30 lines
825 B
C
30 lines
825 B
C
#ifndef _ASM_CRIS_ARCH_CHECKSUM_H
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#define _ASM_CRIS_ARCH_CHECKSUM_H
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/*
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* Check values used in TCP/UDP headers.
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*
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* The gain of doing this in assembler instead of C, is that C doesn't
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* generate carry-additions for the 32-bit components of the
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* checksum. Which means it would be necessary to split all those into
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* 16-bit components and then add.
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*/
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extern inline unsigned int
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csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr,
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unsigned short len, unsigned short proto, unsigned int sum)
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{
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int res;
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__asm__ __volatile__ ("add.d %2, %0\n\t"
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"addc %3, %0\n\t"
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"addc %4, %0\n\t"
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"addc 0, %0\n\t"
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: "=r" (res)
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: "0" (sum), "r" (daddr), "r" (saddr), \
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"r" ((ntohs(len) << 16) + (proto << 8)));
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return res;
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}
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#endif /* _ASM_CRIS_ARCH_CHECKSUM_H */
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