linux/include/asm-cris/arch-v10/checksum.h
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

30 lines
744 B
C

#ifndef _CRIS_ARCH_CHECKSUM_H
#define _CRIS_ARCH_CHECKSUM_H
/* Checksum some values used in TCP/UDP headers.
*
* The gain by doing this in asm is that C will not generate carry-additions
* for the 32-bit components of the checksum, so otherwise we would have had
* to split all of those into 16-bit components, then add.
*/
extern inline unsigned int
csum_tcpudp_nofold(unsigned long saddr, unsigned long daddr, unsigned short len,
unsigned short proto, unsigned int sum)
{
int res;
__asm__ ("add.d %2, %0\n\t"
"ax\n\t"
"add.d %3, %0\n\t"
"ax\n\t"
"add.d %4, %0\n\t"
"ax\n\t"
"addq 0, %0\n"
: "=r" (res)
: "0" (sum), "r" (daddr), "r" (saddr), "r" ((ntohs(len) << 16) + (proto << 8)));
return res;
}
#endif