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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>
| #include <asm/unwind.h>
|
| .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)
| UNWIND( .fnstart )
|
| subs ip, r0, r1
| cmphi r2, ip
| bls memcpy
|
| stmfd sp!, {r0, r4, lr}
| UNWIND( .fnend )
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} ) @ in first stmfd block
| 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}
| UNWIND( .fnend )
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} )
| UNWIND( .save {r5 - r8} ) @ in second stmfd block
| blt 5f
|
| CALGN( ands ip, r0, #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( rsb ip, ip, #32 )
| 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: W(nop)
| W(ldr) r3, [r1, #-4]!
| W(ldr) r4, [r1, #-4]!
| W(ldr) r5, [r1, #-4]!
| W(ldr) r6, [r1, #-4]!
| W(ldr) r7, [r1, #-4]!
| W(ldr) r8, [r1, #-4]!
| W(ldr) lr, [r1, #-4]!
|
| add pc, pc, ip
| nop
| W(nop)
| W(str) r3, [r0, #-4]!
| W(str) r4, [r0, #-4]!
| W(str) r5, [r0, #-4]!
| W(str) r6, [r0, #-4]!
| W(str) r7, [r0, #-4]!
| W(str) r8, [r0, #-4]!
| W(str) lr, [r0, #-4]!
|
| CALGN( bcs 2b )
|
| 7: ldmfd sp!, {r5 - r8}
| UNWIND( .fnend ) @ end of second stmfd block
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
|
| 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
| UNWIND( .fnend )
|
|
| .macro backward_copy_shift push pull
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
| subs r2, r2, #28
| blt 14f
|
| CALGN( ands ip, r0, #31 )
| CALGN( sbcnes r4, ip, r2 ) @ C is always set here
| CALGN( subcc r2, r2, ip )
| CALGN( bcc 15f )
|
| 11: stmfd sp!, {r5 - r9}
| UNWIND( .fnend )
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} )
| UNWIND( .save {r5 - r9} ) @ in new second stmfd block
|
| 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, lspush #\push
| subs r2, r2, #32
| ldmdb r1!, {r3, r4, r5, r6}
| orr lr, lr, ip, lspull #\pull
| mov ip, ip, lspush #\push
| orr ip, ip, r9, lspull #\pull
| mov r9, r9, lspush #\push
| orr r9, r9, r8, lspull #\pull
| mov r8, r8, lspush #\push
| orr r8, r8, r7, lspull #\pull
| mov r7, r7, lspush #\push
| orr r7, r7, r6, lspull #\pull
| mov r6, r6, lspush #\push
| orr r6, r6, r5, lspull #\pull
| mov r5, r5, lspush #\push
| orr r5, r5, r4, lspull #\pull
| mov r4, r4, lspush #\push
| orr r4, r4, r3, lspull #\pull
| stmdb r0!, {r4 - r9, ip, lr}
| bge 12b
| PLD( cmn r2, #96 )
| PLD( bge 13b )
|
| ldmfd sp!, {r5 - r9}
| UNWIND( .fnend ) @ end of the second stmfd block
|
| UNWIND( .fnstart )
| UNWIND( .save {r0, r4, lr} ) @ still in first stmfd block
|
| 14: ands ip, r2, #28
| beq 16f
|
| 15: mov lr, r3, lspush #\push
| ldr r3, [r1, #-4]!
| subs ip, ip, #4
| orr lr, lr, r3, lspull #\pull
| str lr, [r0, #-4]!
| bgt 15b
| CALGN( cmp r2, #0 )
| CALGN( bge 11b )
|
| 16: add r1, r1, #(\pull / 8)
| b 8b
| UNWIND( .fnend )
|
| .endm
|
|
| backward_copy_shift push=8 pull=24
|
| 17: backward_copy_shift push=16 pull=16
|
| 18: backward_copy_shift push=24 pull=8
|
| ENDPROC(memmove)
|
|
