diff --git a/src/main/fragment/mos6502-common/_stackgetbyte_vbuc1=vbuaa.asm b/src/main/fragment/mos6502-common/_stackgetbyte_vbuc1=vbuaa.asm
new file mode 100644
index 000000000..a950d1216
--- /dev/null
+++ b/src/main/fragment/mos6502-common/_stackgetbyte_vbuc1=vbuaa.asm
@@ -0,0 +1,2 @@
+tsx
+sta STACK_BASE+{c1},x
\ No newline at end of file
diff --git a/src/main/fragment/mos6502-common/_stackgetword_vbuc1=vwuz1.asm b/src/main/fragment/mos6502-common/_stackgetword_vbuc1=vwuz1.asm
new file mode 100644
index 000000000..568ff503a
--- /dev/null
+++ b/src/main/fragment/mos6502-common/_stackgetword_vbuc1=vwuz1.asm
@@ -0,0 +1,5 @@
+tsx
+lda {z1}
+sta STACK_BASE+{c1},x
+lda {z1}+1
+sta STACK_BASE+{c1}+1,x
diff --git a/src/main/java/dk/camelot64/kickc/model/values/ParamStackPull.java b/src/main/java/dk/camelot64/kickc/model/values/ParamStackPull.java
index 0e99f0a5a..6d40f290a 100644
--- a/src/main/java/dk/camelot64/kickc/model/values/ParamStackPull.java
+++ b/src/main/java/dk/camelot64/kickc/model/values/ParamStackPull.java
@@ -3,7 +3,7 @@ package dk.camelot64.kickc.model.values;
 import dk.camelot64.kickc.model.Program;
 import dk.camelot64.kickc.model.types.SymbolType;
 
-/** A value puslled from the stack. */
+/** A value pulled from the stack. */
 public class ParamStackPull implements RValue {
 
    /** The type of value being pushed. */
diff --git a/src/main/java/dk/camelot64/kickc/model/values/ParamStackValue.java b/src/main/java/dk/camelot64/kickc/model/values/ParamStackValue.java
index 191989505..0a74ccdf3 100644
--- a/src/main/java/dk/camelot64/kickc/model/values/ParamStackValue.java
+++ b/src/main/java/dk/camelot64/kickc/model/values/ParamStackValue.java
@@ -4,24 +4,24 @@ import dk.camelot64.kickc.model.Program;
 import dk.camelot64.kickc.model.types.SymbolType;
 
 /** The value passed into a function for a specific parameter using the stack. */
-public class ParamStackValue implements RValue {
+public class ParamStackValue implements LValue {
 
    /** The constant holding the stack offset of the parameter. */
-   private ConstantRef stackOffset;
+   private ConstantValue stackOffset;
 
    /** The type of the value to fetch from the stack. */
    private SymbolType valueType;
 
-   public ParamStackValue(ConstantRef stackOffset, SymbolType valueType) {
+   public ParamStackValue(ConstantValue stackOffset, SymbolType valueType) {
       this.stackOffset = stackOffset;
       this.valueType = valueType;
    }
 
-   public ConstantRef getStackOffset() {
+   public ConstantValue getStackOffset() {
       return stackOffset;
    }
 
-   public void setStackOffset(ConstantRef stackOffset) {
+   public void setStackOffset(ConstantValue stackOffset) {
       this.stackOffset = stackOffset;
    }
 
@@ -35,7 +35,8 @@ public class ParamStackValue implements RValue {
 
    @Override
    public String toString(Program program) {
-      return "paramstack("+valueType.getTypeName()+","+stackOffset+")";
+      return "paramstack("+valueType.getTypeName()+","+stackOffset.toString(program)+")";
    }
 
+
 }
diff --git a/src/main/java/dk/camelot64/kickc/passes/Pass4CodeGeneration.java b/src/main/java/dk/camelot64/kickc/passes/Pass4CodeGeneration.java
index 1c42b3188..4f050ce53 100644
--- a/src/main/java/dk/camelot64/kickc/passes/Pass4CodeGeneration.java
+++ b/src/main/java/dk/camelot64/kickc/passes/Pass4CodeGeneration.java
@@ -801,18 +801,37 @@ public class Pass4CodeGeneration {
 
             }
          } else if(statement instanceof StatementReturn) {
-            Procedure.InterruptType interruptType = null;
+            Procedure procedure = null;
             ScopeRef scope = block.getScope();
             if(!scope.equals(ScopeRef.ROOT)) {
-               Procedure procedure = getScope().getProcedure(scope.getFullName());
-               if(procedure != null) {
-                  interruptType = procedure.getInterruptType();
+               procedure = getScope().getProcedure(scope.getFullName());
+            }
+
+            if(procedure!=null && Procedure.CallingConvension.STACK_CALL.equals(procedure.getCallingConvension())) {
+               StatementReturn returnStatement = (StatementReturn) statement;
+               if(returnStatement.getValue()!=null) {
+                  // Store return value on stack
+                  SymbolType returnType = procedure.getReturnType();
+
+                  // Find parameter/return stack size
+                  int parameterBytes = 0;
+                  for(Variable parameter : procedure.getParameters()) {
+                     parameterBytes += parameter.getType().getSizeBytes();
+                  }
+                  int returnOffset = parameterBytes - returnType.getSizeBytes();
+                  // TODO: Put the return stack offset into a named constant (look at PassNCallingConventionStack)
+                  ConstantValue returnValueStackOffset = new ConstantInteger((long)returnOffset, SymbolType.BYTE);
+                  AsmFragmentInstanceSpecFactory asmFragmentInstanceSpecFactory = new AsmFragmentInstanceSpecFactory(new ParamStackValue(returnValueStackOffset, returnType), returnStatement.getValue(), program, block.getScope());
+                  asm.startChunk(block.getScope(), statement.getIndex(), statement.toString(program, verboseAliveInfo));
+                  ensureEncoding(asm, asmFragmentInstanceSpecFactory);
+                  generateAsm(asm, asmFragmentInstanceSpecFactory.getAsmFragmentInstanceSpec());
                }
             }
-            if(interruptType == null) {
+
+            if(procedure==null || procedure.getInterruptType() == null) {
                asm.addInstruction("rts", AsmAddressingMode.NON, null, false);
             } else {
-               generateInterruptExit(asm, statement, interruptType);
+               generateInterruptExit(asm, statement, procedure.getInterruptType());
             }
          } else if(statement instanceof StatementAsm) {
             StatementAsm statementAsm = (StatementAsm) statement;
diff --git a/src/test/ref/procedure-callingconvention-stack-0.asm b/src/test/ref/procedure-callingconvention-stack-0.asm
index b061638cc..3293ed5f3 100644
--- a/src/test/ref/procedure-callingconvention-stack-0.asm
+++ b/src/test/ref/procedure-callingconvention-stack-0.asm
@@ -27,5 +27,7 @@ plus: {
     lda STACK_BASE+OFFSET_STACK_B,x
     clc
     adc.z a
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
diff --git a/src/test/ref/procedure-callingconvention-stack-0.cfg b/src/test/ref/procedure-callingconvention-stack-0.cfg
index 7d27d5cc1..37c87d1a7 100644
--- a/src/test/ref/procedure-callingconvention-stack-0.cfg
+++ b/src/test/ref/procedure-callingconvention-stack-0.cfg
@@ -22,8 +22,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
diff --git a/src/test/ref/procedure-callingconvention-stack-0.log b/src/test/ref/procedure-callingconvention-stack-0.log
index 121a292ec..9f72690c7 100644
--- a/src/test/ref/procedure-callingconvention-stack-0.log
+++ b/src/test/ref/procedure-callingconvention-stack-0.log
@@ -90,8 +90,8 @@ Adding NOP phi() at start of @1
 Adding NOP phi() at start of @end
 Adding NOP phi() at start of main
 Calling convention STACK_CALL adding prepare/execute/finalize for [5] (byte~) main::$0 ← call plus (byte) '0' (byte) 7 
-Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,plus::OFFSET_STACK_A)
-Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,plus::OFFSET_STACK_B)
+Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,(const byte) plus::OFFSET_STACK_B)
 
 FINAL CONTROL FLOW GRAPH
 @begin: scope:[]  from
@@ -118,8 +118,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
@@ -217,11 +217,11 @@ plus: {
     .label a = 3
     .label b = 4
     .label return = 5
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -234,6 +234,10 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuz1 
+    lda.z return
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -241,16 +245,18 @@ plus: {
 REGISTER UPLIFT POTENTIAL REGISTERS
 Statement [5] callprepare plus (byte) '0' (byte) 7  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (byte~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
-Statement [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Removing always clobbered register reg byte a as potential for zp ZP_BYTE:3 [ plus::a#0 ]
 Removing always clobbered register reg byte x as potential for zp ZP_BYTE:3 [ plus::a#0 ]
 Statement [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (byte) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte x 
 Statement [5] callprepare plus (byte) '0' (byte) 7  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (byte~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
-Statement [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Statement [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (byte) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte x 
 Potential registers zp ZP_BYTE:2 [ main::$0 ] : zp ZP_BYTE:2 , reg byte a , reg byte x , reg byte y , 
 Potential registers zp ZP_BYTE:3 [ plus::a#0 ] : zp ZP_BYTE:3 , reg byte y , 
 Potential registers zp ZP_BYTE:4 [ plus::b#0 ] : zp ZP_BYTE:4 , reg byte a , reg byte x , reg byte y , 
@@ -261,11 +267,11 @@ Uplift Scope [plus] 4: zp ZP_BYTE:4 [ plus::b#0 ] 2: zp ZP_BYTE:3 [ plus::a#0 ]
 Uplift Scope [main] 2: zp ZP_BYTE:2 [ main::$0 ] 
 Uplift Scope [] 
 
-Uplifting [plus] best 84 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:3 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
-Uplifting [main] best 78 combination reg byte a [ main::$0 ] 
-Uplifting [] best 78 combination 
+Uplifting [plus] best 91 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:3 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
+Uplifting [main] best 85 combination reg byte a [ main::$0 ] 
+Uplifting [] best 85 combination 
 Attempting to uplift remaining variables inzp ZP_BYTE:3 [ plus::a#0 ]
-Uplifting [plus] best 78 combination zp ZP_BYTE:3 [ plus::a#0 ] 
+Uplifting [plus] best 85 combination zp ZP_BYTE:3 [ plus::a#0 ] 
 Allocated (was zp ZP_BYTE:3) zp ZP_BYTE:2 [ plus::a#0 ]
 
 ASSEMBLER BEFORE OPTIMIZATION
@@ -325,11 +331,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 -- vbuaa=vbuz1_plus_vbuaa 
@@ -339,6 +345,9 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -392,7 +401,7 @@ reg byte a [ plus::return#0 ]
 
 
 FINAL ASSEMBLER
-Score: 60
+Score: 67
 
   // File Comments
 // Test a procedure with calling convention stack
@@ -442,11 +451,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // return a+b;
@@ -456,6 +465,9 @@ plus: {
     // plus::@return
     // }
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
diff --git a/src/test/ref/procedure-callingconvention-stack-1.asm b/src/test/ref/procedure-callingconvention-stack-1.asm
index b061638cc..3293ed5f3 100644
--- a/src/test/ref/procedure-callingconvention-stack-1.asm
+++ b/src/test/ref/procedure-callingconvention-stack-1.asm
@@ -27,5 +27,7 @@ plus: {
     lda STACK_BASE+OFFSET_STACK_B,x
     clc
     adc.z a
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
diff --git a/src/test/ref/procedure-callingconvention-stack-1.cfg b/src/test/ref/procedure-callingconvention-stack-1.cfg
index 7d27d5cc1..37c87d1a7 100644
--- a/src/test/ref/procedure-callingconvention-stack-1.cfg
+++ b/src/test/ref/procedure-callingconvention-stack-1.cfg
@@ -22,8 +22,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
diff --git a/src/test/ref/procedure-callingconvention-stack-1.log b/src/test/ref/procedure-callingconvention-stack-1.log
index 121a292ec..9f72690c7 100644
--- a/src/test/ref/procedure-callingconvention-stack-1.log
+++ b/src/test/ref/procedure-callingconvention-stack-1.log
@@ -90,8 +90,8 @@ Adding NOP phi() at start of @1
 Adding NOP phi() at start of @end
 Adding NOP phi() at start of main
 Calling convention STACK_CALL adding prepare/execute/finalize for [5] (byte~) main::$0 ← call plus (byte) '0' (byte) 7 
-Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,plus::OFFSET_STACK_A)
-Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,plus::OFFSET_STACK_B)
+Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,(const byte) plus::OFFSET_STACK_B)
 
 FINAL CONTROL FLOW GRAPH
 @begin: scope:[]  from
@@ -118,8 +118,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
@@ -217,11 +217,11 @@ plus: {
     .label a = 3
     .label b = 4
     .label return = 5
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -234,6 +234,10 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuz1 
+    lda.z return
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -241,16 +245,18 @@ plus: {
 REGISTER UPLIFT POTENTIAL REGISTERS
 Statement [5] callprepare plus (byte) '0' (byte) 7  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (byte~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
-Statement [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Removing always clobbered register reg byte a as potential for zp ZP_BYTE:3 [ plus::a#0 ]
 Removing always clobbered register reg byte x as potential for zp ZP_BYTE:3 [ plus::a#0 ]
 Statement [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (byte) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte x 
 Statement [5] callprepare plus (byte) '0' (byte) 7  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (byte~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
-Statement [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Statement [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (byte) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte x 
 Potential registers zp ZP_BYTE:2 [ main::$0 ] : zp ZP_BYTE:2 , reg byte a , reg byte x , reg byte y , 
 Potential registers zp ZP_BYTE:3 [ plus::a#0 ] : zp ZP_BYTE:3 , reg byte y , 
 Potential registers zp ZP_BYTE:4 [ plus::b#0 ] : zp ZP_BYTE:4 , reg byte a , reg byte x , reg byte y , 
@@ -261,11 +267,11 @@ Uplift Scope [plus] 4: zp ZP_BYTE:4 [ plus::b#0 ] 2: zp ZP_BYTE:3 [ plus::a#0 ]
 Uplift Scope [main] 2: zp ZP_BYTE:2 [ main::$0 ] 
 Uplift Scope [] 
 
-Uplifting [plus] best 84 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:3 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
-Uplifting [main] best 78 combination reg byte a [ main::$0 ] 
-Uplifting [] best 78 combination 
+Uplifting [plus] best 91 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:3 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
+Uplifting [main] best 85 combination reg byte a [ main::$0 ] 
+Uplifting [] best 85 combination 
 Attempting to uplift remaining variables inzp ZP_BYTE:3 [ plus::a#0 ]
-Uplifting [plus] best 78 combination zp ZP_BYTE:3 [ plus::a#0 ] 
+Uplifting [plus] best 85 combination zp ZP_BYTE:3 [ plus::a#0 ] 
 Allocated (was zp ZP_BYTE:3) zp ZP_BYTE:2 [ plus::a#0 ]
 
 ASSEMBLER BEFORE OPTIMIZATION
@@ -325,11 +331,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // [12] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 -- vbuaa=vbuz1_plus_vbuaa 
@@ -339,6 +345,9 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -392,7 +401,7 @@ reg byte a [ plus::return#0 ]
 
 
 FINAL ASSEMBLER
-Score: 60
+Score: 67
 
   // File Comments
 // Test a procedure with calling convention stack
@@ -442,11 +451,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [10] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [10] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [11] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [11] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // return a+b;
@@ -456,6 +465,9 @@ plus: {
     // plus::@return
     // }
     // [13] return (byte) plus::return#0
+    // [13] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
diff --git a/src/test/ref/procedure-callingconvention-stack-2.asm b/src/test/ref/procedure-callingconvention-stack-2.asm
index 74df8cdfc..bc3a11172 100644
--- a/src/test/ref/procedure-callingconvention-stack-2.asm
+++ b/src/test/ref/procedure-callingconvention-stack-2.asm
@@ -51,5 +51,10 @@ plus: {
     lda.z return+1
     adc.z b+1
     sta.z return+1
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
diff --git a/src/test/ref/procedure-callingconvention-stack-2.cfg b/src/test/ref/procedure-callingconvention-stack-2.cfg
index f4cad78b9..30a6021e3 100644
--- a/src/test/ref/procedure-callingconvention-stack-2.cfg
+++ b/src/test/ref/procedure-callingconvention-stack-2.cfg
@@ -22,8 +22,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (word()) plus((word) plus::a , (word) plus::b)
 plus: scope:[plus]  from
-  [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A)
-  [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B)
+  [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A)
+  [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B)
   [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
diff --git a/src/test/ref/procedure-callingconvention-stack-2.log b/src/test/ref/procedure-callingconvention-stack-2.log
index 27c19a06d..4b64e336c 100644
--- a/src/test/ref/procedure-callingconvention-stack-2.log
+++ b/src/test/ref/procedure-callingconvention-stack-2.log
@@ -107,8 +107,8 @@ Adding NOP phi() at start of @1
 Adding NOP phi() at start of @end
 Adding NOP phi() at start of main
 Calling convention STACK_CALL adding prepare/execute/finalize for [5] (word~) main::$0 ← call plus (word) $1234 (word) $2345 
-Calling convention STACK_CALL replacing param((word) plus::a) with paramstack(word,plus::OFFSET_STACK_A)
-Calling convention STACK_CALL replacing param((word) plus::b) with paramstack(word,plus::OFFSET_STACK_B)
+Calling convention STACK_CALL replacing param((word) plus::a) with paramstack(word,(const byte) plus::OFFSET_STACK_A)
+Calling convention STACK_CALL replacing param((word) plus::b) with paramstack(word,(const byte) plus::OFFSET_STACK_B)
 
 FINAL CONTROL FLOW GRAPH
 @begin: scope:[]  from
@@ -135,8 +135,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (word()) plus((word) plus::a , (word) plus::b)
 plus: scope:[plus]  from
-  [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A)
-  [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B)
+  [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A)
+  [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B)
   [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
@@ -243,13 +243,13 @@ plus: {
     .label a = 4
     .label b = 6
     .label return = 8
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -267,6 +267,12 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
@@ -275,9 +281,10 @@ REGISTER UPLIFT POTENTIAL REGISTERS
 Statement [5] callprepare plus (word) $1234 (word) $2345  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (word~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
 Statement [8] *((const word*) SCREEN#0) ← (word~) main::$0 [ ] ( main:2 [ ] ) always clobbers reg byte a 
-Statement [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Statement [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (word) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte a reg byte x 
 Potential registers zp ZP_WORD:2 [ main::$0 ] : zp ZP_WORD:2 , 
 Potential registers zp ZP_WORD:4 [ plus::a#0 ] : zp ZP_WORD:4 , 
 Potential registers zp ZP_WORD:6 [ plus::b#0 ] : zp ZP_WORD:6 , 
@@ -288,9 +295,9 @@ Uplift Scope [plus] 4: zp ZP_WORD:6 [ plus::b#0 ] 2: zp ZP_WORD:4 [ plus::a#0 ]
 Uplift Scope [main] 2: zp ZP_WORD:2 [ main::$0 ] 
 Uplift Scope [] 
 
-Uplifting [plus] best 146 combination zp ZP_WORD:6 [ plus::b#0 ] zp ZP_WORD:4 [ plus::a#0 ] zp ZP_WORD:8 [ plus::return#0 ] 
-Uplifting [main] best 146 combination zp ZP_WORD:2 [ main::$0 ] 
-Uplifting [] best 146 combination 
+Uplifting [plus] best 164 combination zp ZP_WORD:6 [ plus::b#0 ] zp ZP_WORD:4 [ plus::a#0 ] zp ZP_WORD:8 [ plus::return#0 ] 
+Uplifting [main] best 164 combination zp ZP_WORD:2 [ main::$0 ] 
+Uplifting [] best 164 combination 
 Coalescing zero page register [ zp ZP_WORD:4 [ plus::a#0 ] ] with [ zp ZP_WORD:8 [ plus::return#0 ] ] - score: 1
 Coalescing zero page register [ zp ZP_WORD:4 [ plus::a#0 plus::return#0 ] ] with [ zp ZP_WORD:2 [ main::$0 ] ]
 Allocated (was zp ZP_WORD:4) zp ZP_WORD:2 [ plus::a#0 plus::return#0 main::$0 ]
@@ -367,13 +374,13 @@ plus: {
     .label a = 2
     .label b = 4
     .label return = 2
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -391,6 +398,12 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
@@ -442,7 +455,7 @@ zp ZP_WORD:4 [ plus::b#0 ]
 
 
 FINAL ASSEMBLER
-Score: 128
+Score: 146
 
   // File Comments
 // Test a procedure with calling convention stack - and enough parameters to use fast ASM for cleaning stack
@@ -506,13 +519,13 @@ plus: {
     .label a = 2
     .label b = 4
     .label return = 2
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -530,6 +543,12 @@ plus: {
     // plus::@return
     // }
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
diff --git a/src/test/ref/procedure-callingconvention-stack-3.asm b/src/test/ref/procedure-callingconvention-stack-3.asm
index 6c38e74b9..acca2e938 100644
--- a/src/test/ref/procedure-callingconvention-stack-3.asm
+++ b/src/test/ref/procedure-callingconvention-stack-3.asm
@@ -50,5 +50,10 @@ plus: {
     lda.z return+1
     adc.z b+1
     sta.z return+1
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
diff --git a/src/test/ref/procedure-callingconvention-stack-3.cfg b/src/test/ref/procedure-callingconvention-stack-3.cfg
index 26c06ac4c..a6f31f3da 100644
--- a/src/test/ref/procedure-callingconvention-stack-3.cfg
+++ b/src/test/ref/procedure-callingconvention-stack-3.cfg
@@ -22,8 +22,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (word()) plus((word) plus::a , (word) plus::b)
 plus: scope:[plus]  from
-  [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A)
-  [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B)
+  [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A)
+  [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B)
   [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
diff --git a/src/test/ref/procedure-callingconvention-stack-3.log b/src/test/ref/procedure-callingconvention-stack-3.log
index 901fe92d4..0776f09ac 100644
--- a/src/test/ref/procedure-callingconvention-stack-3.log
+++ b/src/test/ref/procedure-callingconvention-stack-3.log
@@ -104,8 +104,8 @@ Adding NOP phi() at start of @1
 Adding NOP phi() at start of @end
 Adding NOP phi() at start of main
 Calling convention STACK_CALL adding prepare/execute/finalize for [5] (word~) main::$0 ← call plus (byte) '0' (byte) 7 
-Calling convention STACK_CALL replacing param((word) plus::a) with paramstack(word,plus::OFFSET_STACK_A)
-Calling convention STACK_CALL replacing param((word) plus::b) with paramstack(word,plus::OFFSET_STACK_B)
+Calling convention STACK_CALL replacing param((word) plus::a) with paramstack(word,(const byte) plus::OFFSET_STACK_A)
+Calling convention STACK_CALL replacing param((word) plus::b) with paramstack(word,(const byte) plus::OFFSET_STACK_B)
 
 FINAL CONTROL FLOW GRAPH
 @begin: scope:[]  from
@@ -132,8 +132,8 @@ main::@return: scope:[main]  from main
 
 __stackcall (word()) plus((word) plus::a , (word) plus::b)
 plus: scope:[plus]  from
-  [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A)
-  [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B)
+  [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A)
+  [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B)
   [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
@@ -239,13 +239,13 @@ plus: {
     .label a = 4
     .label b = 6
     .label return = 8
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -263,6 +263,12 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
@@ -271,9 +277,10 @@ REGISTER UPLIFT POTENTIAL REGISTERS
 Statement [5] callprepare plus (byte) '0' (byte) 7  [ ] ( main:2 [ ] ) always clobbers reg byte a 
 Statement [7] (word~) main::$0 ← callfinalize plus  [ main::$0 ] ( main:2 [ main::$0 ] ) always clobbers reg byte a 
 Statement [8] *((const word*) SCREEN#0) ← (word~) main::$0 [ ] ( main:2 [ ] ) always clobbers reg byte a 
-Statement [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:6 [ plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:6 [ plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Statement [12] (word) plus::return#0 ← (word) plus::a#0 + (word) plus::b#0 [ plus::return#0 ] ( main:2::plus:6 [ plus::return#0 ] ) always clobbers reg byte a 
+Statement [13] return (word) plus::return#0 [ ] ( main:2::plus:6 [ ] ) always clobbers reg byte a reg byte x 
 Potential registers zp ZP_WORD:2 [ main::$0 ] : zp ZP_WORD:2 , 
 Potential registers zp ZP_WORD:4 [ plus::a#0 ] : zp ZP_WORD:4 , 
 Potential registers zp ZP_WORD:6 [ plus::b#0 ] : zp ZP_WORD:6 , 
@@ -284,9 +291,9 @@ Uplift Scope [plus] 4: zp ZP_WORD:6 [ plus::b#0 ] 2: zp ZP_WORD:4 [ plus::a#0 ]
 Uplift Scope [main] 2: zp ZP_WORD:2 [ main::$0 ] 
 Uplift Scope [] 
 
-Uplifting [plus] best 136 combination zp ZP_WORD:6 [ plus::b#0 ] zp ZP_WORD:4 [ plus::a#0 ] zp ZP_WORD:8 [ plus::return#0 ] 
-Uplifting [main] best 136 combination zp ZP_WORD:2 [ main::$0 ] 
-Uplifting [] best 136 combination 
+Uplifting [plus] best 154 combination zp ZP_WORD:6 [ plus::b#0 ] zp ZP_WORD:4 [ plus::a#0 ] zp ZP_WORD:8 [ plus::return#0 ] 
+Uplifting [main] best 154 combination zp ZP_WORD:2 [ main::$0 ] 
+Uplifting [] best 154 combination 
 Coalescing zero page register [ zp ZP_WORD:4 [ plus::a#0 ] ] with [ zp ZP_WORD:8 [ plus::return#0 ] ] - score: 1
 Coalescing zero page register [ zp ZP_WORD:4 [ plus::a#0 plus::return#0 ] ] with [ zp ZP_WORD:2 [ main::$0 ] ]
 Allocated (was zp ZP_WORD:4) zp ZP_WORD:2 [ plus::a#0 plus::return#0 main::$0 ]
@@ -362,13 +369,13 @@ plus: {
     .label a = 2
     .label b = 4
     .label return = 2
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -386,6 +393,12 @@ plus: {
     // plus::@return
   breturn:
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
@@ -437,7 +450,7 @@ zp ZP_WORD:4 [ plus::b#0 ]
 
 
 FINAL ASSEMBLER
-Score: 118
+Score: 136
 
   // File Comments
 // Test a procedure with calling convention stack
@@ -500,13 +513,13 @@ plus: {
     .label a = 2
     .label b = 4
     .label return = 2
-    // [10] (word) plus::a#0 ← paramstack(word,plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
+    // [10] (word) plus::a#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_A) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
     lda STACK_BASE+OFFSET_STACK_A+1,x
     sta.z a+1
-    // [11] (word) plus::b#0 ← paramstack(word,plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
+    // [11] (word) plus::b#0 ← paramstack(word,(const byte) plus::OFFSET_STACK_B) -- vwuz1=_stackgetword_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -524,6 +537,12 @@ plus: {
     // plus::@return
     // }
     // [13] return (word) plus::return#0
+    // [13] return (word) plus::return#0 -- _stackgetword_vbuc1=vwuz1 
+    tsx
+    lda.z return
+    sta STACK_BASE+2,x
+    lda.z return+1
+    sta STACK_BASE+2+1,x
     rts
 }
   // File Data
diff --git a/src/test/ref/procedure-callingconvention-stack-4.asm b/src/test/ref/procedure-callingconvention-stack-4.asm
index cc0338948..f5759ae04 100644
--- a/src/test/ref/procedure-callingconvention-stack-4.asm
+++ b/src/test/ref/procedure-callingconvention-stack-4.asm
@@ -39,5 +39,7 @@ plus: {
     lda STACK_BASE+OFFSET_STACK_B,x
     clc
     adc.z a
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
diff --git a/src/test/ref/procedure-callingconvention-stack-4.cfg b/src/test/ref/procedure-callingconvention-stack-4.cfg
index be222f493..2ab0e12ea 100644
--- a/src/test/ref/procedure-callingconvention-stack-4.cfg
+++ b/src/test/ref/procedure-callingconvention-stack-4.cfg
@@ -29,8 +29,8 @@ main::@return: scope:[main]  from main::@1
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [17] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
diff --git a/src/test/ref/procedure-callingconvention-stack-4.log b/src/test/ref/procedure-callingconvention-stack-4.log
index 3cb2fd89f..c74350be4 100644
--- a/src/test/ref/procedure-callingconvention-stack-4.log
+++ b/src/test/ref/procedure-callingconvention-stack-4.log
@@ -170,8 +170,8 @@ Adding NOP phi() at start of @1
 Adding NOP phi() at start of @end
 Adding NOP phi() at start of main
 Calling convention STACK_CALL adding prepare/execute/finalize for [7] (byte) main::w#0 ← call plus (byte) '0' (byte) main::v#0 
-Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,plus::OFFSET_STACK_A)
-Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,plus::OFFSET_STACK_B)
+Calling convention STACK_CALL replacing param((byte) plus::a) with paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+Calling convention STACK_CALL replacing param((byte) plus::b) with paramstack(byte,(const byte) plus::OFFSET_STACK_B)
 
 FINAL CONTROL FLOW GRAPH
 @begin: scope:[]  from
@@ -205,8 +205,8 @@ main::@return: scope:[main]  from main::@1
 
 __stackcall (byte()) plus((byte) plus::a , (byte) plus::b)
 plus: scope:[plus]  from
-  [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A)
-  [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B)
+  [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A)
+  [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B)
   [17] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0
   to:plus::@return
 plus::@return: scope:[plus]  from plus
@@ -352,11 +352,11 @@ plus: {
     .label a = 6
     .label b = 7
     .label return = 8
-    // [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
+    // [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     sta.z b
@@ -369,6 +369,10 @@ plus: {
     // plus::@return
   breturn:
     // [18] return (byte) plus::return#0
+    // [18] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuz1 
+    lda.z return
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -378,18 +382,20 @@ Statement [7] callprepare plus (byte) '0' (byte) main::v#0  [ main::a#2 ] ( main
 Removing always clobbered register reg byte a as potential for zp ZP_BYTE:2 [ main::a#2 main::a#1 ]
 Statement [9] (byte) main::w#0 ← callfinalize plus  [ main::a#2 main::w#0 ] ( main:2 [ main::a#2 main::w#0 ] ) always clobbers reg byte a 
 Statement [10] (byte~) main::$2 ← (byte) main::w#0 + (byte) main::a#2 [ main::a#2 main::$2 ] ( main:2 [ main::a#2 main::$2 ] ) always clobbers reg byte a 
-Statement [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 ] ) always clobbers reg byte a reg byte x 
 Removing always clobbered register reg byte x as potential for zp ZP_BYTE:2 [ main::a#2 main::a#1 ]
-Statement [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Removing always clobbered register reg byte a as potential for zp ZP_BYTE:6 [ plus::a#0 ]
 Removing always clobbered register reg byte x as potential for zp ZP_BYTE:6 [ plus::a#0 ]
 Statement [17] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:8 [ main::a#2 plus::return#0 ] ) always clobbers reg byte a 
+Statement [18] return (byte) plus::return#0 [ ] ( main:2::plus:8 [ main::a#2 ] ) always clobbers reg byte x 
 Statement [7] callprepare plus (byte) '0' (byte) main::v#0  [ main::a#2 ] ( main:2 [ main::a#2 ] ) always clobbers reg byte a 
 Statement [9] (byte) main::w#0 ← callfinalize plus  [ main::a#2 main::w#0 ] ( main:2 [ main::a#2 main::w#0 ] ) always clobbers reg byte a 
 Statement [10] (byte~) main::$2 ← (byte) main::w#0 + (byte) main::a#2 [ main::a#2 main::$2 ] ( main:2 [ main::a#2 main::$2 ] ) always clobbers reg byte a 
-Statement [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 ] ) always clobbers reg byte a reg byte x 
-Statement [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
+Statement [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) [ plus::a#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 ] ) always clobbers reg byte a reg byte x 
+Statement [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) [ plus::a#0 plus::b#0 ] ( main:2::plus:8 [ main::a#2 plus::a#0 plus::b#0 ] ) always clobbers reg byte a reg byte x 
 Statement [17] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 [ plus::return#0 ] ( main:2::plus:8 [ main::a#2 plus::return#0 ] ) always clobbers reg byte a 
+Statement [18] return (byte) plus::return#0 [ ] ( main:2::plus:8 [ main::a#2 ] ) always clobbers reg byte x 
 Potential registers zp ZP_BYTE:2 [ main::a#2 main::a#1 ] : zp ZP_BYTE:2 , reg byte y , 
 Potential registers zp ZP_BYTE:3 [ main::v#0 ] : zp ZP_BYTE:3 , reg byte a , reg byte x , reg byte y , 
 Potential registers zp ZP_BYTE:4 [ main::w#0 ] : zp ZP_BYTE:4 , reg byte a , reg byte x , reg byte y , 
@@ -403,12 +409,12 @@ Uplift Scope [main] 22.79: zp ZP_BYTE:2 [ main::a#2 main::a#1 ] 22: zp ZP_BYTE:5
 Uplift Scope [plus] 4: zp ZP_BYTE:7 [ plus::b#0 ] 2: zp ZP_BYTE:6 [ plus::a#0 ] 2: zp ZP_BYTE:8 [ plus::return#0 ] 
 Uplift Scope [] 
 
-Uplifting [main] best 651 combination reg byte y [ main::a#2 main::a#1 ] reg byte a [ main::$2 ] reg byte x [ main::v#0 ] reg byte a [ main::w#0 ] 
+Uplifting [main] best 661 combination reg byte y [ main::a#2 main::a#1 ] reg byte a [ main::$2 ] reg byte x [ main::v#0 ] reg byte a [ main::w#0 ] 
 Limited combination testing to 100 combinations of 128 possible.
-Uplifting [plus] best 642 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:6 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
-Uplifting [] best 642 combination 
+Uplifting [plus] best 649 combination reg byte a [ plus::b#0 ] zp ZP_BYTE:6 [ plus::a#0 ] reg byte a [ plus::return#0 ] 
+Uplifting [] best 649 combination 
 Attempting to uplift remaining variables inzp ZP_BYTE:6 [ plus::a#0 ]
-Uplifting [plus] best 642 combination zp ZP_BYTE:6 [ plus::a#0 ] 
+Uplifting [plus] best 649 combination zp ZP_BYTE:6 [ plus::a#0 ] 
 Allocated (was zp ZP_BYTE:6) zp ZP_BYTE:2 [ plus::a#0 ]
 
 ASSEMBLER BEFORE OPTIMIZATION
@@ -493,11 +499,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // [17] (byte) plus::return#0 ← (byte) plus::a#0 + (byte) plus::b#0 -- vbuaa=vbuz1_plus_vbuaa 
@@ -507,6 +513,9 @@ plus: {
     // plus::@return
   breturn:
     // [18] return (byte) plus::return#0
+    // [18] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data
@@ -578,7 +587,7 @@ reg byte a [ plus::return#0 ]
 
 
 FINAL ASSEMBLER
-Score: 537
+Score: 544
 
   // File Comments
 // Test a procedure with calling convention stack
@@ -652,11 +661,11 @@ plus: {
     .const OFFSET_STACK_A = 0
     .const OFFSET_STACK_B = 1
     .label a = 2
-    // [15] (byte) plus::a#0 ← paramstack(byte,plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
+    // [15] (byte) plus::a#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_A) -- vbuz1=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_A,x
     sta.z a
-    // [16] (byte) plus::b#0 ← paramstack(byte,plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
+    // [16] (byte) plus::b#0 ← paramstack(byte,(const byte) plus::OFFSET_STACK_B) -- vbuaa=_stackgetbyte_vbuc1 
     tsx
     lda STACK_BASE+OFFSET_STACK_B,x
     // return a+b;
@@ -666,6 +675,9 @@ plus: {
     // plus::@return
     // }
     // [18] return (byte) plus::return#0
+    // [18] return (byte) plus::return#0 -- _stackgetbyte_vbuc1=vbuaa 
+    tsx
+    sta STACK_BASE+1,x
     rts
 }
   // File Data