diff --git a/src/main/java/dk/camelot64/kickc/model/Registers.java b/src/main/java/dk/camelot64/kickc/model/Registers.java
index a8d931a17..aed370e3b 100644
--- a/src/main/java/dk/camelot64/kickc/model/Registers.java
+++ b/src/main/java/dk/camelot64/kickc/model/Registers.java
@@ -16,32 +16,19 @@ public class Registers {
       return new RegisterAByte();
    }
 
-   public static Register getRegisterASigned() {
-      return new RegisterASignedByte();
-   }
-
-   public static Register getRegisterXSigned() {
-      return new RegisterXSignedByte();
-   }
-
-   public static Register getRegisterYSigned() {
-      return new RegisterYSignedByte();
-   }
-
    public static Register getRegisterALU() {
       return new RegisterALUByte();
    }
 
    /** The register type. */
    public enum RegisterType {
-      REG_A_BYTE, REG_A_SBYTE,
-      REG_Y_BYTE, REG_Y_SBYTE,
-      REG_X_BYTE, REG_X_SBYTE,
+      REG_A_BYTE,
+      REG_Y_BYTE,
+      REG_X_BYTE,
       REG_ALU,
-      ZP_BYTE, ZP_SBYTE,
+      ZP_BYTE,
       ZP_PTR_BYTE,
       ZP_WORD,
-      ZP_SWORD,
       ZP_BOOL,
       CONSTANT
    }
@@ -117,21 +104,6 @@ public class Registers {
       }
 
 
-   }
-
-   /** A zero page address used as a register for a single signed byte variable. */
-   public static class RegisterZpSignedByte extends RegisterZp {
-
-      public RegisterZpSignedByte(int zp) {
-         super(zp);
-      }
-
-      @Override
-      public RegisterType getType() {
-         return RegisterType.ZP_SBYTE;
-      }
-
-
    }
 
    /** Two zero page addresses used as a register for a single unsigned word variable. */
@@ -148,20 +120,6 @@ public class Registers {
 
    }
 
-   /** Two zero page addresses used as a register for a single signed word variable. */
-   public static class RegisterZpSWord extends RegisterZp {
-
-      public RegisterZpSWord(int zp) {
-         super(zp);
-      }
-
-      @Override
-      public RegisterType getType() {
-         return RegisterType.ZP_SWORD;
-      }
-
-   }
-
 
    /** A zero page address used as a register for a boolean variable. */
    public static class RegisterZpBool extends RegisterZp {
@@ -271,49 +229,6 @@ public class Registers {
 
    }
 
-   /** The A signed register. */
-   public static class RegisterASignedByte extends RegisterCpuByte {
-      @Override
-      public RegisterType getType() {
-         return RegisterType.REG_A_SBYTE;
-      }
-
-      @Override
-      public String toString() {
-         return "reg sbyte a";
-      }
-
-   }
-
-   /** The X signed register. */
-   public static class RegisterXSignedByte extends RegisterCpuByte {
-      @Override
-      public RegisterType getType() {
-         return RegisterType.REG_X_SBYTE;
-      }
-
-      @Override
-      public String toString() {
-         return "reg sbyte x";
-      }
-
-   }
-
-   /** The Y signed register. */
-   public static class RegisterYSignedByte extends RegisterCpuByte {
-      @Override
-      public RegisterType getType() {
-         return RegisterType.REG_Y_SBYTE;
-      }
-
-      @Override
-      public String toString() {
-         return "reg sbyte y";
-      }
-
-   }
-
-
    /** The special ALU register. */
    public static class RegisterALUByte extends RegisterCpuByte {
       @Override
diff --git a/src/main/java/dk/camelot64/kickc/passes/Pass4RegisterUpliftPotentialInitialize.java b/src/main/java/dk/camelot64/kickc/passes/Pass4RegisterUpliftPotentialInitialize.java
index c7731cbb1..57acf50af 100644
--- a/src/main/java/dk/camelot64/kickc/passes/Pass4RegisterUpliftPotentialInitialize.java
+++ b/src/main/java/dk/camelot64/kickc/passes/Pass4RegisterUpliftPotentialInitialize.java
@@ -30,13 +30,6 @@ public class Pass4RegisterUpliftPotentialInitialize extends Pass2Base {
                   Registers.getRegisterX(),
                   Registers.getRegisterY());
             registerPotentials.setPotentialRegisters(equivalenceClass, potentials);
-         } else if (registerType.equals(Registers.RegisterType.ZP_SBYTE)) {
-            List<Registers.Register> potentials = Arrays.asList(
-                  defaultRegister,
-                  Registers.getRegisterASigned(),
-                  Registers.getRegisterXSigned(),
-                  Registers.getRegisterYSigned());
-            registerPotentials.setPotentialRegisters(equivalenceClass, potentials);
          } else {
             registerPotentials.setPotentialRegisters(equivalenceClass, Arrays.asList(defaultRegister));
          }
diff --git a/src/main/java/dk/camelot64/kickc/passes/Pass4RegistersFinalize.java b/src/main/java/dk/camelot64/kickc/passes/Pass4RegistersFinalize.java
index bbaa05713..86b3e468f 100644
--- a/src/main/java/dk/camelot64/kickc/passes/Pass4RegistersFinalize.java
+++ b/src/main/java/dk/camelot64/kickc/passes/Pass4RegistersFinalize.java
@@ -144,10 +144,10 @@ public class Pass4RegistersFinalize extends Pass2Base {
          currentZp = currentZp + 2;
          return registerZpWord;
       } else if (SymbolType.isSWord(varType)) {
-         Registers.RegisterZpSWord registerZpSWord =
-               new Registers.RegisterZpSWord(currentZp);
+         Registers.RegisterZpWord registerZpWord =
+               new Registers.RegisterZpWord(currentZp);
          currentZp = currentZp + 2;
-         return registerZpSWord;
+         return registerZpWord;
       } else if (varType.equals(SymbolType.BOOLEAN)) {
          return new Registers.RegisterZpBool(currentZp++);
       } else if (varType.equals(SymbolType.VOID)) {