Hi David, On Wed, Jun 13, 2012 at 2:49 PM, David Naylor <naylor.b.david at gmail.com> wrote: > [translation:ERROR] assert instr_list is not None, 'Unknown opcode: %s ' % op > [translation:ERROR] AssertionError: Unknown opcode: v2539 = jit_is_virtual(vref_0) Try again? Armin