SHADOW_AUD_VOL_CTL
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, (old & ~0x3f) | v);
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, vol);
volume = cx_sread(SHADOW_AUD_VOL_CTL);
cx_swrite(SHADOW_AUD_VOL_CTL, AUD_VOL_CTL, volume);
cx_read(AUD_CTL), cx_sread(SHADOW_AUD_VOL_CTL));
.sreg = SHADOW_AUD_VOL_CTL,
.sreg = SHADOW_AUD_VOL_CTL,