diff --git a/pkg/vm/stack.go b/pkg/vm/stack.go
index 62f45022a..1b1130f53 100644
--- a/pkg/vm/stack.go
+++ b/pkg/vm/stack.go
@@ -351,10 +351,11 @@ func (s *Stack) ReverseTop(n int) error {
 		return nil
 	}
 
-	for i, j := 0, n-1; i < j; {
-		s.swap(i, j)
-		i++
-		j--
+	a, b := s.Peek(0), s.Peek(n-1)
+	for i := 0; i < n/2; i++ {
+		a.value, b.value = b.value, a.value
+		a = a.Next()
+		b = b.Prev()
 	}
 	return nil
 }
diff --git a/pkg/vm/vm.go b/pkg/vm/vm.go
index 9d22a96f1..a39c27365 100644
--- a/pkg/vm/vm.go
+++ b/pkg/vm/vm.go
@@ -273,6 +273,7 @@ func (v *VM) LoadScript(b []byte) {
 
 // LoadScriptWithFlags loads script and sets call flag to f.
 func (v *VM) LoadScriptWithFlags(b []byte, f smartcontract.CallFlag) {
+	v.checkInvocationStackSize()
 	ctx := NewContext(b)
 	v.estack = v.newItemStack("estack")
 	ctx.estack = v.estack
@@ -1226,7 +1227,6 @@ func (v *VM) execute(ctx *Context, op opcode.Opcode, parameter []byte) (err erro
 		}
 
 	case opcode.CALL, opcode.CALLL:
-		v.checkInvocationStackSize()
 		// Note: jump offset must be calculated regarding to new context,
 		// but it is cloned and thus has the same script and instruction pointer.
 		v.call(ctx, v.getJumpOffset(ctx, parameter))
@@ -1476,6 +1476,7 @@ func (v *VM) Call(ctx *Context, offset int) {
 // affect the invocation counter and is only being used by vm
 // package.
 func (v *VM) call(ctx *Context, offset int) {
+	v.checkInvocationStackSize()
 	newCtx := ctx.Copy()
 	newCtx.CheckReturn = NoCheck
 	newCtx.local = nil
@@ -1520,7 +1521,8 @@ func (v *VM) calcJumpOffset(ctx *Context, parameter []byte) (int, int, error) {
 
 func (v *VM) handleException() {
 	pop := 0
-	ictx := v.istack.Peek(0).Value().(*Context)
+	ictxv := v.istack.Peek(0)
+	ictx := ictxv.Value().(*Context)
 	for ictx != nil {
 		e := ictx.tryStack.Peek(0)
 		for e != nil {
@@ -1546,7 +1548,8 @@ func (v *VM) handleException() {
 			return
 		}
 		pop++
-		ictx = v.istack.Peek(pop).Value().(*Context)
+		ictxv = ictxv.Next()
+		ictx = ictxv.Value().(*Context)
 	}
 }