IBM_EC_MASK_MUTE
val_ec = (arg == 1) ? val_ec | IBM_EC_MASK_MUTE :
val_ec & (~IBM_EC_MASK_MUTE);
val = ((val_ec & IBM_EC_MASK_MUTE) == IBM_EC_MASK_MUTE);
val = ((val_ec & IBM_EC_MASK_MUTE) == IBM_EC_MASK_MUTE);