeme charP
   where
     charP = fromIntegral . fromEnum
-        <$> between (char '\'') (char '\'') Lexer.charLiteral -}
+        <$> between (char '\'') (char '\'') Lexer.charLiteral
 {-
 typeDefinitionP :: Parser Declaration
 typeDefinitionP = TypeDefinition
@@ -73,7 +70,7 @@ termP = choice
 operatorTable :: [[Operator Parser Expression]]
 operatorTable =
     [ unaryOperator
-    -- , factorOperator
+    , factorOperator
     , termOperator
     ]
   where
@@ -81,10 +78,10 @@ operatorTable =
         [ prefix "-" NegationExpression
         , prefix "+" id
         ]
-    {- factorOperator =
+    factorOperator =
         [ binary "*" ProductExpression
-        , binary "/" DivisionExpression
-        ] -}
+        -- , binary "/" DivisionExpression
+        ]
     termOperator =
         [ binary "+" SumExpression
         , binary "-" SubtractionExpression
diff --git a/lib/Language/Elna/Frontend/SymbolTable.hs b/lib/Language/Elna/Frontend/SymbolTable.hs
index 9ace33f..e90a942 100644
--- a/lib/Language/Elna/Frontend/SymbolTable.hs
+++ b/lib/Language/Elna/Frontend/SymbolTable.hs
@@ -40,9 +40,22 @@ scope parent (SymbolTable _ mappings) = SymbolTable (Just parent) mappings
 
 builtInSymbolTable :: SymbolTable
 builtInSymbolTable = SymbolTable Nothing $ HashMap.fromList
-    [ ("printi", ProcedureInfo empty Vector.empty)
+    [ ("printi", ProcedureInfo empty (Vector.singleton printiX))
+    , ("printc", ProcedureInfo empty (Vector.singleton printcI))
+    , ("exit", ProcedureInfo empty Vector.empty)
     , ("int", TypeInfo intType)
     ]
+  where
+    printiX = ParameterInfo
+        { name = "x"
+        , type' = intType
+        , isReferenceParameter = False
+        }
+    printcI = ParameterInfo
+        { name = "i"
+        , type' = intType
+        , isReferenceParameter = False
+        }
 
 toMap :: SymbolTable  -> HashMap Identifier Info
 toMap (SymbolTable _ map') = map'
diff --git a/lib/Language/Elna/Glue.hs b/lib/Language/Elna/Glue.hs
index 2313b2b..85c8401 100644
--- a/lib/Language/Elna/Glue.hs
+++ b/lib/Language/Elna/Glue.hs
@@ -70,6 +70,8 @@ statement localTable (AST.CallStatement (AST.Identifier callName) arguments) = d
         $ CallQuadruple callName
         $ fromIntegral
         $ Vector.length argumentStatements
+statement localTable (AST.CompoundStatement statements) =
+    fold <$> traverse (statement localTable) statements
 {- statement localTable (AST.AssignmentStatement variableAccess' assignee) = do
     (rhsOperand, rhsStatements) <- expression localTable assignee
     let variableType' = variableType variableAccess' localTable
@@ -105,9 +107,7 @@ statement localTable (AST.WhileStatement whileCondition whileStatement) = do
         <> conditionStatements
         <> Vector.fromList [jumpConstructor startLabel, GoToQuadruple endLabel, LabelQuadruple startLabel]
         <> whileStatements
-        <> Vector.fromList [GoToQuadruple conditionLabel, LabelQuadruple endLabel]
-statement localTable (AST.CompoundStatement statements) =
-    fold <$> traverse (statement localTable) statements -}
+        <> Vector.fromList [GoToQuadruple conditionLabel, LabelQuadruple endLabel] -}
 
 createTemporary :: Glue Variable
 createTemporary = do
@@ -233,6 +233,8 @@ expression localTable = \case
             ( VariableOperand tempVariable
             , Vector.snoc statements negationQuadruple
             )
+    (AST.ProductExpression lhs rhs) ->
+        binaryExpression ProductQuadruple lhs rhs
 {-    (AST.VariableExpression variableExpression) -> do
         let variableType' = variableType variableExpression localTable
         variableAccess' <- variableAccess localTable variableExpression Nothing variableType' mempty
@@ -246,8 +248,6 @@ expression localTable = \case
                     ( VariableOperand arrayAddress
                     , Vector.snoc statements arrayStatement
                     )
-    (AST.ProductExpression lhs rhs) ->
-        binaryExpression ProductQuadruple lhs rhs
     (AST.DivisionExpression lhs rhs) ->
         binaryExpression DivisionQuadruple lhs rhs -}
   where
@@ -263,8 +263,5 @@ expression localTable = \case
 
 literal :: AST.Literal -> Operand Variable
 literal (AST.IntegerLiteral integer) = IntOperand integer
-{-literal (AST.HexadecimalLiteral integer) = IntOperand integer
+literal (AST.HexadecimalLiteral integer) = IntOperand integer
 literal (AST.CharacterLiteral character) = IntOperand $ fromIntegral character
-literal (AST.BooleanLiteral boolean)
-    | boolean = IntOperand 1
-    | otherwise = IntOperand 0 -}
diff --git a/lib/Language/Elna/RiscV/CodeGenerator.hs b/lib/Language/Elna/RiscV/CodeGenerator.hs
index d20488c..439f99c 100644
--- a/lib/Language/Elna/RiscV/CodeGenerator.hs
+++ b/lib/Language/Elna/RiscV/CodeGenerator.hs
@@ -132,6 +132,32 @@ quadruple (NegationQuadruple operand1 (Store register))
             $ RiscV.BaseInstruction RiscV.Op
             $ RiscV.R register RiscV.SUB RiscV.Zero operandRegister1
             $ RiscV.Funct7 0b0100000
+quadruple (ProductQuadruple operand1 operand2 (Store register))
+    | IntOperand immediateOperand1 <- operand1
+    , IntOperand immediateOperand2 <- operand2 =
+        lui (immediateOperand1 * immediateOperand2) register
+    | VariableOperand variableOperand1 <- operand1
+    , VariableOperand variableOperand2 <- operand2 =
+        let Store operandRegister1 = variableOperand1
+            Store operandRegister2 = variableOperand2
+        in pure $ Instruction
+            $ RiscV.BaseInstruction RiscV.Op
+            $ RiscV.R register RiscV.MUL operandRegister1 operandRegister2 (RiscV.Funct7 0b0000001)
+    | VariableOperand variableOperand1 <- operand1
+    , IntOperand immediateOperand2 <- operand2 =
+        multiplyImmediateRegister variableOperand1 immediateOperand2
+    | IntOperand immediateOperand1 <- operand1
+    , VariableOperand variableOperand2 <- operand2 =
+        multiplyImmediateRegister variableOperand2 immediateOperand1
+  where
+    multiplyImmediateRegister variableOperand immediateOperand = 
+        let statements = lui immediateOperand register
+            Store operandRegister = variableOperand
+        in Vector.snoc statements
+            $ Instruction
+            $ RiscV.BaseInstruction RiscV.Op
+            $ RiscV.R register RiscV.MUL register operandRegister
+            $ RiscV.Funct7 0b0000001
 
 loadImmediateOrRegister :: RiscVOperand -> RiscV.XRegister -> (RiscV.XRegister, Vector Statement)
 loadImmediateOrRegister (IntOperand intValue) targetRegister =
diff --git a/tests/expectations/exit_between_statements.txt b/tests/expectations/exit_between_statements.txt
new file mode 100644
index 0000000..f2ad6c7
--- /dev/null
+++ b/tests/expectations/exit_between_statements.txt
@@ -0,0 +1 @@
+c
diff --git a/tests/expectations/print_2_statements.txt b/tests/expectations/print_2_statements.txt
new file mode 100644
index 0000000..783955e
--- /dev/null
+++ b/tests/expectations/print_2_statements.txt
@@ -0,0 +1,2 @@
+13
+2097150
diff --git a/tests/expectations/print_char.txt b/tests/expectations/print_char.txt
new file mode 100644
index 0000000..587be6b
--- /dev/null
+++ b/tests/expectations/print_char.txt
@@ -0,0 +1 @@
+x
diff --git a/tests/expectations/print_product.txt b/tests/expectations/print_product.txt
new file mode 100644
index 0000000..83b33d2
--- /dev/null
+++ b/tests/expectations/print_product.txt
@@ -0,0 +1 @@
+1000
diff --git a/tests/expectations/printi_hex.txt b/tests/expectations/printi_hex.txt
new file mode 100644
index 0000000..b0d7324
--- /dev/null
+++ b/tests/expectations/printi_hex.txt
@@ -0,0 +1 @@
+129
diff --git a/tests/vm/exit_between_statements.elna b/tests/vm/exit_between_statements.elna
new file mode 100644
index 0000000..9a79e86
--- /dev/null
+++ b/tests/vm/exit_between_statements.elna
@@ -0,0 +1,5 @@
+proc main() {
+  printc('c');
+  exit();
+  printi(1234);
+}
diff --git a/tests/vm/print_2_statements.elna b/tests/vm/print_2_statements.elna
new file mode 100644
index 0000000..e2b5970
--- /dev/null
+++ b/tests/vm/print_2_statements.elna
@@ -0,0 +1,4 @@
+proc main() {
+  printi(13);
+  printi(2097150);
+}
diff --git a/tests/vm/print_char.elna b/tests/vm/print_char.elna
new file mode 100644
index 0000000..c2c8fed
--- /dev/null
+++ b/tests/vm/print_char.elna
@@ -0,0 +1,3 @@
+proc main() {
+  printc('x');
+}
diff --git a/tests/vm/print_product.elna b/tests/vm/print_product.elna
new file mode 100644
index 0000000..b337428
--- /dev/null
+++ b/tests/vm/print_product.elna
@@ -0,0 +1,3 @@
+proc main() {
+  printi(20 * 50);
+}
diff --git a/tests/vm/printi_hex.elna b/tests/vm/printi_hex.elna
new file mode 100644
index 0000000..57ec6e3
--- /dev/null
+++ b/tests/vm/printi_hex.elna
@@ -0,0 +1,3 @@
+proc main() {
+  printi(0x81);
+}
diff --git a/tools/builtin.s b/tools/builtin.s
index ecea15b..0f5f82c 100644
--- a/tools/builtin.s
+++ b/tools/builtin.s
@@ -1,6 +1,12 @@
 .global printi
 .type printi, @function
 
+.global printc
+.type printc, @function
+
+.global exit
+.type exit, @function
+
 .global _start
 .type _start, @function
 
@@ -53,8 +59,35 @@ printi:
     addi sp, sp, 16
     ret
 
-_start:
-    call main
+printc:
+    addi sp, sp, -12
+    sw s0, 0(sp)
+    sw ra, 4(sp)
+    addi s0, sp, 12
+
+    addi t1, zero, '\n'
+    sb t1, -1(s0)
+
+    lw t0, 0(s0)
+    sb t0, -2(s0)
+
+    addi a0, zero, 1
+    addi a1, s0, -2
+    addi a2, zero, 2
+    addi a7, zero, 64
+    ecall
+
+    lw s0, 0(sp)
+    lw ra, 4(sp)
+    addi sp, sp, 12
+    ret
+
+exit:
     addi a0, zero, 0
     addi a7, zero, 93
     ecall
+    # ret
+
+_start:
+    call main
+    call exit