Re: iso9660 endianness cleanup patch

H. Peter Anvin
2001-05-01T18:17:52Z

Andrzej Krzysztofowicz wrote:
>
> Are you sure that the arguments of the following casting
>
> > + return le16_to_cpu(*(u16 *)p);
>
> > + return be16_to_cpu(*(u16 *)p);
>
> > + return le32_to_cpu(*(u32 *)p);
>
> > + return be32_to_cpu(*(u32 *)p);
>
> are properly aligned ?
> I did not revise the code to check it, but AFAIK improperly aligned
> char* pointers cause problem with casting to pointers to 16/32-bit data
> on some architectures (I heard of sucj a problem with alpha).
>
> Maybe there was a reason that the original code did operate on bytes here...
>

Oh bother, you're right of course. We need some kind of standardized
macro for indirecting through a potentially unaligned pointer. It can
just do the dereference (e.g. x86), use left/right accesses (e.g. MIPS),
or do it by byte (others).

Ports people, what do you think?

-hpa

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