Implemented most of flipper in KickC

src/dk/camelot64/kickc/TODO.txt

@@ -0,0 +1,40 @@
+Features
+- Move the main code into a main() function, and disallow code outside functions. The main function per default has no parameters and exits with RTS.
+- Implement Register Allocation (that utilize real registers - and non-zeropage memory)
+- Add Fixed Point number types
+- Create a proper main function for the compiler
+- Add for loop
+- Add imports
+- Add structs
+- Add preprocessing / find a way to allow some functions to run at compile time
+- Implement inline compilation of functions (and a mechanism for choosing which methods / calls to inline)
+- Add ability to call ASM code from KC.
+- Add ability to call KC code from ASM. (maybe declare some functions external to ensure their interface is well defined. Maybe generate ASM call stubs.)
+- Add inline ASM (maybe?)
+
+Process/Code Structure Improvement
+- Make each phase return a separate object graph (allowing for keeping the history in memory & performing rollbacks)
+- Implemenent Assertions for the output of different phases (ensuring that the result of the phase is consistent)
+- Refactor Expression Operator Implementation & Evaluation into one class per operator
+
+Testing
+- Test that the parse tree for specific KC syntax is as expected. Use a print function for the parse tree to generate output for comparison.
+- Test the ICL result of a specific phase on a specific ICL input. Create an ICL syntax for parsing directly to ICL and a printer for the syntax.
+- Test the ASM program output resulting from compiling specific KC program input.
+- Emulate/Run the ASM for a specific KC program compiled. Compare the emulated ASM output to output calculated by executing directly on the KC tree.
+- Add assert statements to the language. Create KC programs that test the compiler by compiling, running and testing assertions.
+
+Optimizations
+- Optimize register allocation by combining with knowledge of ASM program cost (bytes/cycles) and different ASM fragments with different clobbering.
+- Optimize by finding optimal sequence for multiple phi assignments in entry-segments.
+- Optimize by allowing resequencing of statements and phi assignemtns in a final phase. Perhaps by converting phi statements to "normal" statements and using some optimization step.
+
+Usages
+- Implement library for memory allocation in main memory
+- Implement library for output on the screen (using basic functions)
+
+Real Usage
+- Implement library for fast multiply (mul.asm)
+- Implement spline library (spline.asm)
+- Implement polygon filler for complex polygons.
+- Implement true type font renderer.

src/dk/camelot64/kickc/asm/AsmFragment.java

@@ -127,7 +127,10 @@ public class AsmFragment {
       }
       if (conditionalJump.getRValue2() instanceof ConstantInteger && ((ConstantInteger) conditionalJump.getRValue2()).getNumber() == 0) {
          signature.append("0");
-      } else {
+      } else if (conditionalJump.getRValue2() instanceof ConstantBool) {
+         ConstantBool boolValue = (ConstantBool) conditionalJump.getRValue2();
+         signature.append(boolValue.toString());
+      } else{
          signature.append(bind(conditionalJump.getRValue2()));
       }
       signature.append("_then_");
@@ -135,7 +138,7 @@ public class AsmFragment {
       ControlFlowBlock destinationBlock = graph.getBlock(destination);
       String destinationLabel = destination.getFullName();
       if (destinationBlock.hasPhiStatements()) {
-         destinationLabel = destination.getFullName() + "_from_" + block.getLabel().getFullName();
+         destinationLabel = (destinationBlock.getLabel().getLocalName() + "_from_" + block.getLabel().getLocalName()).replace('@', 'B').replace(':','_');
       }
       signature.append(bind(new Label(destinationLabel, destination.getScope(),false)));
       return signature.toString();
@@ -348,7 +351,7 @@ public class AsmFragment {
             bound = Integer.toString(boundInt.getNumber());
          }
       } else if (boundValue instanceof Label) {
-         bound = ((Label) boundValue).getFullName().replace('@', 'B');
+         bound = ((Label) boundValue).getFullName().replace('@', 'B').replace(':','_');
       } else {
          throw new RuntimeException("Bound Value Type not implemented " + boundValue);
       }

src/dk/camelot64/kickc/asm/fragment/coptr1=zpby1.asm

@@ -0,0 +1,2 @@
+lda {zpby1}
+sta {coptr1}

src/dk/camelot64/kickc/asm/fragment/ptr_cowo1_xby=xby.asm

@@ -0,0 +1,2 @@
+txa
+sta {cowo1},x

src/dk/camelot64/kickc/asm/fragment/ptr_cowo1_yby=aby.asm

@@ -0,0 +1 @@
+sta {cowo1},y

src/dk/camelot64/kickc/asm/fragment/ptr_cowo1_zpby1=zpby1.asm

@@ -0,0 +1,3 @@
+ldy {zpby1}
+tya
+sta {cowo1},y

src/dk/camelot64/kickc/asm/fragment/ptr_zpptrby1_yby=aby.asm

@@ -0,0 +1 @@
+sta ({zpptrby1}),y

src/dk/camelot64/kickc/asm/fragment/ptr_zpptrby1_zpby1=zpby2.asm

@@ -0,0 +1,3 @@
+lda {zpby2}
+ldy {zpby1}
+sta ({zpptrby1}),y

src/dk/camelot64/kickc/asm/fragment/true_then_la1.asm

@@ -0,0 +1 @@
+jmp {la1}

src/dk/camelot64/kickc/asm/fragment/yby=yby_plus_1.asm

@@ -0,0 +1 @@
+iny

src/dk/camelot64/kickc/asm/fragment/yby_lt_coby1_then_la1.asm

@@ -0,0 +1,2 @@
+cpy #{coby1}
+bcc {la1}

src/dk/camelot64/kickc/asm/fragment/zpby1=cowo1_staridx_zpby2.asm

@@ -0,0 +1,3 @@
+ldy {zpby2}
+lda {cowo1},y
+sta {zpby1}

src/dk/camelot64/kickc/asm/fragment/zpby1=xby.asm

@@ -0,0 +1 @@
+stx {zpby1}

src/dk/camelot64/kickc/asm/fragment/zpby1_neq_0_then_la1.asm

@@ -0,0 +1,2 @@
+lda {zpby1}
+bne {la1}

src/dk/camelot64/kickc/icl/Pass1GenerateStatementSequence.java

@@ -151,7 +151,9 @@ public class Pass1GenerateStatementSequence extends KickCBaseVisitor<Object> {
       }
       procedure.setParameters(parameterList);
       sequence.addStatement(new StatementProcedureBegin(procedure));
-      this.visit(ctx.stmtSeq());
+      if(ctx.stmtSeq()!=null) {
+         this.visit(ctx.stmtSeq());
+      }
       sequence.addStatement(new StatementLabel(procExit));
       if(returnVar!=null) {
          sequence.addStatement(new StatementAssignment(returnVar, returnVar));
@@ -285,7 +287,13 @@ public class Pass1GenerateStatementSequence extends KickCBaseVisitor<Object> {
 
    @Override
    public Object visitExprCall(KickCParser.ExprCallContext ctx) {
-      List<RValue> parameters = (List<RValue>) this.visit(ctx.parameterList());
+      List<RValue> parameters;
+      KickCParser.ParameterListContext parameterList = ctx.parameterList();
+      if(parameterList!=null) {
+          parameters = (List<RValue>) this.visit(parameterList);
+      } else {
+         parameters = new ArrayList<>();
+      }
       VariableIntermediate tmpVar = getCurrentSymbols().addVariableIntermediate();
       sequence.addStatement(new StatementCall(tmpVar, ctx.NAME().getText(), parameters));
       return tmpVar;

src/dk/camelot64/kickc/icl/Pass1ProcedureCallParameters.java

@@ -38,7 +38,9 @@ public class Pass1ProcedureCallParameters extends ControlFlowGraphCopyVisitor {
       addStatementToCurrentBlock(copyCall);
       getCurrentBlock().setCallSuccessor(procedure.getLabel());
       splitCurrentBlock(scope.addLabelIntermediate());
-      addStatementToCurrentBlock(new StatementAssignment(origCall.getLValue(), procReturnVar));
+      if(!SymbolTypeBasic.VOID.equals(procedure.getReturnType())) {
+         addStatementToCurrentBlock(new StatementAssignment(origCall.getLValue(), procReturnVar));
+      }
       return null;
    }
 

src/dk/camelot64/kickc/icl/Pass1ProcedureCallsReturnValue.java

@@ -28,25 +28,26 @@ public class Pass1ProcedureCallsReturnValue extends ControlFlowGraphCopyVisitor
       copyCall.setProcedure(procedure);
       addStatementToCurrentBlock(copyCall);
       getCurrentBlock().setCallSuccessor(procedure.getLabel());
-
-      // Find return variable final version
-      Label returnBlockLabel = procedure.getLabel("@return");
-      ControlFlowBlock returnBlock = graph.getBlock(returnBlockLabel);
-      VariableVersion returnVarFinal = null;
-      for (Statement statement : returnBlock.getStatements()) {
-         if (statement instanceof StatementReturn) {
-            StatementReturn statementReturn = (StatementReturn) statement;
-            RValue returnValue = statementReturn.getValue();
-            if (returnValue instanceof VariableVersion) {
-               returnVarFinal = (VariableVersion) returnValue;
+      if(!SymbolTypeBasic.VOID.equals(procedure.getReturnType())) {
+         // Find return variable final version
+         Label returnBlockLabel = procedure.getLabel("@return");
+         ControlFlowBlock returnBlock = graph.getBlock(returnBlockLabel);
+         VariableVersion returnVarFinal = null;
+         for (Statement statement : returnBlock.getStatements()) {
+            if (statement instanceof StatementReturn) {
+               StatementReturn statementReturn = (StatementReturn) statement;
+               RValue returnValue = statementReturn.getValue();
+               if (returnValue instanceof VariableVersion) {
+                  returnVarFinal = (VariableVersion) returnValue;
+               }
             }
          }
+         if (returnVarFinal == null) {
+            throw new RuntimeException("Error! Cannot find final return variable for " + procedure.getFullName());
+         }
+         StatementAssignment returnAssignment = new StatementAssignment(origCall.getLValue(), returnVarFinal);
+         addStatementToCurrentBlock(returnAssignment);
       }
-      if (returnVarFinal == null) {
-         throw new RuntimeException("Error! Cannot find final return variable for " + procedure.getFullName());
-      }
-      StatementAssignment returnAssignment = new StatementAssignment(origCall.getLValue(), returnVarFinal);
-      addStatementToCurrentBlock(returnAssignment);
       return null;
    }
 

src/dk/camelot64/kickc/icl/Pass2ConstantAdditionElimination.java

@@ -59,6 +59,14 @@ public class Pass2ConstantAdditionElimination extends Pass2SsaOptimization {
 
    private boolean optimizePointerDereferenceIndexed(StatementAssignment assignment) {
       PointerDereferenceIndexed pointerDereferenceIndexed = (PointerDereferenceIndexed) assignment.getLValue();
+      if(pointerDereferenceIndexed.getPointer() instanceof ConstantInteger && pointerDereferenceIndexed.getIndex() instanceof Constant) {
+         ConstantInteger ptrConstant = (ConstantInteger) pointerDereferenceIndexed.getPointer();
+         ConstantInteger idxConstant = (ConstantInteger) pointerDereferenceIndexed.getIndex();
+         int newPtr = ptrConstant.getNumber() + idxConstant.getNumber();
+         assignment.setLValue(new PointerDereferenceSimple(new ConstantInteger(newPtr)));
+         System.out.println("Consolidated assigned array index constant in assignment " + assignment.getLValue());
+         return true;
+      }
       if(pointerDereferenceIndexed.getPointer() instanceof ConstantInteger && pointerDereferenceIndexed.getIndex() instanceof Variable) {
          Variable variable = (Variable) pointerDereferenceIndexed.getIndex();
          ConstantInteger consolidated = consolidateSubConstants(variable);
@@ -74,13 +82,23 @@ public class Pass2ConstantAdditionElimination extends Pass2SsaOptimization {
    }
 
    private boolean optimizeArrayDeref(StatementAssignment assignment) {
+      if (assignment.getRValue1() instanceof ConstantInteger && assignment.getRValue2() instanceof ConstantInteger) {
+         ConstantInteger ptrConstant = (ConstantInteger) assignment.getRValue1();
+         ConstantInteger idxConstant = (ConstantInteger) assignment.getRValue2();
+         int newPtr = ptrConstant.getNumber() + idxConstant.getNumber();
+         assignment.setRValue1(null);
+         assignment.setOperator(new Operator("*"));
+         assignment.setRValue2(new ConstantInteger(newPtr));
+         System.out.println("Consolidated referenced array index constant in assignment " + assignment.getLValue());
+         return true;
+      }
       if (assignment.getRValue1() instanceof ConstantInteger && assignment.getRValue2() instanceof Variable) {
          Variable variable = (Variable) assignment.getRValue2();
          ConstantInteger consolidated = consolidateSubConstants(variable);
          if (consolidated != null) {
             ConstantInteger ptrConstant = (ConstantInteger) assignment.getRValue1();
             int newPtr = ptrConstant.getNumber() + consolidated.getNumber();
-               assignment.setRValue1(new ConstantInteger(newPtr));
+            assignment.setRValue1(new ConstantInteger(newPtr));
             System.out.println("Consolidated referenced array index constant in assignment " + assignment.getLValue());
             return true;
          }
@@ -124,7 +142,7 @@ public class Pass2ConstantAdditionElimination extends Pass2SsaOptimization {
     * @return The consolidated constant. Null if no sub-constants were found.
     */
    private ConstantInteger consolidateSubConstants(Variable variable) {
-      if(usages.get(variable)>1) {
+      if(getUsages(variable) >1) {
          System.out.println("Multiple usages for variable. Not optimizing sub-constant "+variable);
          return null;
       }
@@ -197,4 +215,10 @@ public class Pass2ConstantAdditionElimination extends Pass2SsaOptimization {
       return null;
    }
 
+   private Integer getUsages(Variable variable) {
+      Integer useCount = usages.get(variable);
+      if(useCount==null) useCount = 0;
+      return useCount;
+   }
+
 }

src/dk/camelot64/kickc/icl/Pass2ConstantPropagation.java

@@ -56,7 +56,9 @@ public class Pass2ConstantPropagation extends Pass2SsaOptimization {
                         assignment.getOperator(),
                         (Constant) assignment.getRValue1(),
                         (Constant) assignment.getRValue2());
-                  constants.put(variable, constant);
+                  if(constant!=null) {
+                     constants.put(variable, constant);
+                  }
                }
             }
             return null;
@@ -110,6 +112,10 @@ public class Pass2ConstantPropagation extends Pass2SsaOptimization {
                return new ConstantDouble(getDouble(c1) / getDouble(c2));
             }
          }
+         case "*idx": {
+            // Cannot be directly propagated
+            return null;
+         }
          default:
             throw new RuntimeException("Unhandled Binary Operator " + operator.getOperator());
       }

src/dk/camelot64/kickc/icl/Pass3BlockSequencePlanner.java

@@ -26,7 +26,7 @@ public class Pass3BlockSequencePlanner {
          }
          if(sequence.contains(block)) {
             // already handled - move on
-            break;
+            continue;
          }
          sequence.add(block);
          if(block.getCallSuccessor()!=null) {

src/dk/camelot64/kickc/icl/Pass3RegisterAllocation.java

@@ -17,34 +17,40 @@ public class Pass3RegisterAllocation {
    public void allocate() {
       RegisterAllocation allocation = new RegisterAllocation();
       performAllocation(symbols, allocation);
-      allocation.allocate(symbols.getVariable("i#0"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("i#1"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("i#2"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("i#3"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("i#4"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("i#5"), RegisterAllocation.getRegisterX());
-      allocation.allocate(symbols.getVariable("n1#1"), RegisterAllocation.getRegisterY());
-      allocation.allocate(symbols.getVariable("n1#2"), RegisterAllocation.getRegisterY());
-      allocation.allocate(symbols.getVariable("e#2"), new RegisterAllocation.RegisterZpByte(128));
-      allocation.allocate(symbols.getVariable("e#3"), new RegisterAllocation.RegisterZpByte(128));
-      allocation.allocate(symbols.getVariable("e#4"), new RegisterAllocation.RegisterZpByte(128));
-      allocation.allocate(symbols.getVariable("e#5"), new RegisterAllocation.RegisterZpByte(128));
-      allocation.allocate(symbols.getVariable("idx#2"), new RegisterAllocation.RegisterZpWord(129));
-      allocation.allocate(symbols.getVariable("idx#3"), new RegisterAllocation.RegisterZpWord(129));
-      allocation.allocate(symbols.getVariable("idx#4"), new RegisterAllocation.RegisterZpWord(129));
-      allocation.allocate(symbols.getVariable("idx#5"), new RegisterAllocation.RegisterZpWord(129));
-      allocation.allocate(symbols.getVariable("x#2"), new RegisterAllocation.RegisterZpByte(131));
-      allocation.allocate(symbols.getVariable("x#5"), new RegisterAllocation.RegisterZpByte(131));
-      allocation.allocate(symbols.getVariable("y#1"), new RegisterAllocation.RegisterZpByte(132));
-      allocation.allocate(symbols.getVariable("y#2"), new RegisterAllocation.RegisterZpByte(132));
-      allocation.allocate(symbols.getVariable("y#5"), new RegisterAllocation.RegisterZpByte(132));
-      allocation.allocate(symbols.getVariable("cursor#2"), new RegisterAllocation.RegisterZpPointerByte(133));
-      allocation.allocate(symbols.getVariable("cursor#3"), new RegisterAllocation.RegisterZpPointerByte(133));
-      allocation.allocate(symbols.getVariable("cursor#4"), new RegisterAllocation.RegisterZpPointerByte(133));
-      allocation.allocate(symbols.getVariable("cursor#5"), new RegisterAllocation.RegisterZpPointerByte(133));
-      allocation.allocate(symbols.getVariable("ptr#1"), new RegisterAllocation.RegisterZpPointerByte(135));
-      allocation.allocate(symbols.getVariable("ptr#2"), new RegisterAllocation.RegisterZpPointerByte(135));
-      allocation.allocate(symbols.getVariable("ptr#3"), new RegisterAllocation.RegisterZpPointerByte(135));
+
+      //allocation.allocate(symbols.getVariable("i#0"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#1"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#2"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#3"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#4"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#5"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#6"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("i#7"), RegisterAllocation.getRegisterX());
+      //allocation.allocate(symbols.getVariable("n1#1"), RegisterAllocation.getRegisterY());
+      //allocation.allocate(symbols.getVariable("n1#2"), RegisterAllocation.getRegisterY());
+      //allocation.allocate(symbols.getVariable("e#2"), new RegisterAllocation.RegisterZpByte(128));
+      //allocation.allocate(symbols.getVariable("e#3"), new RegisterAllocation.RegisterZpByte(128));
+      //allocation.allocate(symbols.getVariable("e#4"), new RegisterAllocation.RegisterZpByte(128));
+      //allocation.allocate(symbols.getVariable("e#5"), new RegisterAllocation.RegisterZpByte(128));
+      //allocation.allocate(symbols.getVariable("idx#2"), new RegisterAllocation.RegisterZpWord(129));
+      //allocation.allocate(symbols.getVariable("idx#3"), new RegisterAllocation.RegisterZpWord(129));
+      //allocation.allocate(symbols.getVariable("idx#4"), new RegisterAllocation.RegisterZpWord(129));
+      //allocation.allocate(symbols.getVariable("idx#5"), new RegisterAllocation.RegisterZpWord(129));
+      //allocation.allocate(symbols.getVariable("x#0"), new RegisterAllocation.RegisterYByte());
+      //allocation.allocate(symbols.getVariable("x#1"), new RegisterAllocation.RegisterYByte());
+      //allocation.allocate(symbols.getVariable("x#2"), new RegisterAllocation.RegisterYByte());
+      //allocation.allocate(symbols.getVariable("x#5"), new RegisterAllocation.RegisterZpByte(131));
+      //allocation.allocate(symbols.getVariable("y#0"), new RegisterAllocation.RegisterZpByte(132));
+      //allocation.allocate(symbols.getVariable("y#1"), new RegisterAllocation.RegisterZpByte(132));
+      //allocation.allocate(symbols.getVariable("y#2"), new RegisterAllocation.RegisterZpByte(132));
+      //allocation.allocate(symbols.getVariable("y#5"), new RegisterAllocation.RegisterZpByte(132));
+      //allocation.allocate(symbols.getVariable("cursor#2"), new RegisterAllocation.RegisterZpPointerByte(133));
+      //allocation.allocate(symbols.getVariable("cursor#3"), new RegisterAllocation.RegisterZpPointerByte(133));
+      //allocation.allocate(symbols.getVariable("cursor#4"), new RegisterAllocation.RegisterZpPointerByte(133));
+      //allocation.allocate(symbols.getVariable("cursor#5"), new RegisterAllocation.RegisterZpPointerByte(133));
+      //allocation.allocate(symbols.getVariable("ptr#1"), new RegisterAllocation.RegisterZpPointerByte(135));
+      //allocation.allocate(symbols.getVariable("ptr#2"), new RegisterAllocation.RegisterZpPointerByte(135));
+      //allocation.allocate(symbols.getVariable("ptr#3"), new RegisterAllocation.RegisterZpPointerByte(135));
       //allocation.allocate(symbols.getVariable("v#1"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("v#2"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("v#3"), new RegisterAllocation.RegisterAByte());
@@ -56,14 +62,39 @@ public class Pass3RegisterAllocation {
       //allocation.allocate(symbols.getVariable("$1"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("$3"), new RegisterAllocation.RegisterALUByte());
       //allocation.allocate(symbols.getVariable("$4"), new RegisterAllocation.RegisterAByte());
+      //allocation.allocate(symbols.getVariable("$5"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("$6"), new RegisterAllocation.RegisterALUByte());
       //allocation.allocate(symbols.getVariable("$7"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("inc::a#2"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("bv#0"), new RegisterAllocation.RegisterAByte());
-      allocation.allocate(symbols.getVariable("sum::b#0"), new RegisterAllocation.RegisterAByte());
-      allocation.allocate(symbols.getVariable("inc::b#1"), new RegisterAllocation.RegisterAByte());
+      //allocation.allocate(symbols.getVariable("sum::b#0"), new RegisterAllocation.RegisterAByte());
+      //allocation.allocate(symbols.getVariable("inc::b#1"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("a#1"), new RegisterAllocation.RegisterAByte());
       //allocation.allocate(symbols.getVariable("a#0"), new RegisterAllocation.RegisterAByte());
+
+      allocation.allocate(symbols.getVariable("plot::i#0"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("plot::i#1"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("plot::i#2"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("plot::i#3"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("plot::i#4"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("plot::x#0"), RegisterAllocation.getRegisterY());
+      allocation.allocate(symbols.getVariable("plot::x#1"), RegisterAllocation.getRegisterY());
+      allocation.allocate(symbols.getVariable("plot::x#2"), RegisterAllocation.getRegisterY());
+      allocation.allocate(symbols.getVariable("plot::y#0"), new RegisterAllocation.RegisterZpByte(100));
+      allocation.allocate(symbols.getVariable("plot::y#1"), new RegisterAllocation.RegisterZpByte(100));
+      allocation.allocate(symbols.getVariable("plot::y#2"), new RegisterAllocation.RegisterZpByte(100));
+      allocation.allocate(symbols.getVariable("plot::y#3"), new RegisterAllocation.RegisterZpByte(100));
+      allocation.allocate(symbols.getVariable("plot::y#4"), new RegisterAllocation.RegisterZpByte(100));
+      allocation.allocate(symbols.getVariable("plot::line#0"), new RegisterAllocation.RegisterZpPointerByte(101));
+      allocation.allocate(symbols.getVariable("plot::line#1"), new RegisterAllocation.RegisterZpPointerByte(101));
+      allocation.allocate(symbols.getVariable("plot::line#2"), new RegisterAllocation.RegisterZpPointerByte(101));
+      allocation.allocate(symbols.getVariable("plot::line#3"), new RegisterAllocation.RegisterZpPointerByte(101));
+      allocation.allocate(symbols.getVariable("plot::line#4"), new RegisterAllocation.RegisterZpPointerByte(101));
+      allocation.allocate(symbols.getVariable("plot::$3"), RegisterAllocation.getRegisterA());
+      allocation.allocate(symbols.getVariable("prepare::i#0"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("prepare::i#1"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("prepare::i#2"), RegisterAllocation.getRegisterX());
+
       symbols.setAllocation(allocation);
 
    }

src/dk/camelot64/kickc/icl/PointerDereferenceSimple.java

@@ -5,7 +5,7 @@ public class PointerDereferenceSimple implements PointerDereference {
 
    private RValue pointer;
 
-   public PointerDereferenceSimple(Variable pointer) {
+   public PointerDereferenceSimple(RValue pointer) {
       this.pointer = pointer;
    }
 

src/dk/camelot64/kickc/icl/SymbolTypeBasic.java

@@ -29,6 +29,7 @@ public enum SymbolTypeBasic implements SymbolType {
          case "word": return WORD;
          case "string": return STRING;
          case "boolean": return BOOLEAN;
+         case "void": return VOID;
       }
       return null;
    }

src/dk/camelot64/kickc/test/Main.java

@@ -13,7 +13,7 @@ import java.util.List;
 /** Test my KickC Grammar */
 public class Main {
    public static void main(String[] args) throws IOException {
-      final String fileName = "src/dk/camelot64/kickc/test/callsum.kc";
+      final String fileName = "src/dk/camelot64/kickc/test/flipper-rex2.kc";
       final CharStream input = CharStreams.fromFileName(fileName);
       System.out.println(input.toString());
       KickCLexer lexer = new KickCLexer(input);

src/dk/camelot64/kickc/test/flipper-rex2.kc

@@ -0,0 +1,39 @@
+byte[1000] SCREEN = $0400;
+byte[16*16] buffer = $1000;
+byte[16*16] buffer2 = $1100;
+
+prepare();
+do {
+   plot();
+   flip();
+} while(true)
+
+void prepare() {
+   // Prepare buffer
+   byte i=0;
+   do {
+      buffer[i] = i;
+      i=i+1;
+   } while (i!=0)
+}
+
+void flip() {
+   // Flip buffer
+}
+
+// Plot buffer on screen
+void plot() {
+   byte* line = SCREEN+5*40+12;
+   byte y=0;
+   byte i=0;
+   do {
+      byte x=0;
+      do {
+         line[x] = buffer[i];
+         x=x+1;
+         i=i+1;
+      } while(x<16)
+      line = line+40;
+      y=y+1;
+   } while(y<16)
+}