1/* 2 * linux/arch/arm/lib/copy_template.s 3 * 4 * Code template for optimized memory copy functions 5 * 6 * Author: Nicolas Pitre 7 * Created: Sep 28, 2005 8 * Copyright: MontaVista Software, Inc. 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15/* 16 * Theory of operation 17 * ------------------- 18 * 19 * This file provides the core code for a forward memory copy used in 20 * the implementation of memcopy(), copy_to_user() and copy_from_user(). 21 * 22 * The including file must define the following accessor macros 23 * according to the need of the given function: 24 * 25 * ldr1w ptr reg abort 26 * 27 * This loads one word from 'ptr', stores it in 'reg' and increments 28 * 'ptr' to the next word. The 'abort' argument is used for fixup tables. 29 * 30 * ldr4w ptr reg1 reg2 reg3 reg4 abort 31 * ldr8w ptr, reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort 32 * 33 * This loads four or eight words starting from 'ptr', stores them 34 * in provided registers and increments 'ptr' past those words. 35 * The'abort' argument is used for fixup tables. 36 * 37 * ldr1b ptr reg cond abort 38 * 39 * Similar to ldr1w, but it loads a byte and increments 'ptr' one byte. 40 * It also must apply the condition code if provided, otherwise the 41 * "al" condition is assumed by default. 42 * 43 * str1w ptr reg abort 44 * str8w ptr reg1 reg2 reg3 reg4 reg5 reg6 reg7 reg8 abort 45 * str1b ptr reg cond abort 46 * 47 * Same as their ldr* counterparts, but data is stored to 'ptr' location 48 * rather than being loaded. 49 * 50 * enter reg1 reg2 51 * 52 * Preserve the provided registers on the stack plus any additional 53 * data as needed by the implementation including this code. Called 54 * upon code entry. 55 * 56 * usave reg1 reg2 57 * 58 * Unwind annotation macro is corresponding for 'enter' macro. 59 * It tell unwinder that preserved some provided registers on the stack 60 * and additional data by a prior 'enter' macro. 61 * 62 * exit reg1 reg2 63 * 64 * Restore registers with the values previously saved with the 65 * 'preserv' macro. Called upon code termination. 66 * 67 * LDR1W_SHIFT 68 * STR1W_SHIFT 69 * 70 * Correction to be applied to the "ip" register when branching into 71 * the ldr1w or str1w instructions (some of these macros may expand to 72 * than one 32bit instruction in Thumb-2) 73 */ 74 75 76 UNWIND( .fnstart ) 77 enter r4, lr 78 UNWIND( .fnend ) 79 80 UNWIND( .fnstart ) 81 usave r4, lr @ in first stmdb block 82 83 subs r2, r2, #4 84 blt 8f 85 ands ip, r0, #3 86 PLD( pld [r1, #0] ) 87 bne 9f 88 ands ip, r1, #3 89 bne 10f 90 911: subs r2, r2, #(28) 92 stmfd sp!, {r5 - r8} 93 UNWIND( .fnend ) 94 95 UNWIND( .fnstart ) 96 usave r4, lr 97 UNWIND( .save {r5 - r8} ) @ in second stmfd block 98 blt 5f 99 100 CALGN( ands ip, r0, #31 ) 101 CALGN( rsb r3, ip, #32 ) 102 CALGN( sbcnes r4, r3, r2 ) @ C is always set here 103 CALGN( bcs 2f ) 104 CALGN( adr r4, 6f ) 105 CALGN( subs r2, r2, r3 ) @ C gets set 106 CALGN( add pc, r4, ip ) 107 108 PLD( pld [r1, #0] ) 1092: PLD( subs r2, r2, #96 ) 110 PLD( pld [r1, #28] ) 111 PLD( blt 4f ) 112 PLD( pld [r1, #60] ) 113 PLD( pld [r1, #92] ) 114 1153: PLD( pld [r1, #124] ) 1164: ldr8w r1, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f 117 subs r2, r2, #32 118 str8w r0, r3, r4, r5, r6, r7, r8, ip, lr, abort=20f 119 bge 3b 120 PLD( cmn r2, #96 ) 121 PLD( bge 4b ) 122 1235: ands ip, r2, #28 124 rsb ip, ip, #32 125#if LDR1W_SHIFT > 0 126 lsl ip, ip, #LDR1W_SHIFT 127#endif 128 addne pc, pc, ip @ C is always clear here 129 b 7f 1306: 131 .rept (1 << LDR1W_SHIFT) 132 W(nop) 133 .endr 134 ldr1w r1, r3, abort=20f 135 ldr1w r1, r4, abort=20f 136 ldr1w r1, r5, abort=20f 137 ldr1w r1, r6, abort=20f 138 ldr1w r1, r7, abort=20f 139 ldr1w r1, r8, abort=20f 140 ldr1w r1, lr, abort=20f 141 142#if LDR1W_SHIFT < STR1W_SHIFT 143 lsl ip, ip, #STR1W_SHIFT - LDR1W_SHIFT 144#elif LDR1W_SHIFT > STR1W_SHIFT 145 lsr ip, ip, #LDR1W_SHIFT - STR1W_SHIFT 146#endif 147 add pc, pc, ip 148 nop 149 .rept (1 << STR1W_SHIFT) 150 W(nop) 151 .endr 152 str1w r0, r3, abort=20f 153 str1w r0, r4, abort=20f 154 str1w r0, r5, abort=20f 155 str1w r0, r6, abort=20f 156 str1w r0, r7, abort=20f 157 str1w r0, r8, abort=20f 158 str1w r0, lr, abort=20f 159 160 CALGN( bcs 2b ) 161 1627: ldmfd sp!, {r5 - r8} 163 UNWIND( .fnend ) @ end of second stmfd block 164 165 UNWIND( .fnstart ) 166 usave r4, lr @ still in first stmdb block 1678: movs r2, r2, lsl #31 168 ldr1b r1, r3, ne, abort=21f 169 ldr1b r1, r4, cs, abort=21f 170 ldr1b r1, ip, cs, abort=21f 171 str1b r0, r3, ne, abort=21f 172 str1b r0, r4, cs, abort=21f 173 str1b r0, ip, cs, abort=21f 174 175 exit r4, pc 176 1779: rsb ip, ip, #4 178 cmp ip, #2 179 ldr1b r1, r3, gt, abort=21f 180 ldr1b r1, r4, ge, abort=21f 181 ldr1b r1, lr, abort=21f 182 str1b r0, r3, gt, abort=21f 183 str1b r0, r4, ge, abort=21f 184 subs r2, r2, ip 185 str1b r0, lr, abort=21f 186 blt 8b 187 ands ip, r1, #3 188 beq 1b 189 19010: bic r1, r1, #3 191 cmp ip, #2 192 ldr1w r1, lr, abort=21f 193 beq 17f 194 bgt 18f 195 UNWIND( .fnend ) 196 197 198 .macro forward_copy_shift pull push 199 200 UNWIND( .fnstart ) 201 usave r4, lr @ still in first stmdb block 202 subs r2, r2, #28 203 blt 14f 204 205 CALGN( ands ip, r0, #31 ) 206 CALGN( rsb ip, ip, #32 ) 207 CALGN( sbcnes r4, ip, r2 ) @ C is always set here 208 CALGN( subcc r2, r2, ip ) 209 CALGN( bcc 15f ) 210 21111: stmfd sp!, {r5 - r9} 212 UNWIND( .fnend ) 213 214 UNWIND( .fnstart ) 215 usave r4, lr 216 UNWIND( .save {r5 - r9} ) @ in new second stmfd block 217 PLD( pld [r1, #0] ) 218 PLD( subs r2, r2, #96 ) 219 PLD( pld [r1, #28] ) 220 PLD( blt 13f ) 221 PLD( pld [r1, #60] ) 222 PLD( pld [r1, #92] ) 223 22412: PLD( pld [r1, #124] ) 22513: ldr4w r1, r4, r5, r6, r7, abort=19f 226 mov r3, lr, lspull #\pull 227 subs r2, r2, #32 228 ldr4w r1, r8, r9, ip, lr, abort=19f 229 orr r3, r3, r4, lspush #\push 230 mov r4, r4, lspull #\pull 231 orr r4, r4, r5, lspush #\push 232 mov r5, r5, lspull #\pull 233 orr r5, r5, r6, lspush #\push 234 mov r6, r6, lspull #\pull 235 orr r6, r6, r7, lspush #\push 236 mov r7, r7, lspull #\pull 237 orr r7, r7, r8, lspush #\push 238 mov r8, r8, lspull #\pull 239 orr r8, r8, r9, lspush #\push 240 mov r9, r9, lspull #\pull 241 orr r9, r9, ip, lspush #\push 242 mov ip, ip, lspull #\pull 243 orr ip, ip, lr, lspush #\push 244 str8w r0, r3, r4, r5, r6, r7, r8, r9, ip, , abort=19f 245 bge 12b 246 PLD( cmn r2, #96 ) 247 PLD( bge 13b ) 248 249 ldmfd sp!, {r5 - r9} 250 UNWIND( .fnend ) @ end of the second stmfd block 251 252 UNWIND( .fnstart ) 253 usave r4, lr @ still in first stmdb block 25414: ands ip, r2, #28 255 beq 16f 256 25715: mov r3, lr, lspull #\pull 258 ldr1w r1, lr, abort=21f 259 subs ip, ip, #4 260 orr r3, r3, lr, lspush #\push 261 str1w r0, r3, abort=21f 262 bgt 15b 263 CALGN( cmp r2, #0 ) 264 CALGN( bge 11b ) 265 26616: sub r1, r1, #(\push / 8) 267 b 8b 268 UNWIND( .fnend ) 269 270 .endm 271 272 273 forward_copy_shift pull=8 push=24 274 27517: forward_copy_shift pull=16 push=16 276 27718: forward_copy_shift pull=24 push=8 278 279 280/* 281 * Abort preamble and completion macros. 282 * If a fixup handler is required then those macros must surround it. 283 * It is assumed that the fixup code will handle the private part of 284 * the exit macro. 285 */ 286 287 .macro copy_abort_preamble 28819: ldmfd sp!, {r5 - r9} 289 b 21f 29020: ldmfd sp!, {r5 - r8} 29121: 292 .endm 293 294 .macro copy_abort_end 295 ldmfd sp!, {r4, pc} 296 .endm 297 298