OPL3_TOTAL_LEVEL_MASK
oldvol = OPL3_TOTAL_LEVEL_MASK - (*volbyte & OPL3_TOTAL_LEVEL_MASK);
if (newvol > OPL3_TOTAL_LEVEL_MASK)
newvol = OPL3_TOTAL_LEVEL_MASK;
n = OPL3_TOTAL_LEVEL_MASK - (newvol & OPL3_TOTAL_LEVEL_MASK);
*volbyte = (*volbyte & OPL3_KSL_MASK) | (n & OPL3_TOTAL_LEVEL_MASK);
opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 1 volume */
opl3->command(opl3, opl3_reg, OPL3_TOTAL_LEVEL_MASK); /* Operator 2 volume */
reg_val |= ~voice->volume & OPL3_TOTAL_LEVEL_MASK;