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

[Sebastian Huber <sebastian.huber@embedded-brains.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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