diff options
Diffstat (limited to 'arch/arm64/lib/memmove.S')
-rw-r--r-- | arch/arm64/lib/memmove.S | 57 |
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 0000000..b79fdfa --- /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) |