GUSMASK_VOICE_ROLL
sc->sc_voc[GUS_VOICE_LEFT].volcntl &= ~(GUSMASK_VOICE_ROLL);
sc->sc_voc[GUS_VOICE_LEFT].volcntl &= ~(GUSMASK_VOICE_ROLL);
sc->sc_voc[GUS_VOICE_LEFT].volcntl |= GUSMASK_VOICE_ROLL;
sc->sc_voc[GUS_VOICE_RIGHT].volcntl &= ~(GUSMASK_VOICE_ROLL);
sc->sc_voc[voice].volcntl &= ~GUSMASK_VOICE_ROLL;
sc->sc_voc[voice].volcntl &= ~GUSMASK_VOICE_ROLL;
sc->sc_voc[voice].volcntl |= GUSMASK_VOICE_ROLL;
sc->sc_voc[GUS_VOICE_LEFT].volcntl &= ~GUSMASK_VOICE_ROLL;
sc->sc_voc[GUS_VOICE_LEFT].volcntl |= GUSMASK_VOICE_ROLL;