On Fri, 18 Sep 2009 17:23:36 -0600
Jason Gunthorpe <jguntho...@obsidianresearch.com> wrote:
> On Fri, Sep 18, 2009 at 03:28:48PM -0700, Ira Weiny wrote:
>
> > One is for static defines CL_NTOH and the other is for variables at
> > run time. I found this code in Linux.
>
> Thats gross, and is exactly why you don't do this yourself...
>
> bswap64/32/16 do this all automatically. ntohl also do it and are more
> portable.
>
> from glibc:
>
> # define ntohl(x) __bswap_32 (x)
> #define bswap_32(x) __bswap_32 (x)
> # define __bswap_32(x) \
> (__extension__
> \
> ({ register unsigned int __v, __x = (x);
> \
> if (__builtin_constant_p (__x))
> \
> __v = __bswap_constant_32 (__x);
> \
> else
> \
> __asm__ ("bswap %0" : "=r" (__v) : "0" (__x));
> \
> __v; }))
>
>
> I'd say just use the ntohl, ntohs, and bswap64 macros directly and
> Window can provide headers with whatever it needs instead. They are
> already doing this..
I agree but ntohl etc do not seem to work for the macros which are defined.
osm_sa_mad_ctrl.c: In function 'sa_mad_ctrl_process':
osm_sa_mad_ctrl.c:140: error: case label does not reduce to an integer constant
...
switch (p_sa_mad->attr_id) {
case IB_MAD_ATTR_CLASS_PORT_INFO:
...
>From ib_types.h
#define IB_MAD_ATTR_CLASS_PORT_INFO (CL_HTON16(0x0001))
Thus the
#define __bswap_constant_16(x) \
((((x) >> 8) & 0xff) | (((x) & 0xff) << 8))
in bits/byteswap.h
Ira
>
> Ditto for stdint.h and stdbool.h. Those are C99 headers, just use them.
>
> Jason
--
Ira Weiny
Math Programmer/Computer Scientist
Lawrence Livermore National Lab
925-423-8008
wei...@llnl.gov
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