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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/nios2/include/asm/checksum.h
26493 views
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/*

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 * Copyright (C) 2010 Tobias Klauser <[email protected]>

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 * Copyright (C) 2004 Microtronix Datacom Ltd.

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 *

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 * This file is subject to the terms and conditions of the GNU General Public

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 * License. See the file "COPYING" in the main directory of this archive

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 * for more details.

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 */

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#ifndef _ASM_NIOS_CHECKSUM_H

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#define _ASM_NIOS_CHECKSUM_H

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/* Take these from lib/checksum.c */

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extern __wsum csum_partial(const void *buff, int len, __wsum sum);

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extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl);

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extern __sum16 ip_compute_csum(const void *buff, int len);

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/*

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 * Fold a partial checksum

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 */

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static inline __sum16 csum_fold(__wsum sum)

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{

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	__asm__ __volatile__(

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		"add	%0, %1, %0\n"

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		"cmpltu	r8, %0, %1\n"

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		"srli	%0, %0, 16\n"

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		"add	%0, %0, r8\n"

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		"nor	%0, %0, %0\n"

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		: "=r" (sum)

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		: "r" (sum << 16), "0" (sum)

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		: "r8");

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	return (__force __sum16) sum;

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}

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/*

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 * computes the checksum of the TCP/UDP pseudo-header

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 * returns a 16-bit checksum, already complemented

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 */

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#define csum_tcpudp_nofold csum_tcpudp_nofold

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static inline __wsum csum_tcpudp_nofold(__be32 saddr, __be32 daddr,

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					__u32 len, __u8 proto,

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					__wsum sum)

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{

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	__asm__ __volatile__(

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		"add	%0, %1, %0\n"

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		"cmpltu	r8, %0, %1\n"

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		"add	%0, %0, r8\n"	/* add carry */

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		"add	%0, %2, %0\n"

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		"cmpltu	r8, %0, %2\n"

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		"add	%0, %0, r8\n"	/* add carry */

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		"add	%0, %3, %0\n"

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		"cmpltu	r8, %0, %3\n"

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		"add	%0, %0, r8\n"	/* add carry */

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		: "=r" (sum), "=r" (saddr)

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		: "r" (daddr), "r" ((len + proto) << 8),

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		  "0" (sum),

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		  "1" (saddr)

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		: "r8");

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	return sum;

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}

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static inline __sum16 csum_tcpudp_magic(__be32 saddr, __be32 daddr,

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					__u32 len, __u8 proto,

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					__wsum sum)

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{

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	return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));

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}

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#endif /* _ASM_NIOS_CHECKSUM_H */

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