/* * 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 <assembler.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. */ .type memmove, function .globl memmove 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, 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} 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, 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} 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