frac32 in1
frac32 out
frac32 D
frac32 S
if (inlet_AD < (32 << 21)) {
  // AR mode
  // A long -> A short
  outlet_A = 0x07FFFFFF - (inlet_AD << 1);
  outlet_D = 0x07FFFFFF;
  outlet_S = 0x07FFFFFF;
} else {
  // DR mode
  outlet_A = 0;
  // D long -> D short
  outlet_D = 0x0FFFFFFF - (inlet_AD << 1);
  outlet_S = 0;
}