58 строки
1.3 KiB
ArmAsm
58 строки
1.3 KiB
ArmAsm
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/*
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* Copyright (C) 2013 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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/*
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* Move a buffer from src to test (alignment handled by the hardware).
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* If dest <= src, call memcpy, otherwise copy in reverse order.
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*
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* Parameters:
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* x0 - dest
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* x1 - src
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* x2 - n
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* Returns:
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* x0 - dest
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*/
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ENTRY(memmove)
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cmp x0, x1
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b.ls memcpy
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add x4, x0, x2
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add x1, x1, x2
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subs x2, x2, #8
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b.mi 2f
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1: ldr x3, [x1, #-8]!
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subs x2, x2, #8
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str x3, [x4, #-8]!
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b.pl 1b
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2: adds x2, x2, #4
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b.mi 3f
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ldr w3, [x1, #-4]!
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sub x2, x2, #4
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str w3, [x4, #-4]!
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3: adds x2, x2, #2
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b.mi 4f
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ldrh w3, [x1, #-2]!
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sub x2, x2, #2
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strh w3, [x4, #-2]!
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4: adds x2, x2, #1
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b.mi 5f
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ldrb w3, [x1, #-1]
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strb w3, [x4, #-1]
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5: ret
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ENDPROC(memmove)
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