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>
diff --git a/arch/arm64/lib/memcpy.S b/arch/arm64/lib/memcpy.S
new file mode 100644
index 0000000..27b5003
--- /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)