Qsys

I am trying to connect PCIe BAR 0 to direct window bridge in qsys. However, i don't really understand how qsys calculate the end address one of the avalon slave cntl (direct window bridge).

In the attachment(qsys.jpeg), it shows that it is from 0x00040000 to 0x00040007. I thought it should be 0x00040000 to 0x00040003. Direct window bridge source file (.sv actually) is attached for reference. Pls advice.

Thanks