> > There are three alignment possibilities for xtensa: no unaligned > > exception, unaligned exception and hardware alignment. In the first > > case unaligned access silently goes to aligned address. It looks like > > it cannot be done via do_unaligned_access, can it? In the third case > > most unaligned accesses are handled transparently by the hardware. > > But e.g. unaligned access by multiprocessor synchronization > > instructions still cause alignment exception. Do I need to implement > > a different alignment checking mechanism for those unhandled cases? > > Case (1), silently going to an aligned address, should be handled > inside the translator by masking the address before the load. See > the ARM and Alpha targets for examples.
This is what gen_load_store_alignment does. > Case (2) and (3) are both handled by using ALIGNED_ONLY. All you > need to do to handle (3) is *not* throw an exception from the > do_unaligned_access function. See how the code is structured > inside softmmu_template.h. > > As for sync insns... You may need to handle it all out-of-line > and check for alignment there. This is also done by gen_load_store_alignment. Does it really worth copying part of this logic to do_unaligned_access just to use ALIGNED_ONLY framework? Thanks. -- Max
