Re: [dpdk-dev] [PATCH 1/3 v2] librte_hash: Fix unsupported instruction `crc32' in i686 platform

[Thomas Monjalon <thomas.monjalon@6wind.com>]

2015-03-06 00:55, Michael Qiu:
> 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>
> ---
> v2 --> v1:
>          Make crc32 instruction only works in X86 platform
>  lib/librte_hash/rte_hash_crc.h | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/lib/librte_hash/rte_hash_crc.h b/lib/librte_hash/rte_hash_crc.h
> index d28bb2a..c0a789e 100644
> --- a/lib/librte_hash/rte_hash_crc.h
> +++ b/lib/librte_hash/rte_hash_crc.h
> @@ -364,6 +364,7 @@ crc32c_2words(uint64_t data, uint32_t init_val)
>  	return crc;
>  }
>  
> +#if defined RTE_ARCH_I686 || defined RTE_ARCH_X86_64
>  static inline uint32_t
>  crc32c_sse42_u32(uint32_t data, uint32_t init_val)
>  {
> @@ -373,7 +374,9 @@ crc32c_sse42_u32(uint32_t data, uint32_t init_val)
>  			: [data] "rm" (data));
>  	return init_val;
>  }
> +#endif

Wouldn't it be more elegant to define a stub which returns 0 in #else
in order to remove #ifdef below?
Not sure, matter of taste.

[...]
> @@ -455,8 +461,10 @@ rte_hash_crc_init_alg(void)
>  static inline uint32_t
>  rte_hash_crc_4byte(uint32_t data, uint32_t init_val)
>  {
> +#if defined RTE_ARCH_I686 || defined RTE_ARCH_X86_64
>  	if (likely(crc32_alg & CRC32_SSE42))
>  		return crc32c_sse42_u32(data, init_val);
> +#endif
>  
>  	return crc32c_1word(data, init_val);
>  }
> @@ -476,11 +484,15 @@ 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 defined RTE_ARCH_I686 || defined RTE_ARCH_X86_64
>  	if (likely(crc32_alg & CRC32_SSE42))
>  		return crc32c_sse42_u64_mimic(data, init_val);
> +#endif
>  
>  	return crc32c_2words(data, init_val);
>  }
>