diff --git a/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt b/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
index fe4efc190..bb1c01eba 100644
--- a/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
+++ b/codeOptimizers/src/prog8/optimizer/ExpressionSimplifier.kt
@@ -378,30 +378,44 @@ class ExpressionSimplifier(private val program: Program, private val errors: IEr
 
         if (rightVal!=null && (expr.operator == "==" || expr.operator == "!=")) {
             val bitwise = expr.left as? BinaryExpression
-            if(bitwise!=null && bitwise.operator=="&" && bitwise.inferType(program).isWords) {
-                val andNum = (bitwise.right as? NumericLiteral)?.number?.toInt()
-                if (andNum!=null) {
-                    if ((andNum and 0x00ff) == 0) {
-                        // (WORD & $xx00)==y  ->  (msb(WORD) & $xx)==y
-                        val msb = FunctionCallExpression(IdentifierReference(listOf("msb"), bitwise.left.position), mutableListOf(bitwise.left), bitwise.left.position)
-                        val bytevalue = NumericLiteral(BaseDataType.UBYTE, (andNum shr 8).toDouble(), bitwise.right.position)
-                        val rightvalByte = NumericLiteral(BaseDataType.UBYTE, (rightVal.number.toInt() shr 8).toDouble(), rightVal.position)
-                        return listOf(
-                            IAstModification.ReplaceNode(bitwise.left, msb, bitwise),
-                            IAstModification.ReplaceNode(bitwise.right, bytevalue, bitwise),
-                            IAstModification.ReplaceNode(expr.right, rightvalByte, expr)
-                        )
+            if (bitwise!=null && bitwise.operator=="&") {
+
+                if(rightVal.number in powersOfTwoFloat && bitwise.right.constValue(program) == rightVal) {
+                    if(expr.operator=="==") {
+                        //  x & const == const   ->  x & const != 0   (if const has only a single bit set!)
+                        val notZero = BinaryExpression(bitwise, "!=", NumericLiteral(rightDt.base, 0.0, rightVal.position), expr.position)
+                        return listOf(IAstModification.ReplaceNode(expr, notZero, parent))
+                    } else  {
+                        //  x & const != const   ->  x & const == 0   (if const has only a single bit set!)
+                        val equalsZero = BinaryExpression(bitwise, "==", NumericLiteral(rightDt.base, 0.0, rightVal.position), expr.position)
+                        return listOf(IAstModification.ReplaceNode(expr, equalsZero, parent))
                     }
-                    else if((andNum and 0xff00) == 0) {
-                        // (WORD & $00xx)==y  ->  (lsb(WORD) & $xx)==y
-                        val lsb = FunctionCallExpression(IdentifierReference(listOf("lsb"), bitwise.left.position), mutableListOf(bitwise.left), bitwise.left.position)
-                        val bytevalue = NumericLiteral(BaseDataType.UBYTE, andNum.toDouble(), bitwise.right.position)
-                        val rightvalByte = NumericLiteral(BaseDataType.UBYTE, (rightVal.number.toInt() and 255).toDouble(), rightVal.position)
-                        return listOf(
-                            IAstModification.ReplaceNode(bitwise.left, lsb, bitwise),
-                            IAstModification.ReplaceNode(bitwise.right, bytevalue, bitwise),
-                            IAstModification.ReplaceNode(expr.right, rightvalByte, expr)
-                        )
+                }
+
+                if (bitwise.inferType(program).isWords) {
+                    val andNum = (bitwise.right as? NumericLiteral)?.number?.toInt()
+                    if (andNum!=null) {
+                        if ((andNum and 0x00ff) == 0) {
+                            // (WORD & $xx00)==y  ->  (msb(WORD) & $xx)==y
+                            val msb = FunctionCallExpression(IdentifierReference(listOf("msb"), bitwise.left.position), mutableListOf(bitwise.left), bitwise.left.position)
+                            val bytevalue = NumericLiteral(BaseDataType.UBYTE, (andNum shr 8).toDouble(), bitwise.right.position)
+                            val rightvalByte = NumericLiteral(BaseDataType.UBYTE, (rightVal.number.toInt() shr 8).toDouble(), rightVal.position)
+                            return listOf(
+                                IAstModification.ReplaceNode(bitwise.left, msb, bitwise),
+                                IAstModification.ReplaceNode(bitwise.right, bytevalue, bitwise),
+                                IAstModification.ReplaceNode(expr.right, rightvalByte, expr)
+                            )
+                        } else if((andNum and 0xff00) == 0) {
+                            // (WORD & $00xx)==y  ->  (lsb(WORD) & $xx)==y
+                            val lsb = FunctionCallExpression(IdentifierReference(listOf("lsb"), bitwise.left.position), mutableListOf(bitwise.left), bitwise.left.position)
+                            val bytevalue = NumericLiteral(BaseDataType.UBYTE, andNum.toDouble(), bitwise.right.position)
+                            val rightvalByte = NumericLiteral(BaseDataType.UBYTE, (rightVal.number.toInt() and 255).toDouble(), rightVal.position)
+                            return listOf(
+                                IAstModification.ReplaceNode(bitwise.left, lsb, bitwise),
+                                IAstModification.ReplaceNode(bitwise.right, bytevalue, bitwise),
+                                IAstModification.ReplaceNode(expr.right, rightvalByte, expr)
+                            )
+                        }
                     }
                 }
             }
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index bfc8fa256..29eb70191 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -4,13 +4,11 @@ TODO
 Halloween is stuck on a black screen
 
 
-Optimize bitwise operations on word values where only the msb or lsb is touched:  (already done for simple expressions!)
+Optimize 6502 bitwise operations on word values where only the msb or lsb is touched:  (already done for simple augmented expressions!)
         cx16.r0 = (cx16.r0 & $a000) | $0055
         cx16.r0 = (cx16.r0 | $a000) ^ $0055
         cx16.r0 = (cx16.r0 ^ $a000) & $0055
 
-Optimize (x & y) == y expressions especially in loop conditions
-
 
 update zsmkit to newest version that includes the on_deck routines when stabilized
 
diff --git a/examples/test.p8 b/examples/test.p8
index 858091579..dec36ba29 100644
--- a/examples/test.p8
+++ b/examples/test.p8
@@ -1,68 +1,69 @@
+%import textio
 %zeropage basicsafe
 %option no_sysinit
 
 main {
     sub start() {
 
-        while cx16.r0L & 1 == 0 {
+        cx16.r0L = %11111110
+        while cx16.r0L &32 == 32 {
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
         }
+        txt.nl()
 
-        while cx16.r0L & 1 == 1 {
+        cx16.r0L = %11111110
+        while cx16.r0L &32 != 0 {
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
         }
+        txt.nl()
 
-        while cx16.r0L & 64 == 0 {
-        }
-
-        while cx16.r0L & 64 == 64 {
-        }
-
-        do { }
-        until cx16.r0L & 1 == 0
-
-        do { }
-        until cx16.r0L & 1 == 1
-
-        do { }
-        until cx16.r0L & 64 == 0
-
-        do { }
-        until cx16.r0L & 64 == 64
-
-        while cx16.r0L & 1 == 0 {
-            cx16.r0L++
-        }
-
-        while cx16.r0L & 1 == 1 {
-            cx16.r0L++
-        }
-
-        while cx16.r0L & 64 == 0 {
-            cx16.r0L++
-        }
-
-        while cx16.r0L & 64 == 64 {
-            cx16.r0L++
+        ; this one must not be changed and stop after 3 iterations instead of 5!
+        cx16.r0L = %11111110
+        while cx16.r0L &40 == 40 {
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
         }
+        txt.nl()
+        txt.nl()
 
+        cx16.r0L = %11111110
         do {
-            cx16.r0L++
-        }
-        until cx16.r0L & 1 == 0
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
+        } until cx16.r0L &32 != 32
+        txt.nl()
 
+        cx16.r0L = %11111110
         do {
-            cx16.r0L++
-        }
-        until cx16.r0L & 1 == 1
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
+        } until cx16.r0L &32 == 0
+        txt.nl()
 
+        ; this one must not be changed and stop after 3 iterations instead of 5!
+        cx16.r0L = %11111110
         do {
-            cx16.r0L++
-        }
-        until cx16.r0L & 64 == 0
+            cx16.r0L <<= 1
+            txt.print_ubbin(cx16.r0L, true)
+            txt.nl()
+        } until cx16.r0L &40 != 40
+        txt.nl()
 
-        do {
-            cx16.r0L++
-        }
-        until cx16.r0L & 64 == 64
+
+;        while cx16.r0L & cx16.r1L == 0 {
+;            cx16.r0L++
+;        }
+;
+;        while cx16.r0L & cx16.r1L == cx16.r1L {
+;            cx16.r0L++
+;        }
 
 /*
         sys.set_irqd()