diff --git a/src/main/scala/millfork/CompilationOptions.scala b/src/main/scala/millfork/CompilationOptions.scala
index e850648a..e7e59c1f 100644
--- a/src/main/scala/millfork/CompilationOptions.scala
+++ b/src/main/scala/millfork/CompilationOptions.scala
@@ -174,6 +174,7 @@ case class CompilationOptions(platform: Platform,
           log.error("Either Sharp LR35902 or Intel 8080 opcodes have to be enabled")
         }
       case CpuFamily.I86 =>
+      case CpuFamily.M6809 =>
     }
   }
 
@@ -265,6 +266,7 @@ object CpuFamily extends Enumeration {
       case Mos | StrictMos | Ricoh | StrictRicoh | Cmos | HuC6280 | CE02 | Sixteen => M6502
       case Intel8080 | Intel8085 | StrictIntel8085 | Sharp | Z80 | StrictZ80 | EZ80 => I80
       case Intel8086 | Intel80186 => I86
+      case Cpu.Motorola6809 => M6809
     }
   }
 }
@@ -339,6 +341,10 @@ object Cpu extends Enumeration {
     * The Intel 80186 or 80188 processor
     */
   val Intel80186: Cpu.Value = Value
+  /**
+    * The Motorola 6809 processor
+    */
+  val Motorola6809: Cpu.Value = Value
 
   /**
     * Processors that can run code for WDC 65C02
@@ -367,6 +373,8 @@ object Cpu extends Enumeration {
 
   private val i80AlwaysDefaultFlags = alwaysDefaultFlags
 
+  private val m6809AlwaysDefaultFlags = alwaysDefaultFlags
+
   def defaultFlags(x: Cpu.Value): Set[CompilationFlag.Value] = x match {
     case StrictMos =>
       mosAlwaysDefaultFlags ++ Set(DecimalMode, PreventJmpIndirectBug)
@@ -396,6 +404,8 @@ object Cpu extends Enumeration {
       i80AlwaysDefaultFlags ++ Set(EmitExtended80Opcodes, EmitSharpOpcodes)
     case Intel8086 | Intel80186 =>
       i80AlwaysDefaultFlags ++ Set(EmitIntel8080Opcodes, UseIxForStack, EmitIntel8085Opcodes, EmitIllegals)
+    case Motorola6809 =>
+      m6809AlwaysDefaultFlags
   }
 
   def fromString(name: String)(implicit log: Logger): Cpu.Value = name match {
@@ -453,6 +463,8 @@ object Cpu extends Enumeration {
     case "intel80286" => Intel80186
     case "i80286" => Intel80186
     case "80286" => Intel80186
+      // disabled for now
+//    case "6809" => Motorola6809
     case _ => log.fatal("Unknown CPU achitecture: " + name)
   }
 
@@ -460,6 +472,7 @@ object Cpu extends Enumeration {
     CpuFamily.forType(cpu) match {
       case CpuFamily.M6502 => 2
       case CpuFamily.I80 | CpuFamily.I86 => 4
+      case CpuFamily.M6809 => 2
       case _ => ???
     }
 }
diff --git a/src/main/scala/millfork/assembly/m6809/MAddrMode.scala b/src/main/scala/millfork/assembly/m6809/MAddrMode.scala
new file mode 100644
index 00000000..b195a90d
--- /dev/null
+++ b/src/main/scala/millfork/assembly/m6809/MAddrMode.scala
@@ -0,0 +1,36 @@
+package millfork.assembly.m6809
+
+import millfork.node.M6809Register
+
+/**
+  * @author Karol Stasiak
+  */
+sealed trait MAddrMode
+
+case object Inherent extends MAddrMode
+
+case object InherentA extends MAddrMode
+
+case object InherentB extends MAddrMode
+
+case class TwoRegisters(source: M6809Register.Value, target: M6809Register.Value) extends MAddrMode
+
+case class RegisterSet(registers: Set[M6809Register.Value]) extends MAddrMode
+
+case class Absolute(indirect: Boolean) extends MAddrMode
+
+case class Indexed(base: M6809Register.Value, indirect: Boolean) extends MAddrMode
+
+case class AccumulatorIndexed(base: M6809Register.Value, indirect: Boolean) extends MAddrMode
+
+case class PostIncremented(base: M6809Register.Value, amount: Int, indirect: Boolean) extends MAddrMode
+
+case class PreDecremented(base: M6809Register.Value, amount: Int, indirect: Boolean) extends MAddrMode
+
+case object Relative extends MAddrMode
+
+case object Immediate extends MAddrMode
+
+case object NonExistent extends MAddrMode
+
+case object RawByte extends MAddrMode
diff --git a/src/main/scala/millfork/assembly/m6809/MLine.scala b/src/main/scala/millfork/assembly/m6809/MLine.scala
new file mode 100644
index 00000000..45b560a6
--- /dev/null
+++ b/src/main/scala/millfork/assembly/m6809/MLine.scala
@@ -0,0 +1,76 @@
+package millfork.assembly.m6809
+
+import millfork.assembly.{AbstractCode, Elidability, SourceLine}
+import millfork.env.{Constant, Label}
+import millfork.node.Position
+
+/**
+  * @author Karol Stasiak
+  */
+
+object MLine0 {
+
+  @inline
+  def unapply(a: MLine): Some[(MOpcode.Value, MAddrMode, Constant)] = Some(a.opcode, a.addrMode, a.parameter)
+}
+
+object MLine {
+
+  import MOpcode._
+
+  def label(label: String): MLine = MLine.label(Label(label))
+
+  def label(label: Label): MLine = MLine(LABEL, NonExistent, label.toAddress)
+
+  def inherent(opcode: MOpcode.Value): MLine = MLine(opcode, Inherent, Constant.Zero)
+
+  def inherentA(opcode: MOpcode.Value): MLine = MLine(opcode, InherentA, Constant.Zero)
+
+  def inherentB(opcode: MOpcode.Value): MLine = MLine(opcode, InherentB, Constant.Zero)
+}
+
+case class MLine(opcode: MOpcode.Value, addrMode: MAddrMode, parameter: Constant, elidability: Elidability.Value = Elidability.Elidable, source: Option[SourceLine] = None) extends AbstractCode {
+
+  def pos(s: Option[SourceLine]): MLine = if (s.isEmpty || s == source) this else this.copy(source = s)
+
+  def pos(s1: Option[SourceLine], s2: Option[SourceLine]): MLine = pos(Seq(s1, s2))
+
+  def position(s: Option[Position]): MLine = pos(SourceLine.of(s))
+
+  def positionIfEmpty(s: Option[Position]): MLine = if (s.isEmpty || source.isDefined) this else pos(SourceLine.of(s))
+
+  def pos(s: Seq[Option[SourceLine]]): MLine = pos(SourceLine.merge(s))
+
+  def mergePos(s: Seq[Option[SourceLine]]): MLine = if (s.isEmpty) this else pos(SourceLine.merge(this.source, s))
+
+  def refersTo(name: String): Boolean = parameter.refersTo(name)
+
+  override def sizeInBytes: Int = 1 // TODO
+
+  override def isPrintable: Boolean = true // TODO
+
+  override def toString: String = {
+    if (opcode == MOpcode.LABEL) return parameter + ":"
+    if (opcode == MOpcode.BYTE) return s"    FCB $parameter"
+    val suffix = addrMode match {
+      case NonExistent => ""
+      case Inherent => ""
+      case InherentA => "A"
+      case InherentB => "B"
+      case Relative => s" $parameter"
+      case Absolute(false) => s" $parameter"
+      case Indexed(base, false) => s" $parameter,$base"
+      case Indexed(base, true) => s" [$parameter,$base]"
+      case PreDecremented(base, 1, false) => s" ,-$base"
+      case PreDecremented(base, 2, false) => s" ,--$base"
+      case PreDecremented(base, 1, true) => s" [-$base]"
+      case PreDecremented(base, 2, true) => s" [--$base]"
+      case PostIncremented(base, 1, false) => s" ,$base+"
+      case PostIncremented(base, 2, false) => s" ,$base++"
+      case PostIncremented(base, 1, true) => s" [,$base+]"
+      case PostIncremented(base, 2, true) => s" [,$base++]"
+    }
+    s"    $opcode$suffix"
+  }
+}
+
diff --git a/src/main/scala/millfork/assembly/m6809/MOpcode.scala b/src/main/scala/millfork/assembly/m6809/MOpcode.scala
new file mode 100644
index 00000000..324f5e19
--- /dev/null
+++ b/src/main/scala/millfork/assembly/m6809/MOpcode.scala
@@ -0,0 +1,35 @@
+package millfork.assembly.m6809
+
+/**
+  * @author Karol Stasiak
+  */
+
+object MFlag extends Enumeration {
+  val Z, C, H, N, V = Value
+}
+
+object MOpcode extends Enumeration {
+  val ABX, ADCA, ADCB, ADDA, ADDB, ADDD, ANDA, ANDB, ANDCC, ASL, ASR,
+  BITA, BITB,
+  BRA, BRN, BHI, BLS, BCC, BCS, BNE, BEQ, BVC, BVS, BPL, BMI, BGE, BLT, BGT, BLE,
+  CLR, CMPA, CMPB, CMPD, CMPS, CMPU, CMPX, CMPY, COMA, COMB, COM, CWAI,
+  DAA, DEC,
+  EORA, EORB, EXG,
+  INC,
+  JMP, JSR,
+  LDA, LDB, LDD, LDS, LDU, LDX, LDY, LEAS, LEAU, LEAX, LEAY, LSR,
+  LBRA, LBRN, LBHI, LBLS, LBCC, LBCS, LBNE, LBEQ, LBVC, LBVS, LBPL, LBMI, LBGE, LBLT, LBGT, LBLE,
+  MUL,
+  NEG, NOP,
+  ORA, ORB, ORCC,
+  PSHS, PSHU, PULS, PULU,
+  ROL, ROR, RTI, RTS,
+  SBCA, SBCB, SEX, STA, STB, STD, STS, STU, STX, STY, SUBA, SUBB, SUBD, SWI, SWI2, SWI3, SYNC,
+  TFR, TST,
+  DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC, CHANGED_MEM, BYTE, LABEL = Value
+
+  val NoopDiscard: Set[MOpcode.Value] = Set(DISCARD_D, DISCARD_X, DISCARD_Y, DISCARD_CC)
+  val PrefixedBy10: Set[MOpcode.Value] = Set(CMPD, CMPY, LDS, LDY, SWI2) // TODO: branches
+  val PrefixedBy11: Set[MOpcode.Value] = Set(CMPS, CMPU, SWI3)
+  val Prefixed: Set[MOpcode.Value] = PrefixedBy10 ++ PrefixedBy11
+}
diff --git a/src/main/scala/millfork/compiler/m6809/M6809Compiler.scala b/src/main/scala/millfork/compiler/m6809/M6809Compiler.scala
new file mode 100644
index 00000000..bc1c77b1
--- /dev/null
+++ b/src/main/scala/millfork/compiler/m6809/M6809Compiler.scala
@@ -0,0 +1,19 @@
+package millfork.compiler.m6809
+
+import millfork.assembly.Elidability
+import millfork.assembly.m6809.{Inherent, MLine, MOpcode, NonExistent}
+import millfork.compiler.{AbstractCompiler, CompilationContext}
+import millfork.env.{Constant, Label, MemoryAddressConstant}
+
+/**
+  * @author Karol Stasiak
+  */
+object M6809Compiler extends AbstractCompiler[MLine] {
+  override def compile(ctx: CompilationContext): List[MLine] = {
+    ctx.env.nameCheck(ctx.function.code)
+    val label = MLine.label(Label(ctx.function.name)).copy(elidability = Elidability.Fixed)
+    val chunk = packHalves(M6809StatementCompiler.compile(ctx, new M6809StatementPreprocessor(ctx, ctx.function.code)()))
+    // TODO
+    label :: chunk
+  }
+}
diff --git a/src/main/scala/millfork/compiler/m6809/M6809StatementCompiler.scala b/src/main/scala/millfork/compiler/m6809/M6809StatementCompiler.scala
new file mode 100644
index 00000000..eff6dbf7
--- /dev/null
+++ b/src/main/scala/millfork/compiler/m6809/M6809StatementCompiler.scala
@@ -0,0 +1,50 @@
+package millfork.compiler.m6809
+
+import millfork.assembly.BranchingOpcodeMapping
+import millfork.assembly.m6809.MLine
+import millfork.compiler.{AbstractCompiler, AbstractStatementCompiler, BranchSpec, CompilationContext}
+import millfork.node.{ExecutableStatement, Expression, M6809AssemblyStatement, ReturnStatement, VariableExpression, WhileStatement}
+import millfork.assembly.m6809.MOpcode._
+import millfork.env.{Label, ThingInMemory}
+/**
+  * @author Karol Stasiak
+  */
+object M6809StatementCompiler extends AbstractStatementCompiler[MLine] {
+  def compile(ctx: CompilationContext, statement: ExecutableStatement): (List[MLine], List[MLine]) = {
+    val code: (List[MLine], List[MLine]) = statement match {
+      case ReturnStatement(None) =>
+        // TODO: clean stack
+        // TODO: RTI
+        List(MLine.inherent(RTS)) -> Nil
+      case M6809AssemblyStatement(opcode, addrMode, expression, elidability) =>
+        ctx.env.evalForAsm(expression) match {
+          case Some(e) => List(MLine(opcode, addrMode, e, elidability)) -> Nil
+          case None =>
+            println(statement)
+            ???
+        }
+      case WhileStatement(VariableExpression("true"),List(),List(),_) =>
+        Nil -> Nil // TODO
+      case _ =>
+        println(statement)
+        ???
+    }
+    code._1.map(_.positionIfEmpty(statement.position)) -> code._2.map(_.positionIfEmpty(statement.position))
+  }
+
+  override def labelChunk(labelName: String): List[MLine] = ???
+
+  override def jmpChunk(label: Label): List[MLine] = ???
+
+  override def branchChunk(opcode: BranchingOpcodeMapping, labelName: String): List[MLine] = ???
+
+  override def compileExpressionForBranching(ctx: CompilationContext, expr: Expression, branching: BranchSpec): List[MLine] = ???
+
+  override def replaceLabel(ctx: CompilationContext, line: MLine, from: String, to: String): MLine = ???
+
+  override def returnAssemblyStatement: ExecutableStatement = ???
+
+  override def callChunk(label: ThingInMemory): List[MLine] = ???
+
+  override def areBlocksLarge(blocks: List[MLine]*): Boolean = ???
+}
diff --git a/src/main/scala/millfork/compiler/m6809/M6809StatementPreprocessor.scala b/src/main/scala/millfork/compiler/m6809/M6809StatementPreprocessor.scala
new file mode 100644
index 00000000..a452352f
--- /dev/null
+++ b/src/main/scala/millfork/compiler/m6809/M6809StatementPreprocessor.scala
@@ -0,0 +1,13 @@
+package millfork.compiler.m6809
+
+import millfork.assembly.m6809.MLine
+import millfork.compiler.{AbstractStatementPreprocessor, CompilationContext}
+import millfork.node.{ExecutableStatement, ForStatement}
+
+/**
+  * @author Karol Stasiak
+  */
+class M6809StatementPreprocessor(ctx: CompilationContext, statements: List[ExecutableStatement])
+  extends AbstractStatementPreprocessor(ctx, statements) {
+  override def maybeOptimizeForStatement(f: ForStatement): Option[(ExecutableStatement, VV)] = None
+}
diff --git a/src/main/scala/millfork/env/Environment.scala b/src/main/scala/millfork/env/Environment.scala
index 8d6db814..4d174143 100644
--- a/src/main/scala/millfork/env/Environment.scala
+++ b/src/main/scala/millfork/env/Environment.scala
@@ -1,5 +1,6 @@
 package millfork.env
 
+import millfork.assembly.m6809.{MOpcode, NonExistent}
 import millfork.assembly.{BranchingOpcodeMapping, Elidability}
 import millfork.{env, _}
 import millfork.assembly.mos.{AddrMode, Opcode}
@@ -1806,6 +1807,7 @@ class Environment(val parent: Option[Environment], val prefix: String, val cpuFa
         case CpuFamily.M6502 => List(MosAssemblyStatement(Opcode.CHANGED_MEM, AddrMode.DoesNotExist, LiteralExpression(0, 1), Elidability.Fixed))
         case CpuFamily.I80 => List(Z80AssemblyStatement(ZOpcode.CHANGED_MEM, NoRegisters, None, LiteralExpression(0, 1), Elidability.Fixed))
         case CpuFamily.I86 => List(Z80AssemblyStatement(ZOpcode.CHANGED_MEM, NoRegisters, None, LiteralExpression(0, 1), Elidability.Fixed))
+        case CpuFamily.M6809 => List(M6809AssemblyStatement(MOpcode.CHANGED_MEM, NonExistent, LiteralExpression(0, 1), Elidability.Fixed))
         case _ => ???
       })
     }
diff --git a/src/main/scala/millfork/node/Node.scala b/src/main/scala/millfork/node/Node.scala
index 7f49648a..5ef4f141 100644
--- a/src/main/scala/millfork/node/Node.scala
+++ b/src/main/scala/millfork/node/Node.scala
@@ -1,6 +1,7 @@
 package millfork.node
 
 import millfork.assembly.Elidability
+import millfork.assembly.m6809.{MAddrMode, MOpcode}
 import millfork.assembly.mos.{AddrMode, Opcode}
 import millfork.assembly.z80.{ZOpcode, ZRegisters}
 import millfork.env.{Constant, ParamPassingConvention, Type}
@@ -197,6 +198,15 @@ object ZRegister extends Enumeration {
   val main7Registers: Set[ZRegister.Value] = Set[ZRegister.Value](ZRegister.A, ZRegister.B, ZRegister.C, ZRegister.D, ZRegister.D, ZRegister.E, ZRegister.H, ZRegister.L)
 }
 
+object M6809Register extends Enumeration {
+  val A, B, D, DP, X, Y, U, S, PC, CC = Value
+
+  def registerSize(reg: Value): Int = reg match {
+    case D | X | Y | U | S | PC => 2
+    case A | B | DP | CC => 1
+  }
+}
+
 //case class Indexing(child: Expression, register: Register.Value) extends Expression
 
 case class VariableExpression(name: String) extends LhsExpression {
@@ -501,6 +511,10 @@ case class Z80AssemblyStatement(opcode: ZOpcode.Value, registers: ZRegisters, of
   override def getAllExpressions: List[Expression] = List(expression)
 }
 
+case class M6809AssemblyStatement(opcode: MOpcode.Value, addrMode: MAddrMode, expression: Expression, elidability: Elidability.Value) extends ExecutableStatement {
+  override def getAllExpressions: List[Expression] = List(expression)
+}
+
 case class IfStatement(condition: Expression, thenBranch: List[ExecutableStatement], elseBranch: List[ExecutableStatement]) extends CompoundStatement {
   override def getAllExpressions: List[Expression] = condition :: (thenBranch ++ elseBranch).flatMap(_.getAllExpressions)
 
diff --git a/src/main/scala/millfork/output/M6809Assembler.scala b/src/main/scala/millfork/output/M6809Assembler.scala
new file mode 100644
index 00000000..b7149d02
--- /dev/null
+++ b/src/main/scala/millfork/output/M6809Assembler.scala
@@ -0,0 +1,103 @@
+package millfork.output
+
+import millfork.{CompilationOptions, Platform}
+import millfork.assembly.m6809.{MOpcode, _}
+import millfork.compiler.m6809.M6809Compiler
+import millfork.env.{Environment, Label, MemoryAddressConstant, NormalFunction}
+import millfork.node.{NiceFunctionProperty, Program}
+
+import scala.collection.mutable
+
+/**
+  * @author Karol Stasiak
+  */
+class M6809Assembler(program: Program,
+                     rootEnv: Environment,
+                     platform: Platform) extends AbstractAssembler[MLine](program, rootEnv, platform, M6809InliningCalculator, M6809Compiler) {
+  override def bytePseudoopcode: String = "FCB"
+
+  override def deduplicate(options: CompilationOptions, compiledFunctions: mutable.Map[String, CompiledFunction[MLine]]): Unit = ()
+
+  override def injectLabels(labelMap: Map[String, (Int, Int)], code: List[MLine]): List[MLine] = code
+
+  override def quickSimplify(code: List[MLine]): List[MLine] = code
+
+  override def gatherNiceFunctionProperties(niceFunctionProperties: mutable.Set[(NiceFunctionProperty, String)], functionName: String, code: List[MLine]): Unit = ()
+
+  override def performFinalOptimizationPass(f: NormalFunction, actuallyOptimize: Boolean, options: CompilationOptions, code: List[MLine]): List[MLine] = code
+
+  override def emitInstruction(bank: String, options: CompilationOptions, index: Int, instr: MLine): Int = {
+    import millfork.assembly.m6809.MOpcode._
+    instr match {
+      case MLine0(BYTE, RawByte, c) =>
+        writeByte(bank, index, c)
+        index + 1
+      case MLine0(BYTE, _, _) => log.fatal("BYTE opcode failure")
+      case MLine0(_, RawByte, _) => log.fatal("BYTE opcode failure")
+      case MLine0(LABEL, NonExistent, MemoryAddressConstant(Label(labelName))) =>
+        val bank0 = mem.banks(bank)
+        labelMap(labelName) = bank0.index -> index
+        index
+      case MLine0(op, NonExistent, _) if MOpcode.NoopDiscard(op) =>
+        index
+      case MLine0(op, Inherent, _) if M6809Assembler.inherent.contains(op) =>
+        writeByte(bank, index, M6809Assembler.inherent(op))
+        index + 1
+      case MLine0(op, InherentA, _) if M6809Assembler.inherentA.contains(op) =>
+        writeByte(bank, index, M6809Assembler.inherentA(op))
+        index + 1
+      case MLine0(op, InherentB, _) if M6809Assembler.inherentB.contains(op) =>
+        writeByte(bank, index, M6809Assembler.inherentB(op))
+        index + 1
+      case MLine0(op, Immediate, param) if M6809Assembler.immediate.contains(op) =>
+        writeByte(bank, index, M6809Assembler.immediate(op))
+        writeByte(bank, index + 1, param)
+        index + 1
+      case _ =>
+        // TODO
+        throw new IllegalArgumentException("Not supported: " + instr)
+    }
+  }
+}
+
+object M6809Assembler {
+
+  val inherent: mutable.Map[MOpcode.Value, Byte] = mutable.Map[MOpcode.Value, Byte]()
+  val inherentA: mutable.Map[MOpcode.Value, Byte] = mutable.Map[MOpcode.Value, Byte]()
+  val inherentB: mutable.Map[MOpcode.Value, Byte] = mutable.Map[MOpcode.Value, Byte]()
+  val immediate: mutable.Map[MOpcode.Value, Byte] = mutable.Map[MOpcode.Value, Byte]()
+
+  private def inh(op: MOpcode.Value, value: Int): Unit = inherent(op) = value.toByte
+
+  private def inab(op: MOpcode.Value, value: Int): Unit = {
+    inherentA(op) = value.toByte
+    inherentB(op) = value.+(0x10).toByte
+  }
+
+  private def imm(op: MOpcode.Value, value: Int): Unit = immediate(op) = value.toByte
+
+  import MOpcode._
+
+  inh(ABX, 0x3a)
+  inh(DAA, 0x19)
+  inh(MUL, 0x3d)
+  inh(NOP, 0x12)
+  inh(RTI, 0x3B)
+  inh(RTS, 0x39)
+  inh(SEX, 0x1d)
+  inh(SWI, 0x3f)
+  inh(SYNC, 0x13)
+
+  inab(ASL, 0x48)
+  inab(ASR, 0x47)
+  inab(CLR, 0x4f)
+  inab(COM, 0x43)
+  inab(DEC, 0x4a)
+  inab(INC, 0x48)
+  inab(LSR, 0x44)
+  inab(NEG, 0x40)
+  inab(ROL, 0x49)
+  inab(ROR, 0x46)
+  inab(TST, 0x4d)
+
+}
\ No newline at end of file
diff --git a/src/main/scala/millfork/output/M6809InliningCalculator.scala b/src/main/scala/millfork/output/M6809InliningCalculator.scala
new file mode 100644
index 00000000..9c382bde
--- /dev/null
+++ b/src/main/scala/millfork/output/M6809InliningCalculator.scala
@@ -0,0 +1,16 @@
+package millfork.output
+
+import millfork.JobContext
+import millfork.assembly.m6809.MLine
+
+/**
+  * @author Karol Stasiak
+  */
+object M6809InliningCalculator extends AbstractInliningCalculator[MLine] {
+  override def codeForInlining(fname: String, functionsThatCanBeCalledFromInlinedFunctions: Set[String], code: List[MLine]): Option[List[MLine]] = None
+
+  override def inline(code: List[MLine], inlinedFunctions: Map[String, List[MLine]], jobContext: JobContext): List[MLine] = {
+    if (inlinedFunctions.isEmpty) code
+    else ???
+  }
+}
diff --git a/src/main/scala/millfork/parser/M6809Parser.scala b/src/main/scala/millfork/parser/M6809Parser.scala
new file mode 100644
index 00000000..2f087d47
--- /dev/null
+++ b/src/main/scala/millfork/parser/M6809Parser.scala
@@ -0,0 +1,31 @@
+package millfork.parser
+
+import fastparse.all
+import millfork.CompilationOptions
+import millfork.assembly.m6809.MLine
+import millfork.node.{ExecutableStatement, ParameterDeclaration, Position, Statement}
+import millfork.output.{MemoryAlignment, NoAlignment, WithinPageAlignment}
+
+/**
+  * @author Karol Stasiak
+  */
+class M6809Parser(filename: String,
+                     input: String,
+                     currentDirectory: String,
+                     options: CompilationOptions,
+                     featureConstants: Map[String, Long],
+                     useIntelSyntax: Boolean) extends MfParser[MLine](filename, input, currentDirectory, options, featureConstants) {
+  override def allowIntelHexAtomsInAssembly: Boolean = false
+
+  override def asmParamDefinition: all.P[ParameterDeclaration] = ???
+
+  def fastAlignmentForArrays: MemoryAlignment = WithinPageAlignment
+
+  def fastAlignmentForFunctions: MemoryAlignment = NoAlignment
+
+  override def asmStatement: all.P[ExecutableStatement] = ???
+
+  override def validateAsmFunctionBody(p: Position, flags: Set[String], name: String, statements: Option[List[Statement]]): Unit = {
+    // TODO
+  }
+}
diff --git a/src/test/scala/millfork/test/BasicSymonTest.scala b/src/test/scala/millfork/test/BasicSymonTest.scala
index 55ee7a88..8c181506 100644
--- a/src/test/scala/millfork/test/BasicSymonTest.scala
+++ b/src/test/scala/millfork/test/BasicSymonTest.scala
@@ -9,7 +9,7 @@ import org.scalatest.{FunSuite, Matchers}
   */
 class BasicSymonTest extends FunSuite with Matchers {
   test("Empty test") {
-    EmuUnoptimizedCrossPlatformRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp, Cpu.Intel8086)(
+    EmuUnoptimizedCrossPlatformRun(Cpu.Mos, Cpu.Z80, Cpu.Intel8080, Cpu.Sharp, Cpu.Intel8086, Cpu.Motorola6809)(
       """
         | void main () {
         |
diff --git a/src/test/scala/millfork/test/emu/EmuM6809Run.scala b/src/test/scala/millfork/test/emu/EmuM6809Run.scala
new file mode 100644
index 00000000..b7a97f9f
--- /dev/null
+++ b/src/test/scala/millfork/test/emu/EmuM6809Run.scala
@@ -0,0 +1,175 @@
+package millfork.test.emu
+
+import java.nio.charset.StandardCharsets
+import java.nio.file.{Files, Paths}
+
+import fastparse.core.Parsed.{Failure, Success}
+import millfork._
+import millfork.assembly.AssemblyOptimization
+import millfork.assembly.m6809.MLine
+import millfork.compiler.m6809.M6809Compiler
+import millfork.compiler.{CompilationContext, LabelGenerator}
+import millfork.env.{Environment, InitializedArray, InitializedMemoryVariable, NormalFunction}
+import millfork.node.opt.NodeOptimization
+import millfork.node.{Program, StandardCallGraph}
+import millfork.output.{M6809Assembler, MemoryBank}
+import millfork.parser.{PreprocessingResult, Preprocessor, Z80Parser}
+import org.scalatest.Matchers
+
+import scala.collection.JavaConverters._
+import scala.collection.mutable
+
+/**
+  * @author Karol Stasiak
+  */
+object EmuM6809Run {
+
+  private def preload(cpu: millfork.Cpu.Value, filename: String):  Option[Program] = {
+    TestErrorReporting.log.info(s"Loading $filename for $cpu")
+    val source = Files.readAllLines(Paths.get(filename), StandardCharsets.US_ASCII).asScala.mkString("\n")
+    val options = CompilationOptions(EmuPlatform.get(cpu), Map(
+          CompilationFlag.LenientTextEncoding -> true
+        ), None, 0, Map(), JobContext(TestErrorReporting.log, new LabelGenerator))
+    val PreprocessingResult(preprocessedSource, features, _) = Preprocessor.preprocessForTest(options, source)
+    TestErrorReporting.log.debug(s"Features: $features")
+    TestErrorReporting.log.info(s"Parsing $filename")
+    val parser = Z80Parser(filename, preprocessedSource, "", options, features, useIntelSyntax = false)
+    parser.toAst match {
+      case Success(x, _) => Some(x)
+      case f: Failure[_, _] =>
+        TestErrorReporting.log.error(f.toString)
+        TestErrorReporting.log.error(f.extra.toString)
+        TestErrorReporting.log.error(f.lastParser.toString)
+        TestErrorReporting.log.error("Syntax error", Some(parser.lastPosition))
+        TestErrorReporting.log.error("Parsing error")
+        ???
+    }
+  }
+
+  private lazy val cache: mutable.Map[(millfork.Cpu.Value, String), Option[Program]] = mutable.Map[(millfork.Cpu.Value, String), Option[Program]]()
+  private def get(cpu: millfork.Cpu.Value, path: String): Program =
+    synchronized { cache.getOrElseUpdate(cpu->path, preload(cpu, path)).getOrElse(throw new IllegalStateException()) }
+
+  def cachedMath(cpu: millfork.Cpu.Value): Program = get(cpu, "include/m6809_math.mfk")
+  def cachedStdio(cpu: millfork.Cpu.Value): Program = get(cpu, "src/test/resources/include/dummy_stdio.mfk")
+}
+
+class EmuM6809Run(cpu: millfork.Cpu.Value, nodeOptimizations: List[NodeOptimization], assemblyOptimizations: List[AssemblyOptimization[MLine]]) extends Matchers {
+  def inline: Boolean = false
+
+  def optimizeForSize: Boolean = false
+
+  private val TooManyCycles: Long = 1500000
+
+  def apply(source: String): MemoryBank = {
+    apply2(source)._2
+  }
+
+  def apply2(source: String): (Timings, MemoryBank) = {
+    Console.out.flush()
+    Console.err.flush()
+    val log = TestErrorReporting.log
+    println(source)
+    val platform = EmuPlatform.get(cpu)
+    val extraFlags = Map(
+      CompilationFlag.DangerousOptimizations -> true,
+      CompilationFlag.EnableInternalTestSyntax -> true,
+      CompilationFlag.InlineFunctions -> this.inline,
+      CompilationFlag.OptimizeStdlib -> this.inline,
+      CompilationFlag.OptimizeForSize -> this.optimizeForSize,
+      CompilationFlag.SubroutineExtraction -> optimizeForSize,
+      CompilationFlag.EmitIllegals -> false,
+      CompilationFlag.LenientTextEncoding -> true)
+    val options = CompilationOptions(platform, millfork.Cpu.defaultFlags(cpu).map(_ -> true).toMap ++ extraFlags, None, 0, Map(), JobContext(log, new LabelGenerator))
+    println(cpu)
+    println(options.flags.filter(_._2).keys.toSeq.sorted)
+    log.hasErrors = false
+    log.verbosity = 999
+    var effectiveSource = source
+    if (!source.contains("_panic")) effectiveSource += "\n void _panic(){while(true){}}"
+    log.setSource(Some(effectiveSource.linesIterator.toIndexedSeq))
+    val PreprocessingResult(preprocessedSource, features, pragmas) = Preprocessor.preprocessForTest(options, effectiveSource)
+    // tests use Intel syntax only when forced to:
+    val parserF = Z80Parser("", preprocessedSource, "", options, features, pragmas.contains("intel_syntax"))
+    parserF.toAst match {
+      case Success(unoptimized, _) =>
+        log.assertNoErrors("Parse failed")
+
+
+        // prepare
+        val withLibraries = {
+          var tmp = unoptimized
+//          tmp += EmuM6809Run.cachedMath(cpu) // TODO: add this only after you implement maths
+          if (source.contains("import stdio")) {
+            tmp += EmuM6809Run.cachedStdio(cpu)
+          }
+          tmp
+        }
+        val program = nodeOptimizations.foldLeft(withLibraries.applyImportantAliases)((p, opt) => p.applyNodeOptimization(opt, options))
+        val callGraph = new StandardCallGraph(program, log)
+        val env = new Environment(None, "", CpuFamily.I80, options)
+        env.collectDeclarations(program, options)
+
+        val hasOptimizations = assemblyOptimizations.nonEmpty
+        var unoptimizedSize = 0L
+        // print unoptimized asm
+        env.allPreallocatables.foreach {
+          case f: NormalFunction =>
+            val unoptimized = M6809Compiler.compile(CompilationContext(f.environment, f, 0, options, Set()))
+            unoptimizedSize += unoptimized.map(_.sizeInBytes).sum
+          case d: InitializedArray =>
+            unoptimizedSize += d.contents.length
+          case d: InitializedMemoryVariable =>
+            unoptimizedSize += d.typ.size
+        }
+
+        log.assertNoErrors("Compile failed")
+
+
+        // compile
+        val env2 = new Environment(None, "", CpuFamily.I80, options)
+        env2.collectDeclarations(program, options)
+        val assembler = new M6809Assembler(program, env2, platform)
+        val output = assembler.assemble(callGraph, assemblyOptimizations, options)
+        println(";;; compiled: -----------------")
+        output.asm.takeWhile(s => !(s.startsWith(".") && s.contains("= $"))).filterNot(_.contains("////; DISCARD_")).foreach(println)
+        println(";;; ---------------------------")
+        assembler.labelMap.foreach { case (l, (_, addr)) => println(f"$l%-15s $$$addr%04x") }
+
+        val optimizedSize = assembler.mem.banks("default").initialized.count(identity).toLong
+        if (unoptimizedSize == optimizedSize) {
+          println(f"Size:             $unoptimizedSize%5d B")
+        } else {
+          println(f"Unoptimized size: $unoptimizedSize%5d B")
+          println(f"Optimized size:   $optimizedSize%5d B")
+          println(f"Gain:              ${(100L * (unoptimizedSize - optimizedSize) / unoptimizedSize.toDouble).round}%5d%%")
+        }
+
+        if (log.hasErrors) {
+          fail("Code generation failed")
+        }
+
+        val memoryBank = assembler.mem.banks("default")
+        (0x1f0 until 0x200).foreach(i => memoryBank.readable(i) = true)
+        (0xff00 to 0xffff).foreach{i =>
+          memoryBank.readable(i) = true
+          memoryBank.writeable(i) = true
+        }
+
+        (0x200 until 0x2000).takeWhile(memoryBank.occupied(_)).map(memoryBank.output).grouped(16).map(_.map(i => f"$i%02x").mkString(" ")).foreach(log.debug(_))
+        val timings = platform.cpu match {
+          case _ =>
+            Timings(-1, -1) -> memoryBank
+        }
+        log.clearErrors()
+        timings
+      case f: Failure[_, _] =>
+        println(f)
+        println(f.extra.toString)
+        println(f.lastParser.toString)
+        log.error("Syntax error", Some(parserF.lastPosition))
+        fail("Parsing error")
+    }
+  }
+
+}
diff --git a/src/test/scala/millfork/test/emu/EmuUnoptimizedCrossPlatformRun.scala b/src/test/scala/millfork/test/emu/EmuUnoptimizedCrossPlatformRun.scala
index 7038b68e..4c6bd4b7 100644
--- a/src/test/scala/millfork/test/emu/EmuUnoptimizedCrossPlatformRun.scala
+++ b/src/test/scala/millfork/test/emu/EmuUnoptimizedCrossPlatformRun.scala
@@ -14,6 +14,7 @@ object EmuUnoptimizedCrossPlatformRun {
     val (_, mz) = if (platforms.contains(Cpu.Z80)) EmuUnoptimizedZ80Run.apply2(source) else Timings(-1, -1) -> null
     val (_, mi) = if (platforms.contains(Cpu.Intel8080)) EmuUnoptimizedIntel8080Run.apply2(source) else Timings(-1, -1) -> null
     val (_, ms) = if (platforms.contains(Cpu.Sharp)) EmuUnoptimizedSharpRun.apply2(source) else Timings(-1, -1) -> null
+    val (_, mo) = if (platforms.contains(Cpu.Motorola6809)) EmuUnoptimizedM6809Run.apply2(source) else Timings(-1, -1) -> null
     val (_, mx) = if (Settings.enableIntel8086Tests && platforms.contains(Cpu.Intel8086)) EmuUnoptimizedIntel8086Run.apply2(source) else Timings(-1, -1) -> null
     if (Settings.enable6502Tests && platforms.contains(Cpu.Mos)) {
       println(f"Running 6502")
@@ -43,5 +44,9 @@ object EmuUnoptimizedCrossPlatformRun {
       println(f"Running 8086")
       verifier(mx)
     }
+    if (Settings.enableMotorola6809Tests && platforms.contains(Cpu.Motorola6809)) {
+      println(f"Running 6809")
+      verifier(mx)
+    }
   }
 }
diff --git a/src/test/scala/millfork/test/emu/EmuUnoptimizedRun.scala b/src/test/scala/millfork/test/emu/EmuUnoptimizedRun.scala
index 079ea243..6e16c62f 100644
--- a/src/test/scala/millfork/test/emu/EmuUnoptimizedRun.scala
+++ b/src/test/scala/millfork/test/emu/EmuUnoptimizedRun.scala
@@ -25,3 +25,5 @@ object EmuUnoptimizedIntel8085Run extends EmuZ80Run(Cpu.Intel8085, Nil, Nil)
 object EmuUnoptimizedIntel8086Run extends EmuI86Run(Nil, Nil)
 
 object EmuUnoptimizedSharpRun extends EmuZ80Run(Cpu.Sharp, Nil, Nil)
+
+object EmuUnoptimizedM6809Run extends EmuM6809Run(Cpu.Motorola6809, Nil, Nil)
diff --git a/src/test/scala/millfork/test/emu/Settings.scala b/src/test/scala/millfork/test/emu/Settings.scala
index 8b822afa..d5c923c1 100644
--- a/src/test/scala/millfork/test/emu/Settings.scala
+++ b/src/test/scala/millfork/test/emu/Settings.scala
@@ -48,6 +48,12 @@ object Settings {
     */
   val enableUnemulatedTests: Boolean = true
 
+  /**
+    * Should the Motorola 6809 tests be enabled?
+    * Motorola 6809 emulation is not yet implemented, so keep this false for the time being.
+    */
+  val enableMotorola6809Tests: Boolean = false
+
   // the following are the core platforms and they are all tested by default
 
   val enable6502Tests: Boolean = true