> Why have an intermediate copy when that's not necessary at all? It > seems like pure overhead to be. > > Furthermore, cpu's have byte-shifting load and store instructions > which will be used if you make use of the 'p' versions of the endian > swap functions, such as cpu_to_le16p(). > > So it's going to cost basically nothing.
I didn't mean the runtime cost of any conversion that might happen, I was thinking about how much these conversions would affect the code that uses these header structs. While for the u16/u32 fields this might be not much, it will be more for the hardware address fields since these are stored as the little endian encoding of u64 field you get when reading the u8[8] as a __be64. If I understand you correctly, these fields would also have to be in network byte order in the header struct, introducing copy-and-swaps in every upper layer that uses those addresses and making address matching harder since memcmp won't work anymore. What would be better here? Explicit endianness on all fields for consistency and thus __le64 for EUI64 members with copy-swap functions to convert those addresses into u8[8] where required, explicit endianness on everything except addresses, or keeping it as is? I'm honestly not sure. I want to note here that struct ieee802154_addr, which holds the address information and is also used by BSD socket calls, has always used host byte order for its own fields. This might itself be a huge mistake, but it is relevant to this discussion. ------------------------------------------------------------------------------ Subversion Kills Productivity. Get off Subversion & Make the Move to Perforce. With Perforce, you get hassle-free workflows. Merge that actually works. Faster operations. Version large binaries. Built-in WAN optimization and the freedom to use Git, Perforce or both. Make the move to Perforce. http://pubads.g.doubleclick.net/gampad/clk?id=122218951&iu=/4140/ostg.clktrk _______________________________________________ Linux-zigbee-devel mailing list Linux-zigbee-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-zigbee-devel
