1 files changed, 57 insertions, 0 deletions

diff --git a/arch/arm64/lib/memmove.S b/arch/arm64/lib/memmove.S
new file mode 100644
index 000000000000..b79fdfa42d39
--- /dev/null
+++ b/arch/arm64/lib/memmove.S
@@ -0,0 +1,57 @@
+/*
+ * Copyright (C) 2013 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+
+/*
+ * Move a buffer from src to test (alignment handled by the hardware).
+ * If dest <= src, call memcpy, otherwise copy in reverse order.
+ *
+ * Parameters:
+ *      x0 - dest
+ *      x1 - src
+ *      x2 - n
+ * Returns:
+ *      x0 - dest
+ */
+ENTRY(memmove)
+        cmp     x0, x1
+        b.ls    memcpy
+        add     x4, x0, x2
+        add     x1, x1, x2
+        subs    x2, x2, #8
+        b.mi    2f
+1:      ldr     x3, [x1, #-8]!
+        subs    x2, x2, #8
+        str     x3, [x4, #-8]!
+        b.pl    1b
+2:      adds    x2, x2, #4
+        b.mi    3f
+        ldr     w3, [x1, #-4]!
+        sub     x2, x2, #4
+        str     w3, [x4, #-4]!
+3:      adds    x2, x2, #2
+        b.mi    4f
+        ldrh    w3, [x1, #-2]!
+        sub     x2, x2, #2
+        strh    w3, [x4, #-2]!
+4:      adds    x2, x2, #1
+        b.mi    5f
+        ldrb    w3, [x1, #-1]
+        strb    w3, [x4, #-1]
+5:      ret
+ENDPROC(memmove)