PSW_MBS
if ((gr[_REG_PSW] & (PSW_MBS|PSW_MBZ)) != PSW_MBS) {
tf->tf_ipsw = PSW_MBS | (hppa_cpu_ispa20_p() ? PSW_O : 0);
uc->uc_mcontext.__gregs[_REG_PSW] &= ~PSW_MBS;