INTEGER southCommMode
southCommMode = _tileCommModeS(bi,bj)
IF ( southCommMode .EQ. COMM_MSG ) THEN
ELSEIF ( southCommMode .EQ. COMM_PUT ) THEN
ELSEIF ( southCommMode .NE. COMM_NONE
& .AND. southCommMode .NE. COMM_GET ) THEN
southCommMode = _tileCommModeE(bi,bj)
IF ( southCommMode .EQ. COMM_PUT ) northRecvAck(1,biS,bjS) = 1.
IF ( southCommMode .EQ. COMM_GET ) northRecvAck(1,biS,bjS) = 1.
IF ( southCommMode .EQ. COMM_GET ) THEN