The C version of csum_add() as defined in include/net/checksum.h gives the
following assembly:
0: 7c 04 1a 14 add r0,r4,r3
4: 7c 64 00 10 subfc r3,r4,r0
8: 7c 63 19 10 subfe r3,r3,r3
c: 7c 63 00 50 subf r3,r3,r0
include/net/checksum.h also offers the possibility to define an arch specific
function.
This patch provides a ppc32 specific csum_add() inline function.
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
---
arch/powerpc/include/asm/checksum.h | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/arch/powerpc/include/asm/checksum.h
b/arch/powerpc/include/asm/checksum.h
index cfe806a..a13aa1f 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -141,6 +141,19 @@ static inline __sum16 csum_tcpudp_magic(__be32 saddr,
__be32 daddr,
{
return csum_fold(csum_tcpudp_nofold(saddr, daddr, len, proto, sum));
}
+
+#define HAVE_ARCH_CSUM_ADD
+static inline __wsum csum_add(__wsum csum, __wsum addend)
+{
+ __asm__("\n\
+ addc %0,%0,%1 \n\
+ addze %0,%0 \n\
+ "
+ : "=r" (csum)
+ : "r" (addend), "0"(csum));
+ return csum;
+}
+
#endif
#endif
#endif /* __KERNEL__ */
--
2.1.0
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