From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH V6 13/33] csky: Library functions
Date: Fri, 28 Sep 2018 09:20:30 -0700
Message-ID: <20180928162030.GE19827@infradead.org>
References: <cover.1538058840.git.ren_guo@c-sky.com>
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To: Guo Ren <ren_guo@c-sky.com>
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> +unsigned long long notrace __bswapdi2(unsigned long long u)
> +{
> +	return (((u) & 0xff00000000000000ull) >> 56) |
> +	       (((u) & 0x00ff000000000000ull) >> 40) |
> +	       (((u) & 0x0000ff0000000000ull) >> 24) |
> +	       (((u) & 0x000000ff00000000ull) >>  8) |
> +	       (((u) & 0x00000000ff000000ull) <<  8) |
> +	       (((u) & 0x0000000000ff0000ull) << 24) |
> +	       (((u) & 0x000000000000ff00ull) << 40) |
> +	       (((u) & 0x00000000000000ffull) << 56);
> +}

How is this any better than using the generic byteswap helpers?

> +unsigned int notrace __bswapsi2(unsigned int u)
> +{
> +	return (((u) & 0xff000000) >> 24) |
> +	       (((u) & 0x00ff0000) >>  8) |
> +	       (((u) & 0x0000ff00) <<  8) |
> +	       (((u) & 0x000000ff) << 24);
> +}

Same here.