Re: [PATCH v2 net-next] net: Implement fast csum_partial for x86_64
From: Hannes Frederic Sowa <hidden>
Date: 2016-01-07 01:52:08
Hi Tom, On 05.01.2016 19:41, Tom Herbert wrote:
quoted hunk ↗ jump to hunk
--- /dev/null +++ b/arch/x86/lib/csum-partial_64.S@@ -0,0 +1,147 @@ +/* Copyright 2016 Tom Herbert <tom@herbertland.com> + * + * Checksum partial calculation + * + * __wsum csum_partial(const void *buff, int len, __wsum sum) + * + * Computes the checksum of a memory block at buff, length len, + * and adds in "sum" (32-bit) + * + * Returns a 32-bit number suitable for feeding into itself + * or csum_tcpudp_magic + * + * Register usage: + * %rdi: argument 1, buff + * %rsi: argument 2, length + * %rdx: argument 3, add in value
I think you forgot to carry-add-in the %rdx register. The assembly code replaces do_csum but not csum_partial. Bye, Hannes