Am Thu, 23 Jan 2014 11:30:41 +0000 schrieb "Mike" <n...@none.com>:
> > The __asm__ __volatile__ seems to indicate Iain is right. Notice > the message = *.LC1 in the unoptimized version, but not the > optimized version. This is the first time I've seen this kind of > output, so can you decipher what's going on? We can see a few things in that output: * The function really got inlined * The ASM is still there and marked as volatile * In the optimized version, the ubyte[3] message variable is still there, but it's not initialized (message =*.LC1 is pseudo code for 'initialize message on the stack with the data stored at .LC1') > And here's the optimized assembly. I'm not sure how to do this, > so I used -fverbose-asm -Wa,-adhln > ********** > http://pastebin.com/NY2PNWzS > ********** Nice, I always used -S but this output is better of course ;-) I think what could be happening here is that GCC doesn't know what memory you're accessing via the message pointer in SendCommand. See http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html and search for "If your assembler instructions access memory in an unpredictable fashion" Maybe typing "message" as uint* or uint[3]* instead of void* is already good enough. Otherwise try using a memory input as described on that page.
