Hi, On Tue, Nov 25, 2014 at 8:21 PM, Gedare Bloom <ged...@gwu.edu> wrote:
> I'm pretty sure STACK_ALIGNMENT just does the initial stack align for > the start of the stack. The compiler is responsible for laying out the > frames after that, and for generating aligned entries in the stack > itself. Probably the compiler is being too lax. Check for some > compiler flags for the target that might be used to increase the > alignment, for example if there is a strict alignment flag. Check with > the epiphany / parallela boards too, ask about compiler flags for > alignment problems. > > I checked their GCC port, and I think they define the proper macros for stack alignments to 8 bytes. However, when debugging on real HW (Parallella), I can see that some structures are allocated on non 8-bytes boundaries, and also structures passed as function arguments are not aligned. > -Gedare > > On Tue, Nov 25, 2014 at 2:06 PM, Hesham Moustafa > <heshamelmat...@gmail.com> wrote: > > Hi all, > > > > I came across an issue with alignment when I am porting RTEMS to Epiphany > > now. The reference manual says that stores should be aligned according to > > the store instruction type (half word, word, double word). For example > strd > > instruction should get an address aligned to 8 bytes. Although I set > > CPU_ALIGNMENT and Stack aliment macros to 8 in cpu.h, I still get some > > automatic variables not aligned to 8 bytes, which causes an exception > when > > executing relevant (double) store/load instructions. > > > > I had to apply a brute-force solution to get over this problem. For > example > > I add alignment's attribute to "CORE_mutex_Attributes attr __attribute__ > > ((aligned (8)));" and I set "#define CPU_TIMESTAMP_USE_STRUCT_TIMESPEC > TRUE" > > instead of using CPU_TIMESTAMP_USE_INT64 > > > > Is there any other good solution for such a problem? > > > > Regards, > > Hesham > > > > _______________________________________________ > > devel mailing list > > devel@rtems.org > > http://lists.rtems.org/mailman/listinfo/devel >
_______________________________________________ devel mailing list devel@rtems.org http://lists.rtems.org/mailman/listinfo/devel
