请您解释一下altera lpm_fifo_dc0中 wrusedw和rdusedw信号的含义

SAME QUESTIOIN

# FIFO:  write-port -> (data-in) -> [buffer] -> (data-out) -> read-port
# lpm_fifo_dc: it is dual-clock FIFO, that is, one clock input for read-port,
and another clock input for write-port.
# wrusedw: it shows total used word in FIFO from view point of write-port
# rdusedw: it shows total used word in FIFO from view point of read-port
# So, why it needs two separated "used word" indications for write-port and read-port?
(ANS)
Because there are two seperated clock inputs for write-port and read-port.
These clocks may not be the same (this is the key feature of dual-clock FIFO)
So wrusedw is sync with clock of write-port, rdusedw is sync with clock of read-port.