On Sun, 2015-12-20 at 21:52 +1100, Alex Brown wrote: > Hi, > > Thanks for that. > > I was trying to avoid using a memory barrier (ever time I write non > portable code, I shed a small tear), Well, change the #define memory_barrier to whatever your toolchain supports and make it portable in the build setup :) You can also make all the stores that need to be strictly ordered store to volatile mems (like you did in one of your working examples). However, using volatile alone is sometimes not enough when doing hardware access/communication, because the compiler doesn't know about the side effects of memory mapped IO. > but I am guessing that because I > only access the address of the text variable, rather than the value, > GCC can't know that it needs to fill in the values before the > assignment ? Yes, it only treats that volatile store as volatile. Whether the stored value is an address or not doesn't matter at that point. Cheers, Oleg
