On Wednesday 12 October 2011 17:23:20 Bernhard Kaindl wrote: > The U-Boot dns command only worked in little-endian CPUs so far because it > was based on an antique version of the TADNS source which was using a > broken macro to read the shorts found in DNS reply messages by shifting > the LSB from the message into the CPU's MSB of a short int and the MSB > from the stream into the LSB part of the CPU's short int. So far, so > twisted. > > To correct the twisted bytes, the code used ntohs() as a byte-swapping > function to swap the MSB back where it belongs and vice versa. > > This works fine, except that ntohs() naturally does nothing on big-endian > CPUs. > > So on big-endian CPUs, the MSB from the message stayed in the LSB of the > CPU and vice versa. > > Ditch this brain-deadness by just shifting the MSB from the network byte > stream of the reply message into the right (MSB) location of a short int > and putting the LSB from the network byte stream as the lower byte of it, > and we are done with reading the short from the network stream for both > endianesses, no ntohs() or such!
please use a standard macro instead of inventing yet another. we've got the rich Linux api which should cover every case you could possibly need. cpu_to_{l,b}e{16,32,64}(...) {l,b}e_to_cpu{16,32,63}(...) see include/linux/byteorder/ -mike
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