Weddington, Eric wrote: > >> >>> Section 20.13.7 of the Xmega manual speaks about the requirement of 16 >>> bit alignment. >>> >>> http://www.atmel.com/images/doc8331.pdf >>> >>> As the MAXIMUM_ALIGNMENT in avr.h is set to 1, it throws an error when >>> trying to compile. >>> >>> I have attached a patch which sets it to 2 by default in the compiler. I >>> have also attached a case which fails. >>> >>> Would this be an acceptable change ? >> Hi George, >> >> No, this would not be an acceptable change, because it is changing the >> data alignment for the whole compiler, when there is only a restriction on >> a data structure for a single peripheral for a small subset of the AVR >> processors. >> >> This is why the data attribute "aligned" exists. Just do this for your >> data structure: __attribute__ ((aligned (2))) > > Excuse me, perhaps I have this wrong... (It's still early for me). > > Does changing MAXIMUM_ALIGNMENT allow the aligned attribute to work? If we > don't change MAXIMUM_ALIGNMENT, are you saying that the aligned attribute > fails?
See PR53448. In general, that is no issue in < 4.7 because only xmega needs align(2) and these versions don't support xmega. Besides that, 4.7 had quite some clean-up of w.r.t. ELF, e.g. avr/elf.h. Even if it works with changing MAXIMUM_ALIGNMENT, that's not the purpose of MAXIMUM_ALIGNMENT. Johann _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org https://lists.nongnu.org/mailman/listinfo/avr-gcc-list
