From 5ce02c323b1102c1e603754be5b492d238ee3af7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Niels=20M=C3=B6ller?= <nisse@lysator.liu.se>
Date: Thu, 23 Oct 2014 13:07:36 +0200
Subject: [PATCH] Two-way unrolling of aligned memxor3.
---
ChangeLog | 1 +
memxor.c | 13 +++++++++++--
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 8311fec9..8ecfb343 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -2,6 +2,7 @@
* memxor.c (memxor_common_alignment, memxor_different_alignment)
(memxor): Change loop order, iterate from the end.
+ (memxor3_common_alignment): Unroll twice.
* examples/nettle-benchmark.c (time_memxor): Allocate buffers as
arrays of unsigned long, for more reliable alignment.
diff --git a/memxor.c b/memxor.c
index e205aba8..0e60e35d 100644
--- a/memxor.c
+++ b/memxor.c
@@ -166,8 +166,17 @@ memxor3_common_alignment (word_t *dst,
const word_t *a, const word_t *b, size_t n)
{
/* FIXME: Require n > 0? */
- while (n-- > 0)
- dst[n] = a[n] ^ b[n];
+ if (n & 1)
+ {
+ n--;
+ dst[n] = a[n] ^ b[n];
+ }
+ while (n > 0)
+ {
+ n -= 2;
+ dst[n+1] = a[n+1] ^ b[n+1];
+ dst[n] = a[n] ^ b[n];
+ }
}
static void
--
GitLab