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/*
* linux/arch/arm/lib/memmove.S
*
* Author: Nicolas Pitre
* Created: Sep 28, 2005
* Copyright: (C) MontaVista Software Inc.
*
* 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.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* This can be used to enable code to cacheline align the source pointer.
* Experiments on tested architectures (StrongARM and XScale) didn't show
* this a worthwhile thing to do. That might be different in the future.
*/
//#define CALGN(code...) code
#define CALGN(code...)
.text
/*
* Prototype: void *memmove(void *dest, const void *src, size_t n);
*
* Note:
*
* If the memory regions don't overlap, we simply branch to memcpy which is
* normally a bit faster. Otherwise the copy is done going downwards. This
* is a transposition of the code from copy_template.S but with the copy
* occurring in the opposite direction.
*/
ENTRY(memmove)
subs ip, r0, r1
cmphi r2, ip
bls memcpy
stmfd sp!, {r0, r4, lr}
add r1, r1, r2
add r0, r0, r2
subs r2, r2, #4
blt 8f
ands ip, r0, #3
PLD( pld [r1, #-4] )
bne 9f
ands ip, r1, #3
bne 10f
1: subs r2, r2, #(28)
stmfd sp!, {r5 - r8}
blt 5f
CALGN( ands ip, r1, #31 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( bcs 2f )
CALGN( adr r4, 6f )
CALGN( subs r2, r2, ip ) @ C is set here
CALGN( add pc, r4, ip )
PLD( pld [r1, #-4] )
2: PLD( subs r2, r2, #96 )
PLD( pld [r1, #-32] )
PLD( blt 4f )
PLD( pld [r1, #-64] )
PLD( pld [r1, #-96] )
3: PLD( pld [r1, #-128] )
4: ldmdb r1!, {r3, r4, r5, r6, r7, r8, ip, lr}
subs r2, r2, #32
stmdb r0!, {r3, r4, r5, r6, r7, r8, ip, lr}
bge 3b
PLD( cmn r2, #96 )
PLD( bge 4b )
5: ands ip, r2, #28
rsb ip, ip, #32
addne pc, pc, ip @ C is always clear here
b 7f
6: nop
ldr r3, [r1, #-4]!
ldr r4, [r1, #-4]!
ldr r5, [r1, #-4]!
ldr r6, [r1, #-4]!
ldr r7, [r1, #-4]!
ldr r8, [r1, #-4]!
ldr lr, [r1, #-4]!
add pc, pc, ip
nop
nop
str r3, [r0, #-4]!
str r4, [r0, #-4]!
str r5, [r0, #-4]!
str r6, [r0, #-4]!
str r7, [r0, #-4]!
str r8, [r0, #-4]!
str lr, [r0, #-4]!
CALGN( bcs 2b )
7: ldmfd sp!, {r5 - r8}
8: movs r2, r2, lsl #31
ldrneb r3, [r1, #-1]!
ldrcsb r4, [r1, #-1]!
ldrcsb ip, [r1, #-1]
strneb r3, [r0, #-1]!
strcsb r4, [r0, #-1]!
strcsb ip, [r0, #-1]
ldmfd sp!, {r0, r4, pc}
9: cmp ip, #2
ldrgtb r3, [r1, #-1]!
ldrgeb r4, [r1, #-1]!
ldrb lr, [r1, #-1]!
strgtb r3, [r0, #-1]!
strgeb r4, [r0, #-1]!
subs r2, r2, ip
strb lr, [r0, #-1]!
blt 8b
ands ip, r1, #3
beq 1b
10: bic r1, r1, #3
cmp ip, #2
ldr r3, [r1, #0]
beq 17f
blt 18f
.macro backward_copy_shift push pull
subs r2, r2, #28
blt 14f
CALGN( ands ip, r1, #31 )
CALGN( rsb ip, ip, #32 )
CALGN( sbcnes r4, ip, r2 ) @ C is always set here
CALGN( subcc r2, r2, ip )
CALGN( bcc 15f )
11: stmfd sp!, {r5 - r9}
PLD( pld [r1, #-4] )
PLD( subs r2, r2, #96 )
PLD( pld [r1, #-32] )
PLD( blt 13f )
PLD( pld [r1, #-64] )
PLD( pld [r1, #-96] )
12: PLD( pld [r1, #-128] )
13: ldmdb r1!, {r7, r8, r9, ip}
mov lr, r3, push #\push
subs r2, r2, #32
ldmdb r1!, {r3, r4, r5, r6}
orr lr, lr, ip, pull #\pull
mov ip, ip, push #\push
orr ip, ip, r9, pull #\pull
mov r9, r9, push #\push
orr r9, r9, r8, pull #\pull
mov r8, r8, push #\push
orr r8, r8, r7, pull #\pull
mov r7, r7, push #\push
orr r7, r7, r6, pull #\pull
mov r6, r6, push #\push
orr r6, r6, r5, pull #\pull
mov r5, r5, push #\push
orr r5, r5, r4, pull #\pull
mov r4, r4, push #\push
orr r4, r4, r3, pull #\pull
stmdb r0!, {r4 - r9, ip, lr}
bge 12b
PLD( cmn r2, #96 )
PLD( bge 13b )
ldmfd sp!, {r5 - r9}
14: ands ip, r2, #28
beq 16f
15: mov lr, r3, push #\push
ldr r3, [r1, #-4]!
subs ip, ip, #4
orr lr, lr, r3, pull #\pull
str lr, [r0, #-4]!
bgt 15b
CALGN( cmp r2, #0 )
CALGN( bge 11b )
16: add r1, r1, #(\pull / 8)
b 8b
.endm
backward_copy_shift push=8 pull=24
17: backward_copy_shift push=16 pull=16
18: backward_copy_shift push=24 pull=8
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