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From: "Hunt, David" <david.hunt@intel.com>
Subject: Re: [PATCH v3 1/6] eal/arm: add 64-bit armv8 version of
 rte_memcpy.h
Date: Mon, 2 Nov 2015 15:49:17 +0000
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To: Jan Viktorin <viktorin@rehivetech.com>
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On 02/11/2015 15:36, Jan Viktorin wrote:
> On Mon, 2 Nov 2015 15:26:19 +0000
--snip--
> It was looking like we can share a lot of common code for both
> architectures. I didn't know how much different are the cpuflags.

CPU flags for ARMv8 are looking like this now. Quite different to the 
ARMv7 ones.

static const struct feature_entry cpu_feature_table[] = {
         FEAT_DEF(FP,        0x00000001, 0, REG_HWCAP,  0)
         FEAT_DEF(ASIMD,     0x00000001, 0, REG_HWCAP,  1)
         FEAT_DEF(EVTSTRM,   0x00000001, 0, REG_HWCAP,  2)
         FEAT_DEF(AES,       0x00000001, 0, REG_HWCAP,  3)
         FEAT_DEF(PMULL,     0x00000001, 0, REG_HWCAP,  4)
         FEAT_DEF(SHA1,      0x00000001, 0, REG_HWCAP,  5)
         FEAT_DEF(SHA2,      0x00000001, 0, REG_HWCAP,  6)
         FEAT_DEF(CRC32,     0x00000001, 0, REG_HWCAP,  7)
         FEAT_DEF(AARCH32,   0x00000001, 0, REG_PLATFORM, 0)
         FEAT_DEF(AARCH64,   0x00000001, 0, REG_PLATFORM, 1)
};

> IMHO, it'd be better to have two directories arm and arm64. I thought
> to refer from arm64 to arm where possible. But I don't know whether is
> this possible with the DPDK build system.

I think both methodologies have their pros and cons. However, I'd lean 
towards the common directory with the "filename_32/64.h" scheme, as that 
similar to the x86 methodology, and we don't need to tweak the include 
paths to pull files from multiple directories.

Dave