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Blackfin arch: Faster Implementation of csum_tcpudp_nofold()

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Avoid conditional branch instructions during carry bit additions.
Special thanks to Bernd.
Simplify: Use ((len + proto) << 8) like every other __LITTLE_ENDIAN__ machine

Cc: Bernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
This commit is contained in:
Michael Hennerich 2009-02-04 16:49:45 +08:00 committed by Bryan Wu
parent 0ce5eaf8ec
commit aa9c33b496
1 changed files with 16 additions and 16 deletions
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32
arch/blackfin/include/asm/checksum.h
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@ -63,23 +63,23 @@ static inline __wsum
csum_tcpudp_nofold(__be32 saddr, __be32 daddr, unsigned short len,
unsigned short proto, __wsum sum)
{
unsigned int carry;
__asm__ ("%0 = %0 + %1;\n\t"
"CC = AC0;\n\t"
"if !CC jump 4;\n\t"
"%0 = %0 + %4;\n\t"
"%0 = %0 + %2;\n\t"
"CC = AC0;\n\t"
"if !CC jump 4;\n\t"
"%0 = %0 + %4;\n\t"
"%0 = %0 + %3;\n\t"
"CC = AC0;\n\t"
"if !CC jump 4;\n\t"
"%0 = %0 + %4;\n\t"
"NOP;\n\t"
: "=d" (sum)
: "d" (daddr), "d" (saddr), "d" ((ntohs(len)<<16)+proto*256), "d" (1), "0"(sum)
: "CC");
__asm__ ("%0 = %0 + %2;\n\t"
"CC = AC0;\n\t"
"%1 = CC;\n\t"
"%0 = %0 + %1;\n\t"
"%0 = %0 + %3;\n\t"
"CC = AC0;\n\t"
"%1 = CC;\n\t"
"%0 = %0 + %1;\n\t"
"%0 = %0 + %4;\n\t"
"CC = AC0;\n\t"
"%1 = CC;\n\t"
"%0 = %0 + %1;\n\t"
: "=d" (sum), "=&d" (carry)
: "d" (daddr), "d" (saddr), "d" ((len + proto) << 8), "0"(sum)
: "CC");
return (sum);
}