1 /* SPDX-License-Identifier: GPL-2.0-only */ 2 /* 3 * linux/arch/arm/lib/memmove.S 4 * 5 * Author: Nicolas Pitre 6 * Created: Sep 28, 2005 7 * Copyright: (C) MontaVista Software Inc. 8 */ 9 10 #include <linux/linkage.h> 11 #include <asm/assembler.h> 12 #include <asm/unwind.h> 13 14 .text 15 16 /* 17 * Prototype: void *memmove(void *dest, const void *src, size_t n); 18 * 19 * Note: 20 * 21 * If the memory regions don't overlap, we simply branch to memcpy which is 22 * normally a bit faster. Otherwise the copy is done going downwards. This 23 * is a transposition of the code from copy_template.S but with the copy 24 * occurring in the opposite direction. 25 */ 26 27 ENTRY(__memmove) 28 WEAK(memmove) 29 UNWIND( .fnstart ) 30 31 subs ip, r0, r1 32 cmphi r2, ip 33 bls __memcpy 34 UNWIND( .fnend ) 35 36 UNWIND( .fnstart ) 37 UNWIND( .save {r0, r4, fpreg, lr} ) 38 stmfd sp!, {r0, r4, UNWIND(fpreg,) lr} 39 UNWIND( .setfp fpreg, sp ) 40 UNWIND( mov fpreg, sp ) 41 add r1, r1, r2 42 add r0, r0, r2 43 subs r2, r2, #4 44 blt 8f 45 ands ip, r0, #3 46 PLD( pld [r1, #-4] ) 47 bne 9f 48 ands ip, r1, #3 49 bne 10f 50 51 1: subs r2, r2, #(28) 52 stmfd sp!, {r5, r6, r8, r9} 53 blt 5f 54 55 CALGN( ands ip, r0, #31 ) 56 CALGN( sbcsne r4, ip, r2 ) @ C is always set here 57 CALGN( bcs 2f ) 58 CALGN( adr r4, 6f ) 59 CALGN( subs r2, r2, ip ) @ C is set here 60 CALGN( rsb ip, ip, #32 ) 61 CALGN( add pc, r4, ip ) 62 63 PLD( pld [r1, #-4] ) 64 2: PLD( subs r2, r2, #96 ) 65 PLD( pld [r1, #-32] ) 66 PLD( blt 4f ) 67 PLD( pld [r1, #-64] ) 68 PLD( pld [r1, #-96] ) 69 70 3: PLD( pld [r1, #-128] ) 71 4: ldmdb r1!, {r3, r4, r5, r6, r8, r9, ip, lr} 72 subs r2, r2, #32 73 stmdb r0!, {r3, r4, r5, r6, r8, r9, ip, lr} 74 bge 3b 75 PLD( cmn r2, #96 ) 76 PLD( bge 4b ) 77 78 5: ands ip, r2, #28 79 rsb ip, ip, #32 80 addne pc, pc, ip @ C is always clear here 81 b 7f 82 6: W(nop) 83 W(ldr) r3, [r1, #-4]! 84 W(ldr) r4, [r1, #-4]! 85 W(ldr) r5, [r1, #-4]! 86 W(ldr) r6, [r1, #-4]! 87 W(ldr) r8, [r1, #-4]! 88 W(ldr) r9, [r1, #-4]! 89 W(ldr) lr, [r1, #-4]! 90 91 add pc, pc, ip 92 nop 93 W(nop) 94 W(str) r3, [r0, #-4]! 95 W(str) r4, [r0, #-4]! 96 W(str) r5, [r0, #-4]! 97 W(str) r6, [r0, #-4]! 98 W(str) r8, [r0, #-4]! 99 W(str) r9, [r0, #-4]! 100 W(str) lr, [r0, #-4]! 101 102 CALGN( bcs 2b ) 103 104 7: ldmfd sp!, {r5, r6, r8, r9} 105 106 8: movs r2, r2, lsl #31 107 ldrbne r3, [r1, #-1]! 108 ldrbcs r4, [r1, #-1]! 109 ldrbcs ip, [r1, #-1] 110 strbne r3, [r0, #-1]! 111 strbcs r4, [r0, #-1]! 112 strbcs ip, [r0, #-1] 113 ldmfd sp!, {r0, r4, UNWIND(fpreg,) pc} 114 115 9: cmp ip, #2 116 ldrbgt r3, [r1, #-1]! 117 ldrbge r4, [r1, #-1]! 118 ldrb lr, [r1, #-1]! 119 strbgt r3, [r0, #-1]! 120 strbge r4, [r0, #-1]! 121 subs r2, r2, ip 122 strb lr, [r0, #-1]! 123 blt 8b 124 ands ip, r1, #3 125 beq 1b 126 127 10: bic r1, r1, #3 128 cmp ip, #2 129 ldr r3, [r1, #0] 130 beq 17f 131 blt 18f 132 133 134 .macro backward_copy_shift push pull 135 136 subs r2, r2, #28 137 blt 14f 138 139 CALGN( ands ip, r0, #31 ) 140 CALGN( sbcsne r4, ip, r2 ) @ C is always set here 141 CALGN( subcc r2, r2, ip ) 142 CALGN( bcc 15f ) 143 144 11: stmfd sp!, {r5, r6, r8 - r10} 145 146 PLD( pld [r1, #-4] ) 147 PLD( subs r2, r2, #96 ) 148 PLD( pld [r1, #-32] ) 149 PLD( blt 13f ) 150 PLD( pld [r1, #-64] ) 151 PLD( pld [r1, #-96] ) 152 153 12: PLD( pld [r1, #-128] ) 154 13: ldmdb r1!, {r8, r9, r10, ip} 155 mov lr, r3, lspush #\push 156 subs r2, r2, #32 157 ldmdb r1!, {r3, r4, r5, r6} 158 orr lr, lr, ip, lspull #\pull 159 mov ip, ip, lspush #\push 160 orr ip, ip, r10, lspull #\pull 161 mov r10, r10, lspush #\push 162 orr r10, r10, r9, lspull #\pull 163 mov r9, r9, lspush #\push 164 orr r9, r9, r8, lspull #\pull 165 mov r8, r8, lspush #\push 166 orr r8, r8, r6, lspull #\pull 167 mov r6, r6, lspush #\push 168 orr r6, r6, r5, lspull #\pull 169 mov r5, r5, lspush #\push 170 orr r5, r5, r4, lspull #\pull 171 mov r4, r4, lspush #\push 172 orr r4, r4, r3, lspull #\pull 173 stmdb r0!, {r4 - r6, r8 - r10, ip, lr} 174 bge 12b 175 PLD( cmn r2, #96 ) 176 PLD( bge 13b ) 177 178 ldmfd sp!, {r5, r6, r8 - r10} 179 180 14: ands ip, r2, #28 181 beq 16f 182 183 15: mov lr, r3, lspush #\push 184 ldr r3, [r1, #-4]! 185 subs ip, ip, #4 186 orr lr, lr, r3, lspull #\pull 187 str lr, [r0, #-4]! 188 bgt 15b 189 CALGN( cmp r2, #0 ) 190 CALGN( bge 11b ) 191 192 16: add r1, r1, #(\pull / 8) 193 b 8b 194 195 .endm 196 197 198 backward_copy_shift push=8 pull=24 199 200 17: backward_copy_shift push=16 pull=16 201 202 18: backward_copy_shift push=24 pull=8 203 204 UNWIND( .fnend ) 205 ENDPROC(memmove) 206 ENDPROC(__memmove) 207