Solution:
In case where the write data width is 36 bits and read width is 18 bits.
1. If Big Endian is selected, first bit 35 to bit 18 are read out, then bit 17 to bit 0 are read out.
2. If Little Endian is selected, first bit 17 to bit 0 are read out, then bit 35 to bit 18 are read out.