As I understand it, alignment is modulo whatever the given platform supports.
If the components on MIPS only support, say, 16 bytes (which I'm just pulling out of thin air), then specifying __attribute__((__aligned__(256))) will be ineffective.
Some platforms only support alignments of 4. Others 8 or 16. I don't know what MIPS supports.
In this case, when I say "platform", that comprises the OS as well as the assembler and linker. Least useful denominator rule applies.
Also note, some (most?) platforms require that the alignment be a one of 2^x (where x is 0 to some "n"). So if you tested __attribute__((__aligned__(3))) for a RGB quantity, for example, I wouldn't be surprised to find out that it wasn't honored everywhere as one may expect. Caveat emptor!
HTH, --Eljay
