diff options
Diffstat (limited to 'include/asm-cris/arch-v32/checksum.h')
| -rw-r--r-- | include/asm-cris/arch-v32/checksum.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/asm-cris/arch-v32/checksum.h b/include/asm-cris/arch-v32/checksum.h new file mode 100644 index 00000000000..a1d6b2a6cc4 --- /dev/null +++ b/include/asm-cris/arch-v32/checksum.h @@ -0,0 +1,29 @@ +#ifndef _ASM_CRIS_ARCH_CHECKSUM_H +#define _ASM_CRIS_ARCH_CHECKSUM_H + +/* + * Check values used in TCP/UDP headers. + * + * The gain of doing this in assembler instead of C, is that C doesn't + * generate carry-additions for the 32-bit components of the + * checksum. Which means it would be necessary to split all those into + * 16-bit components and 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__ __volatile__ ("add.d %2, %0\n\t" + "addc %3, %0\n\t" + "addc %4, %0\n\t" + "addc 0, %0\n\t" + : "=r" (res) + : "0" (sum), "r" (daddr), "r" (saddr), \ + "r" ((ntohs(len) << 16) + (proto << 8))); + + return res; +} + +#endif /* _ASM_CRIS_ARCH_CHECKSUM_H */ |