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Diffstat (limited to 'arch/arm/lib/memmove.S')
| -rw-r--r-- | arch/arm/lib/memmove.S | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S new file mode 100644 index 00000000000..ef7fddc14ac --- /dev/null +++ b/arch/arm/lib/memmove.S @@ -0,0 +1,206 @@ +/* + * 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 + |