Re: [PATCH] For RTEMS-LIBBSD support, add bitcount routines

[Sebastian Huber <sebastian dot huber at embedded-brains dot de>]

On 16/05/17 21:04, Craig Howland wrote:
> On 05/16/2017 02:23 PM, Kevin Kirspel wrote:
> > ---
> >   newlib/libc/include/sys/types.h | 66 
> > ++++++++++++++++++++++++++++++++++++++---
> >   1 file changed, 62 insertions(+), 4 deletions(-)
> >
> > diff --git a/newlib/libc/include/sys/types.h 
> > b/newlib/libc/include/sys/types.h
> > index 65ff520..83f891e 100644
> > ...
> > +#ifdef __LP64__
> > +static __inline __uint64_t
> > +__bitcount64(__uint64_t _x)
> > +{
> > ...
> > +}
> > +
> > +#define __bitcountl(x)  __bitcount64((unsigned long)(x))
> > +#else /* __LP64__ */
> > +static __inline __uint64_t
> > +__bitcount64(__uint64_t _x)
> > +{
> > +    return (__bitcount32(_x >> 32) + __bitcount32(_x));
> > +}
> > +
> > +#define __bitcountl(x)  __bitcount32((unsigned long)(x))
> > +#endif /* __LP64__ */
> > +#define __bitcount(x)   __bitcount32((unsigned int)(x))
> > +#endif /* __POPCNT__ */
> > +
> Depending only upon LP64 is not sufficient in general to get all the 
> sizes right.  (ARM Cortex A53, for example, has 64-bit int, 
> too--ILP64.  So A53 would probably end up with two problems, bitcountl 
> and bitcount.) 

RTEMS doesn't support an __ILP64__ ABI at the moment, so it should be 
sufficient. However, maybe we should use the __SIZEOF_INT__ and 
__SIZEOF_LONG__ builtin defines instead of __LP64.

--
Sebastian Huber, embedded brains GmbH

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