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Linux kernel mirror (for testing)
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1#ifndef _ASM_CRIS_ARCH_CHECKSUM_H
2#define _ASM_CRIS_ARCH_CHECKSUM_H
3
4/*
5 * Check values used in TCP/UDP headers.
6 *
7 * The gain of doing this in assembler instead of C, is that C doesn't
8 * generate carry-additions for the 32-bit components of the
9 * checksum. Which means it would be necessary to split all those into
10 * 16-bit components and then add.
11 */
12static inline __wsum
13csum_tcpudp_nofold(__be32 saddr, __be32 daddr,
14 unsigned short len, unsigned short proto, __wsum sum)
15{
16 __wsum res;
17
18 __asm__ __volatile__ ("add.d %2, %0\n\t"
19 "addc %3, %0\n\t"
20 "addc %4, %0\n\t"
21 "addc 0, %0\n\t"
22 : "=r" (res)
23 : "0" (sum), "r" (daddr), "r" (saddr), \
24 "r" ((len + proto) << 8));
25
26 return res;
27}
28
29#endif /* _ASM_CRIS_ARCH_CHECKSUM_H */