[ethmac] Questions

[zou.yixin@zte.com.cn]

hi,
I have a few questions when I am reading the code of ethmac. 
1.        TxStartFrmIn ,from host. When will it be  asserted and deasserted? I think that it is asserted when host has a frame to  send and  sigal TxDone or TxAbort is asserted .After TxStartFrmIn is asserted,it will be deasserted when TxUsedDataOut is set to 1. Right?
2.The statement is from eth_transmitcontrol.v:
 if(WillSendControlFrame & ~TxUsedDataOut & (TxDoneIn | TxAbortIn | TxStartFrmIn | ~TxUsedDataOutDetected))
    TxCtrlStartFrm <= #Tp 1'b1;
Can I remove the signal TxStartFrmIn ? I can not find the time that WillSendControlFrame=1 && TxUsedDateOut=0 && TxUsedDataOutDetected=1 && TxStartFrmIn=1 . 

3.£¨eth_RxControl.v£©
 The module output signal ReceivedPauseFrm.Why not ReceivedPauseFrmWAddr but ReceivedPauseFrm? 
4.(eth_Transmitcontrol.v) 
assign IncrementByteCnt = CtrlMux & (TxCtrlStartFrm & ~TxCtrlStartFrm_q & ~TxUsedDataIn | TxUsedDataIn & ~ControlEnd);
Can I remove  TxCtrlStartFrm & ~TxCtrlStartFrm_q & ~TxUsedDataIn ?Is it necessary?

Thanks,
yxzhou