Re: Bug in bswap_64 macro <bits/byteswap.h>

[Henk]

Oops, looked in CVS fixed 17 months ago....

Sorry folks.

H.


Henk wrote:

> Hi,
>
> The __bswap_64 macro fails on my Alpha machine, and may possibly fail on
>
> other 64bits architectures as well...
> The macro uses a union which expands to a 16 byte structure, because
> "unsigned long int " is of size 8 on a 64-bits machine.
>
> To fix it use "unsigned int" for the __l field, better still use in
> bswap_XX fixed size types like __32 __64  .. , or so.
>
> Regards,
>
> Henk
>
> Original bits/byteswap.h macro:
>
> # define __bswap_64(x) \
>      (__extension__
>       ({ union { __extension__ unsigned long long int __ll;
> !!!!! ->                unsigned long int    <-!!!!!!!   __l[2]; } __w,
> __r;
>          if (__builtin_constant_p (x))
>            __r.__ll = __bswap_constant_64(x);
>         else
>          {
>              __w.__ll = (x);
>             __r.__l[0] = __bswap_32(__w.__l[1]);
>             __r.__l[1] = __bswap_32(__w.__l[0]);
>           }
>          __r.__ll; }))