diff --git a/src/errcodes.f90 b/src/errcodes.f90
index d257188..b50c583 100644
--- a/src/errcodes.f90
+++ b/src/errcodes.f90
@@ -12,9 +12,8 @@ contains
     implicit none
 ! arguments
     integer, intent(in) :: ierr
-    integer, intent(out) :: istop
-    
-    if(ibits(ierr,pnpl, lnpl )==2  .or.    & ! N// too large
+    integer, intent(inout) :: istop
+    if(ibits(ierr,pnpl, lnpl )>1  .or.    & ! N// too large
        ibits(ierr,palph,lalph)==1) then      ! alpha < 0
       istop = 1
 !    else