Some types of processors, such as the MIPS, PowerPC, and Renesas SH, offer the ability to run either big-endian or little-endian byte orders. Usually the executable or symbol will include a bit to designate the endian-ness, and you will not need to worry about which to use. However, you may still find it useful to adjust gdb's idea of processor endian-ness manually.
set endian big
set endian little
set endian auto
Note that these commands merely adjust interpretation of symbolic data on the host, and that they have absolutely no effect on the target system.