Re: [dpdk-dev] [PATCH 1/3] librte_hash: Fix unsupported instruction `crc32' in i686 platform

[Yerden Zhumabekov <e_zhumabekov@sts.kz>]

Hi Michael,

Thanks for this patch, in fact I didn't try to compile it on i686 when
developing original software fallback for CRC32.

I think if we want to make code compilable as wide as possible, we
should compile out all SSE4.2 instructions. As to the patch, we may
compile out 'crc32l' instruction emitting code if the arch is not x86.
This concerns two functions: crc32c_sse42_u32() and
crc32c_sse42_u64_mimic().

The compile check might be something like this:

#if defined(RTE_ARCH_I686) || defined(RTE_ARCH_X86_64)
#endif

Otherwise, the patch looks good.

05.03.2015 19:15, Michael Qiu пишет:
> CC rte_hash.o
> Error: unsupported instruction `crc32'
>
> The root cause is that i686 platform does not support 'crc32q'
> Need make it only available in x86_64 platform
>
> Signed-off-by: Michael Qiu <michael.qiu@intel.com>
> ---
>  lib/librte_hash/rte_hash_crc.h | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h
> index d28bb2a..4e9546f 100644
> --- a/lib/librte_hash/rte_hash_crc.h
> +++ b/lib/librte_hash/rte_hash_crc.h
> @@ -374,6 +374,7 @@ crc32c_sse42_u32(uint32_t data, uint32_t init_val)
>  	return init_val;
>  }
>  
> +#ifdef RTE_ARCH_X86_64
>  static inline uint32_t
>  crc32c_sse42_u64(uint64_t data, uint64_t init_val)
>  {
> @@ -383,6 +384,7 @@ crc32c_sse42_u64(uint64_t data, uint64_t init_val)
>  			: [data] "rm" (data));
>  	return init_val;
>  }
> +#endif
>  
>  static inline uint32_t
>  crc32c_sse42_u64_mimic(uint64_t data, uint64_t init_val)
> @@ -476,8 +478,10 @@ rte_hash_crc_4byte(uint32_t data, uint32_t init_val)
>  static inline uint32_t
>  rte_hash_crc_8byte(uint64_t data, uint32_t init_val)
>  {
> +#ifdef RTE_ARCH_X86_64
>  	if (likely(crc32_alg == CRC32_SSE42_x64))
>  		return crc32c_sse42_u64(data, init_val);
> +#endif
>  
>  	if (likely(crc32_alg & CRC32_SSE42))
>  		return crc32c_sse42_u64_mimic(data, init_val);

-- 
Sincerely,

Yerden Zhumabekov
State Technical Service
Astana, KZ