aboutsummaryrefslogtreecommitdiffstats
path: root/arch/arm64/lib/memmove.S
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/lib/memmove.S')
-rw-r--r--arch/arm64/lib/memmove.S57
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)