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, 44 insertions, 0 deletions

diff --git a/arch/arm64/lib/memchr.S b/arch/arm64/lib/memchr.S
new file mode 100644
index 0000000..8636b75
--- /dev/null
+++ b/arch/arm64/lib/memchr.S
@@ -0,0 +1,44 @@
+/*
+ * Based on arch/arm/lib/memchr.S
+ *
+ * Copyright (C) 1995-2000 Russell King
+ * 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>
+
+/*
+ * Find a character in an area of memory.
+ *
+ * Parameters:
+ *	x0 - buf
+ *	x1 - c
+ *	x2 - n
+ * Returns:
+ *	x0 - address of first occurrence of 'c' or 0
+ */
+ENTRY(memchr)
+	and	w1, w1, #0xff
+1:	subs	x2, x2, #1
+	b.mi	2f
+	ldrb	w3, [x0], #1
+	cmp	w3, w1
+	b.ne	1b
+	sub	x0, x0, #1
+	ret
+2:	mov	x0, #0
+	ret
+ENDPROC(memchr)