diff --git a/src/JVM/Data/Analyse/StackMap.hs b/src/JVM/Data/Analyse/StackMap.hs
index bf33621..b61c574 100644
--- a/src/JVM/Data/Analyse/StackMap.hs
+++ b/src/JVM/Data/Analyse/StackMap.hs
@@ -86,8 +86,8 @@ analyseBlockDiff current block = foldl' (flip analyseInstruction) current (takeW
         if i > genericLength ba.locals
             then error $ "ILoad index out of bounds. Given: " <> show i <> " Locals: " <> show ba.locals
             else ba{stack = lvToStackEntry (ba.locals !! fromIntegral i) : ba.stack}
-    analyseInstruction (AStore i) ba = ba{locals = replaceAtOrGrow (fromIntegral (i - 1)) (stackEntryToLV $ head ba.stack) ba.locals, stack = tail ba.stack}
-    analyseInstruction (IStore i) ba = ba{locals = replaceAtOrGrow (fromIntegral (i - 1)) (stackEntryToLV $ head ba.stack) ba.locals, stack = tail ba.stack}
+    analyseInstruction (AStore i) ba = ba{locals = replaceAtOrGrow (fromIntegral i) (stackEntryToLV $ head ba.stack) ba.locals, stack = tail ba.stack}
+    analyseInstruction (IStore i) ba = ba{locals = replaceAtOrGrow (fromIntegral i) (stackEntryToLV $ head ba.stack) ba.locals, stack = tail ba.stack}
     analyseInstruction AReturn ba = ba{stack = tail ba.stack}
     analyseInstruction Return ba = ba
     analyseInstruction (LDC (LDCInt _)) ba = ba{stack = StackEntry (PrimitiveFieldType Int) : ba.stack}
diff --git a/test/Analyse.hs b/test/Analyse.hs
index 69e6fa9..288202b 100644
--- a/test/Analyse.hs
+++ b/test/Analyse.hs
@@ -49,6 +49,29 @@ genFieldType =
 spec :: Spec
 spec = describe "Analysis checks" $ do
     describe "Does StackDiff concatenation correctly" $ do
+        it "Can identify incredibly simple blocks properly" $ do
+            let (_, code) = runCodeBuilder $ do
+                    emit $ LDC (LDCInt 0) -- [0]
+                    emit $ AStore 0
+                    emit $ ALoad 0
+                    emit AReturn
+
+            hedgehog $ do
+                let blocks = splitIntoBasicBlocks code
+
+                blocks
+                    === [ BasicBlock 0 [LDC (LDCInt 0), AStore 0, ALoad 0, AReturn] Nothing
+                        ]
+
+                let top = topFrame (MethodDescriptor [] (TypeReturn (PrimitiveFieldType Int)))
+                let nextFrame = analyseBlockDiff top (head blocks)
+
+                nextFrame
+                    === Frame
+                        { locals = [LocalVariable (PrimitiveFieldType Int)]
+                        , stack = []
+                        }
+
         it "Can identify sameframe blocks properly" $ do
             let (l, _, code) = runCodeBuilder' $ do
                     label <- newLabel
@@ -93,24 +116,24 @@ spec = describe "Analysis checks" $ do
             let (l, _, code) = runCodeBuilder' $ do
                     label <- newLabel
                     emit $ LDC (LDCInt 0) -- [0]
-                    emit $ IStore 1 -- []
+                    emit $ IStore 0 -- []
                     emit $ LDC (LDCInt 0) -- [0]
-                    emit $ IStore 2 -- []
-                    emit $ ILoad 1 -- [0]
+                    emit $ IStore 1 -- []
+                    emit $ ILoad 0 -- [0]
                     emit $ IfLe label -- []
                     emit $ LDC (LDCInt 0) -- [0]
-                    emit $ IStore 3 -- []
+                    emit $ IStore 2 -- []
                     emit $ Label label -- []
                     emit $ LDC (LDCInt 0) -- [0]
-                    emit $ IStore 3 -- []
+                    emit $ IStore 2 -- []
                     emit Return -- []
                     pure label
             hedgehog $ do
                 let blocks = splitIntoBasicBlocks code
 
                 blocks
-                    === [ BasicBlock 0 [LDC (LDCInt 0), IStore 1, LDC (LDCInt 0), IStore 2, ILoad 1, IfLe l, LDC (LDCInt 0), IStore 3] (Just l)
-                        , BasicBlock 1 [LDC (LDCInt 0), IStore 3, Return] Nothing
+                    === [ BasicBlock 0 [LDC (LDCInt 0), IStore 0, LDC (LDCInt 0), IStore 1, ILoad 0, IfLe l, LDC (LDCInt 0), IStore 2] (Just l)
+                        , BasicBlock 1 [LDC (LDCInt 0), IStore 2, Return] Nothing
                         ]
 
                 let top = topFrame (MethodDescriptor [] VoidReturn)