touchups

Author: ggreif

src/Wasm/Exec/Eval.hs

@@ -488,11 +488,10 @@ step(Code cs cfg vs (e:es)) = (`runReaderT` cfg) $ do
             Right () -> k vs' es
             Left exn -> k vs' (Trapping (memoryErrorString exn) @@ at : es)
 
-        (MemoryCopy, I32 cnt : I32 src : I32 dst : vs') -> {-# SCC step_MemoryFill #-} do
+        (MemoryCopy, I32 cnt : I32 src : I32 dst : vs') -> {-# SCC step_MemoryCopy #-} do
           inst    <- getFrameInst
           mem     <- lift $ memory inst (0 @@ at)
-          let addr_dst = fromIntegral $ i64_extend_u_i32 (fromIntegral dst)
-          let addr_src = fromIntegral $ i64_extend_u_i32 (fromIntegral src)
+          let [addr_dst, addr_src] = fromIntegral . i64_extend_u_i32 . fromIntegral <*> [dst, src]
           eres <- lift $ lift $ runExceptT $
             mapM_ (\off -> Memory.loadPacked Pack8 ZX mem addr_src off I32Type >>= Memory.storePacked Pack8 mem addr_dst off) [0 .. pred cnt]
           case eres of