GUSMASK_VOICE_IRQ
sc->sc_voc[voice].voccntl & ~(GUSMASK_VOICE_IRQ));
sc->sc_voc[voice].voccntl |= GUSMASK_VOICE_IRQ;
sc->sc_voc[voice].voccntl &= ~GUSMASK_VOICE_IRQ;
sc->sc_voc[voice].voccntl &= ~(GUSMASK_VOICE_IRQ);