m68knommu: add optimize memmove() function

Add an m68k/coldfire optimized memmove() function for the m68knommu arch.
This is the same function as used by m68k. Simple speed tests show this
is faster once buffers are larger than 4 bytes, and significantly faster
on much larger buffers (4 times faster above about 100 bytes).

This also goes part of the way to fixing a regression caused by commit
ea61bc461d09e8d331a307916530aaae808c72a2 ("m68k/m68knommu: merge MMU and
non-MMU string.h"), which breaks non-coldfire non-mmu builds (which is
the 68x328 and 68360 families). They currently have no memmove() fucntion
defined, since there was none in the m68knommu/lib functions.

Signed-off-by: Greg Ungerer <gerg@uclinux.org>

2 files changed, 106 insertions, 1 deletions

diff --git a/arch/m68knommu/lib/Makefile b/arch/m68knommu/lib/Makefile
index d94d709665aa..32d852e586d7 100644
--- a/arch/m68knommu/lib/Makefile
+++ b/arch/m68knommu/lib/Makefile
@@ -4,4 +4,4 @@
 
 lib-y   := ashldi3.o ashrdi3.o lshrdi3.o \
            muldi3.o mulsi3.o divsi3.o udivsi3.o modsi3.o umodsi3.o \
-           checksum.o memcpy.o memset.o delay.o
+           checksum.o memcpy.o memmove.o memset.o delay.o
diff --git a/arch/m68knommu/lib/memmove.c b/arch/m68knommu/lib/memmove.c
new file mode 100644
index 000000000000..b3dcfe9dab7e
--- /dev/null
+++ b/arch/m68knommu/lib/memmove.c
@@ -0,0 +1,105 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#define __IN_STRING_C
+
+#include <linux/module.h>
+#include <linux/string.h>
+
+void *memmove(void *dest, const void *src, size_t n)
+{
+        void *xdest = dest;
+        size_t temp;
+
+        if (!n)
+                return xdest;
+
+        if (dest < src) {
+                if ((long)dest & 1) {
+                        char *cdest = dest;
+                        const char *csrc = src;
+                        *cdest++ = *csrc++;
+                        dest = cdest;
+                        src = csrc;
+                        n--;
+                }
+                if (n > 2 && (long)dest & 2) {
+                        short *sdest = dest;
+                        const short *ssrc = src;
+                        *sdest++ = *ssrc++;
+                        dest = sdest;
+                        src = ssrc;
+                        n -= 2;
+                }
+                temp = n >> 2;
+                if (temp) {
+                        long *ldest = dest;
+                        const long *lsrc = src;
+                        temp--;
+                        do
+                                *ldest++ = *lsrc++;
+                        while (temp--);
+                        dest = ldest;
+                        src = lsrc;
+                }
+                if (n & 2) {
+                        short *sdest = dest;
+                        const short *ssrc = src;
+                        *sdest++ = *ssrc++;
+                        dest = sdest;
+                        src = ssrc;
+                }
+                if (n & 1) {
+                        char *cdest = dest;
+                        const char *csrc = src;
+                        *cdest = *csrc;
+                }
+        } else {
+                dest = (char *)dest + n;
+                src = (const char *)src + n;
+                if ((long)dest & 1) {
+                        char *cdest = dest;
+                        const char *csrc = src;
+                        *--cdest = *--csrc;
+                        dest = cdest;
+                        src = csrc;
+                        n--;
+                }
+                if (n > 2 && (long)dest & 2) {
+                        short *sdest = dest;
+                        const short *ssrc = src;
+                        *--sdest = *--ssrc;
+                        dest = sdest;
+                        src = ssrc;
+                        n -= 2;
+                }
+                temp = n >> 2;
+                if (temp) {
+                        long *ldest = dest;
+                        const long *lsrc = src;
+                        temp--;
+                        do
+                                *--ldest = *--lsrc;
+                        while (temp--);
+                        dest = ldest;
+                        src = lsrc;
+                }
+                if (n & 2) {
+                        short *sdest = dest;
+                        const short *ssrc = src;
+                        *--sdest = *--ssrc;
+                        dest = sdest;
+                        src = ssrc;
+                }
+                if (n & 1) {
+                        char *cdest = dest;
+                        const char *csrc = src;
+                        *--cdest = *--csrc;
+                }
+        }
+        return xdest;
+}
+EXPORT_SYMBOL(memmove);