PSL_Z
{ PSL_Z, "ZF ", "zf "},
#define PSL_USER (PSL_C | PSL_MBO | PSL_PF | PSL_AF | PSL_Z | PSL_N | PSL_V)
#define PSL_MBZ (PSL_Y|PSL_Z|PSL_S|PSL_X|PSL_M|PSL_R)
#define db_clear_single_step(r) ((r)->tf_flags &= ~(PSL_Z))
#define db_set_single_step(r) ((r)->tf_flags |= (PSL_Z))