arm64: klib: Optimised memory functions

This patch introduces AArch64-specific memory functions (memcpy,
memmove, memchr, memset). These functions are not optimised for any CPU
implementation but can be used as a starting point once hardware is
available.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 53 insertions, 0 deletions

diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
new file mode 100644
index 000000000000..27b5003609b6
--- /dev/null
+++ b/arch/arm64/lib/memcpy.S
@@ -0,0 +1,53 @@
+/*
+ * 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>
+
+/*
+ * Copy a buffer from src to dest (alignment handled by the hardware)
+ *
+ * Parameters:
+ *      x0 - dest
+ *      x1 - src
+ *      x2 - n
+ * Returns:
+ *      x0 - dest
+ */
+ENTRY(memcpy)
+        mov     x4, x0
+        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]
+        strb    w3, [x4]
+5:      ret
+ENDPROC(memcpy)