IORD_XDIRECT and IOWR_XDIRECT?

Hello:

I want to ask that the IORD_XDIRECT or IOWR_XDIRECT will affect the byteenable signals?

For example IOWR_16DIRECT ,the byteenable[1..0] will both low; IOWR_8DIRECT only one byteenable signal

will low , others high. I hope somebody can explain.

Best regards

jigdo