diff --git a/compiler/examples/test.p8 b/compiler/examples/test.p8
index 7d88f1510..2d36818c7 100644
--- a/compiler/examples/test.p8
+++ b/compiler/examples/test.p8
@@ -4,12 +4,13 @@
 
 ~ main {
 
-    byte[2] barray = 0
-    byte[2] barray2 =0
+    byte[10,5] barray = 0
 
 sub start() {
-    X=barray[0]
-    return
+    X=barray[2,3]
+    barray[3,3]=X
+
+
 }
 
 
diff --git a/compiler/src/prog8/ast/AstChecker.kt b/compiler/src/prog8/ast/AstChecker.kt
index ce3d4534e..f82b83635 100644
--- a/compiler/src/prog8/ast/AstChecker.kt
+++ b/compiler/src/prog8/ast/AstChecker.kt
@@ -233,8 +233,6 @@ class AstChecker(private val namespace: INameScope,
      * Also check data type compatibility
      */
     override fun process(assignment: Assignment): IStatement {
-        // todo deal with target.arrayindexed
-
         if(assignment.target.identifier!=null) {
             val targetName = assignment.target.identifier!!.nameInSource
             val targetSymbol = namespace.lookup(targetName, assignment)
@@ -273,7 +271,6 @@ class AstChecker(private val namespace: INameScope,
                     else if(assignment.target.identifier!=null)
                         assignment.target.identifier!!
                     else if(assignment.target.arrayindexed!=null) {
-                        // todo deal with target.arrayindexed
                         assignment.target.arrayindexed!!
                     } else throw FatalAstException("strange assignment")
 
@@ -575,7 +572,21 @@ class AstChecker(private val namespace: INameScope,
                 }
             }
         } else if(postIncrDecr.target.arrayindexed!=null) {
-            // todo deal with target.arrayindexed
+            val indexedRegister = postIncrDecr.target.arrayindexed?.register
+            if(indexedRegister!=null) {
+                if(indexedRegister==Register.A || indexedRegister==Register.X || indexedRegister==Register.Y)
+                    checkResult.add(SyntaxError("array indexing on registers requires register pair variable", postIncrDecr.position))
+            } else {
+                val target = postIncrDecr.target.arrayindexed?.identifier?.targetStatement(namespace)
+                if(target==null) {
+                    checkResult.add(SyntaxError("undefined symbol", postIncrDecr.position))
+                }
+                else {
+                    val dt = (target as VarDecl).datatype
+                    if(dt!=DataType.ARRAY && dt!=DataType.ARRAY_W && dt!=DataType.ARRAY_F)
+                        checkResult.add(SyntaxError("can only increment or decrement a byte/float/word", postIncrDecr.position))
+                }
+            }
         }
         return super.process(postIncrDecr)
     }
diff --git a/compiler/src/prog8/compiler/Compiler.kt b/compiler/src/prog8/compiler/Compiler.kt
index 5323f4734..0ded59a61 100644
--- a/compiler/src/prog8/compiler/Compiler.kt
+++ b/compiler/src/prog8/compiler/Compiler.kt
@@ -468,6 +468,7 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram,
             DataType.ARRAY -> Opcode.READ_INDEXED_VAR
             DataType.ARRAY_W -> Opcode.READ_INDEXED_VAR_W
             DataType.ARRAY_F -> Opcode.READ_INDEXED_VAR_F
+            DataType.MATRIX -> Opcode.READ_INDEXED_VAR
             else -> throw CompilerException("invalid dt for indexed $dt")
         }
     }
@@ -477,6 +478,7 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram,
             DataType.ARRAY -> Opcode.WRITE_INDEXED_VAR
             DataType.ARRAY_W -> Opcode.WRITE_INDEXED_VAR_W
             DataType.ARRAY_F -> Opcode.WRITE_INDEXED_VAR_F
+            DataType.MATRIX -> Opcode.WRITE_INDEXED_VAR
             else -> throw CompilerException("invalid dt for indexed $dt")
         }
     }
@@ -1110,10 +1112,18 @@ private class StatementTranslator(private val stackvmProg: StackVmProgram,
             stackvmProg.instr(Opcode.ADD_W)
         }
 
-        if(write)
-            stackvmProg.instr(opcodeWriteindexedvar(variable!!.datatype), callLabel = variableName)
-        else
-            stackvmProg.instr(opcodeReadindexedvar(variable!!.datatype), callLabel = variableName)
+        if(variable!=null) {
+            if (write)
+                stackvmProg.instr(opcodeWriteindexedvar(variable.datatype), callLabel = variableName)
+            else
+                stackvmProg.instr(opcodeReadindexedvar(variable.datatype), callLabel = variableName)
+        } else {
+            // register indexed
+            if (write)
+                stackvmProg.instr(opcodeWriteindexedvar(DataType.ARRAY), callLabel = arrayindexed.register!!.toString())
+            else
+                stackvmProg.instr(opcodeReadindexedvar(DataType.ARRAY), callLabel = arrayindexed.register!!.toString())
+        }
     }
 
     private fun createSyscall(funcname: String) {