diff options
Diffstat (limited to 'kernel/arch/metag/lib/ip_fast_csum.S')
-rw-r--r-- | kernel/arch/metag/lib/ip_fast_csum.S | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/kernel/arch/metag/lib/ip_fast_csum.S b/kernel/arch/metag/lib/ip_fast_csum.S new file mode 100644 index 000000000..533b1e73d --- /dev/null +++ b/kernel/arch/metag/lib/ip_fast_csum.S @@ -0,0 +1,32 @@ + + .text +/* + * This is a version of ip_compute_csum() optimized for IP headers, + * which always checksum on 4 octet boundaries. + * + * extern __sum16 ip_fast_csum(const void *iph, unsigned int ihl); + * + */ + .global _ip_fast_csum + .type _ip_fast_csum,function +_ip_fast_csum: + !! TXRPT needs loops - 1 + SUBS TXRPT,D0Ar2,#1 + MOV D0Re0,#0 + BLO $Lfast_csum_exit +$Lfast_csum_loop: + GETD D1Ar3,[D1Ar1++] + ADDS D0Re0,D0Re0,D1Ar3 + ADDCS D0Re0,D0Re0,#1 + BR $Lfast_csum_loop + LSR D0Ar4,D0Re0,#16 + AND D0Re0,D0Re0,#0xffff + AND D0Ar4,D0Ar4,#0xffff + ADD D0Re0,D0Re0,D0Ar4 + LSR D0Ar4,D0Re0,#16 + ADD D0Re0,D0Re0,D0Ar4 + XOR D0Re0,D0Re0,#-1 + AND D0Re0,D0Re0,#0xffff +$Lfast_csum_exit: + MOV PC,D1RtP + .size _ip_fast_csum,.-_ip_fast_csum |