diff --git a/src/dk/camelot64/kickc/icl/AsmFragment.java b/src/dk/camelot64/kickc/icl/AsmFragment.java
index 1795cbe00..97a3d1f26 100644
--- a/src/dk/camelot64/kickc/icl/AsmFragment.java
+++ b/src/dk/camelot64/kickc/icl/AsmFragment.java
@@ -28,9 +28,15 @@ public class AsmFragment {
       StringBuilder signature = new StringBuilder();
       if(conditionalJump.getRValue1()!=null) {
          signature.append(bind(conditionalJump.getRValue1()));
+      }
+      if(conditionalJump.getOperator()!=null) {
          signature.append(conditionalJump.getOperator().getOperator());
       }
-      signature.append(bind(conditionalJump.getRValue2()));
+      if(conditionalJump.getRValue2() instanceof ConstantInteger && ((ConstantInteger) conditionalJump.getRValue2()).getNumber()==0) {
+         signature.append("0");
+      }  else {
+         signature.append(bind(conditionalJump.getRValue2()));
+      }
       signature.append("?");
       signature.append(bind(conditionalJump.getDestination()));
       setSignature(signature.toString());
@@ -58,7 +64,15 @@ public class AsmFragment {
       if (operator != null) {
          signature.append(operator.getOperator());
       }
-      signature.append(bind(rValue2));
+      if(
+            rValue2 instanceof ConstantInteger &&
+                  ((ConstantInteger) rValue2).getNumber()==1 &&
+                  operator!=null &&
+                  (operator.getOperator().equals("-") || operator.getOperator().equals("+"))) {
+         signature.append("1");
+      }  else {
+         signature.append(bind(rValue2));
+      }
       return signature.toString();
    }
 
@@ -108,6 +122,10 @@ public class AsmFragment {
             String name = "zpbo" + nextZpBoolIdx++;
             bindings.put(name, value);
             return name;
+         } else if (RegisterAllocation.RegisterType.REG_X_BYTE.equals(register.getType())) {
+            String name = "xby" ;
+            bindings.put(name, value);
+            return name;
          } else {
             throw new RuntimeException("Binding of register type not supported " + register.getType());
          }
diff --git a/src/dk/camelot64/kickc/icl/Pass3RegisterAllocation.java b/src/dk/camelot64/kickc/icl/Pass3RegisterAllocation.java
index 513dceebe..be44c4180 100644
--- a/src/dk/camelot64/kickc/icl/Pass3RegisterAllocation.java
+++ b/src/dk/camelot64/kickc/icl/Pass3RegisterAllocation.java
@@ -22,6 +22,10 @@ public class Pass3RegisterAllocation {
                allocation.allocate(var, new RegisterAllocation.RegisterZpBool(currentZp++));
             }
       }
+      allocation.allocate(symbols.getVariable("i#1"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("i#3"), RegisterAllocation.getRegisterX());
+      allocation.allocate(symbols.getVariable("n1#1"), new RegisterAllocation.RegisterZpByte(8));
+      allocation.allocate(symbols.getVariable("n1#2"), new RegisterAllocation.RegisterZpByte(8));
       symbols.setAllocation(allocation);
    }
 
diff --git a/src/dk/camelot64/kickc/icl/RegisterAllocation.java b/src/dk/camelot64/kickc/icl/RegisterAllocation.java
index 6b75100ae..ba86d0143 100644
--- a/src/dk/camelot64/kickc/icl/RegisterAllocation.java
+++ b/src/dk/camelot64/kickc/icl/RegisterAllocation.java
@@ -36,7 +36,7 @@ public class RegisterAllocation {
 
    /** The register type. */
    public enum RegisterType {
-      ZP_BYTE, ZP_BOOL
+      ZP_BYTE, ZP_BOOL, REG_X_BYTE
    };
 
    /** A zero page address used as a register for a single byte variable. */
@@ -86,6 +86,23 @@ public class RegisterAllocation {
       }
    }
 
+   /** The X register. */
+   public static class RegisterXByte implements Register {
+      @Override
+      public RegisterType getType() {
+         return RegisterType.REG_X_BYTE;
+      }
+
+      @Override
+      public String toString() {
+         return "reg byte x";
+      }
+   }
+
+   public static Register getRegisterX() {
+      return new RegisterXByte();
+   }
+
    @Override
    public String toString() {
       StringBuffer out = new StringBuffer();
diff --git a/src/dk/camelot64/kickc/icl/SymbolTable.java b/src/dk/camelot64/kickc/icl/SymbolTable.java
index 16a568ea6..ccd5e8105 100644
--- a/src/dk/camelot64/kickc/icl/SymbolTable.java
+++ b/src/dk/camelot64/kickc/icl/SymbolTable.java
@@ -1,5 +1,7 @@
 package dk.camelot64.kickc.icl;
 
+import sun.jvm.hotspot.debugger.cdbg.Sym;
+
 import java.util.*;
 
 /**
@@ -75,6 +77,10 @@ public class SymbolTable {
       return version;
    }
 
+   public Variable getVariable(String name) {
+      return (Variable) symbols.get(name);
+   }
+
    public void setAllocation(RegisterAllocation allocation) {
       this.allocation = allocation;
    }
diff --git a/src/dk/camelot64/kickc/icl/asm/xby=coby1.asm b/src/dk/camelot64/kickc/icl/asm/xby=coby1.asm
new file mode 100644
index 000000000..8bc1f4465
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/xby=coby1.asm
@@ -0,0 +1 @@
+ldx #{coby1}
\ No newline at end of file
diff --git a/src/dk/camelot64/kickc/icl/asm/xby=xby-1.asm b/src/dk/camelot64/kickc/icl/asm/xby=xby-1.asm
new file mode 100644
index 000000000..23e2d0ff8
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/xby=xby-1.asm
@@ -0,0 +1 @@
+dex
\ No newline at end of file
diff --git a/src/dk/camelot64/kickc/icl/asm/xby=xby.asm b/src/dk/camelot64/kickc/icl/asm/xby=xby.asm
new file mode 100644
index 000000000..1ab91fbaf
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/xby=xby.asm
@@ -0,0 +1 @@
+// x=x
\ No newline at end of file
diff --git a/src/dk/camelot64/kickc/icl/asm/xby>0?la1.asm b/src/dk/camelot64/kickc/icl/asm/xby>0?la1.asm
new file mode 100644
index 000000000..0f99f0508
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/xby>0?la1.asm
@@ -0,0 +1,2 @@
+cpx #0
+bne {la1}
\ No newline at end of file
diff --git a/src/dk/camelot64/kickc/icl/asm/zpby1>0?la1.asm b/src/dk/camelot64/kickc/icl/asm/zpby1>0?la1.asm
new file mode 100644
index 000000000..4c6ddba5c
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/zpby1>0?la1.asm
@@ -0,0 +1,2 @@
+lda {zpby1}
+bne {la1}
diff --git a/src/dk/camelot64/kickc/icl/asm/zpby1>coby1?la1.asm b/src/dk/camelot64/kickc/icl/asm/zpby1>coby1?la1.asm
new file mode 100644
index 000000000..7da7bd205
--- /dev/null
+++ b/src/dk/camelot64/kickc/icl/asm/zpby1>coby1?la1.asm
@@ -0,0 +1,5 @@
+lda {zpby1}
+cmp #{coby1}
+beq !+
+bcs {la1}
+!:
\ No newline at end of file
diff --git a/src/dk/camelot64/kickc/test/fib.kc b/src/dk/camelot64/kickc/test/fib.kc
index 0532b60a7..8e1de3fc1 100644
--- a/src/dk/camelot64/kickc/test/fib.kc
+++ b/src/dk/camelot64/kickc/test/fib.kc
@@ -1,10 +1,10 @@
 byte n1 = 0;
 byte n2 = 1;
-byte i = 0;
+byte i = 12;
 byte fib = 0;
-while(i<=11) {
+while(i>0) {
     fib = n1 + n2;
     n1 = n2;
     n2 = fib;
-    i = i + 1;
+    i = i - 1;
 }