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   1 /***************************************************************************
   2  *   Copyright (C) 2006 by Dominic Rath                                    *
   3  *   Dominic.Rath@gmx.de                                                   *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15  *   You should have received a copy of the GNU General Public License     *
  16  *   along with this program; if not, write to the                         *
  17  *   Free Software Foundation, Inc.,                                       *
  18  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  19  ***************************************************************************/
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include "target.h"
  25 #include "armv4_5.h"
  26 #include "arm_disassembler.h"
  27 #include "arm_simulator.h"
  28 #include "log.h"
  29 #include "binarybuffer.h"
  30
  31 #include <string.h>
  32
  33 u32 arm_shift(u8 shift, u32 Rm, u32 shift_amount, u8 *carry)
  34 {
  35         u32 return_value;
  36         shift_amount &= 0xff;
  37
  38         if (shift == 0x0) /* LSL */
  39         {
  40                 if ((shift_amount > 0) && (shift_amount <= 32))
  41                 {
  42                         return_value = Rm << shift_amount;
  43                         *carry = Rm >> (32 - shift_amount);
  44                 }
  45                 else if (shift_amount > 32)
  46                 {
  47                         return_value = 0x0;
  48                         *carry = 0x0;
  49                 }
  50                 else /* (shift_amount == 0) */
  51                 {
  52                         return_value = Rm;
  53                 }
  54         }
  55         else if (shift == 0x1) /* LSR */
  56         {
  57                 if ((shift_amount > 0) && (shift_amount <= 32))
  58                 {
  59                         return_value = Rm >> shift_amount;
  60                         *carry = (Rm >> (shift_amount - 1)) & 1;
  61                 }
  62                 else if (shift_amount > 32)
  63                 {
  64                         return_value = 0x0;
  65                         *carry = 0x0;
  66                 }
  67                 else /* (shift_amount == 0) */
  68                 {
  69                         return_value = Rm;
  70                 }
  71         }
  72         else if (shift == 0x2) /* ASR */
  73         {
  74                 if ((shift_amount > 0) && (shift_amount <= 32))
  75                 {
  76                         /* right shifts of unsigned values are guaranteed to be logical (shift in zeroes)
  77                          * simulate an arithmetic shift (shift in signed-bit) by adding the signed-bit manually */
  78                         return_value = Rm >> shift_amount;
  79                         if (Rm & 0x80000000)
  80                                 return_value |= 0xffffffff << (32 - shift_amount);
  81                 }
  82                 else if (shift_amount > 32)
  83                 {
  84                         if (Rm & 0x80000000)
  85                         {
  86                                 return_value = 0xffffffff;
  87                                 *carry = 0x1;
  88                         }
  89                         else
  90                         {
  91                                 return_value = 0x0;
  92                                 *carry = 0x0;
  93                         }
  94                 }
  95                 else /* (shift_amount == 0) */
  96                 {
  97                         return_value = Rm;
  98                 }
  99         }
 100         else if (shift == 0x3) /* ROR */
 101         {
 102                 if (shift_amount == 0)
 103                 {
 104                         return_value = Rm;
 105                 }
 106                 else
 107                 {
 108                         shift_amount = shift_amount % 32;
 109                         return_value = (Rm >> shift_amount) | (Rm << (32 - shift_amount));
 110                         *carry = (return_value >> 31) & 0x1;
 111                 }
 112         }
 113         else if (shift == 0x4) /* RRX */
 114         {
 115                 return_value = Rm >> 1;
 116                 if (*carry)
 117                         Rm |= 0x80000000;
 118                 *carry = Rm & 0x1;
 119         }
 120
 121         return return_value;
 122 }
 123
 124 u32 arm_shifter_operand(armv4_5_common_t *armv4_5, int variant, union arm_shifter_operand shifter_operand, u8 *shifter_carry_out)
 125 {
 126         u32 return_value;
 127         int instruction_size;
 128
 129         if (armv4_5->core_state == ARMV4_5_STATE_ARM)
 130                 instruction_size = 4;
 131         else
 132                 instruction_size = 2;
 133
 134         *shifter_carry_out = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
 135
 136         if (variant == 0) /* 32-bit immediate */
 137         {
 138                 return_value = shifter_operand.immediate.immediate;
 139         }
 140         else if (variant == 1) /* immediate shift */
 141         {
 142                 u32 Rm = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, shifter_operand.immediate_shift.Rm).value, 0, 32);
 143
 144                 /* adjust RM in case the PC is being read */
 145                 if (shifter_operand.immediate_shift.Rm == 15)
 146                         Rm += 2 * instruction_size;
 147
 148                 return_value = arm_shift(shifter_operand.immediate_shift.shift, Rm, shifter_operand.immediate_shift.shift_imm, shifter_carry_out);
 149         }
 150         else if (variant == 2) /* register shift */
 151         {
 152                 u32 Rm = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, shifter_operand.register_shift.Rm).value, 0, 32);
 153                 u32 Rs = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, shifter_operand.register_shift.Rs).value, 0, 32);
 154
 155                 /* adjust RM in case the PC is being read */
 156                 if (shifter_operand.register_shift.Rm == 15)
 157                         Rm += 2 * instruction_size;
 158
 159                 return_value = arm_shift(shifter_operand.immediate_shift.shift, Rm, Rs, shifter_carry_out);
 160         }
 161         else
 162         {
 163                 ERROR("BUG: shifter_operand.variant not 0, 1 or 2");
 164                 return_value = 0xffffffff;
 165         }
 166
 167         return return_value;
 168 }
 169
 170 int pass_condition(u32 cpsr, u32 opcode)
 171 {
 172         switch ((opcode & 0xf0000000) >> 28)
 173         {
 174                 case 0x0:       /* EQ */
 175                         if (cpsr & 0x40000000)
 176                                 return 1;
 177                         else
 178                                 return 0;
 179                 case 0x1:       /* NE */
 180                         if (!(cpsr & 0x40000000))
 181                                 return 1;
 182                         else
 183                                 return 0;
 184                 case 0x2:       /* CS */
 185                         if (cpsr & 0x20000000)
 186                                 return 1;
 187                         else
 188                                 return 0;
 189                 case 0x3:       /* CC */
 190                         if (!(cpsr & 0x20000000))
 191                                 return 1;
 192                         else
 193                                 return 0;
 194                 case 0x4:       /* MI */
 195                         if (cpsr & 0x80000000)
 196                                 return 1;
 197                         else
 198                                 return 0;
 199                 case 0x5:       /* PL */
 200                         if (!(cpsr & 0x80000000))
 201                                 return 1;
 202                         else
 203                                 return 0;
 204                 case 0x6:       /* VS */
 205                         if (cpsr & 0x10000000)
 206                                 return 1;
 207                         else
 208                                 return 0;
 209                 case 0x7:       /* VC */
 210                         if (!(cpsr & 0x10000000))
 211                                 return 1;
 212                         else
 213                                 return 0;
 214                 case 0x8:       /* HI */
 215                         if ((cpsr & 0x20000000) && !(cpsr & 0x40000000))
 216                                 return 1;
 217                         else
 218                                 return 0;
 219                 case 0x9:       /* LS */
 220                         if (!(cpsr & 0x20000000) || (cpsr & 0x40000000))
 221                                 return 1;
 222                         else
 223                                 return 0;
 224                 case 0xa:       /* GE */
 225                         if (((cpsr & 0x80000000) && (cpsr & 0x10000000))
 226                                 || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000)))
 227                                 return 1;
 228                         else
 229                                 return 0;
 230                 case 0xb:       /* LT */
 231                         if (((cpsr & 0x80000000) && !(cpsr & 0x10000000))
 232                                 || (!(cpsr & 0x80000000) && (cpsr & 0x10000000)))
 233                                 return 1;
 234                         else
 235                                 return 0;
 236                 case 0xc:       /* GT */
 237                         if (!(cpsr & 0x40000000) &&
 238                                 (((cpsr & 0x80000000) && (cpsr & 0x10000000))
 239                                 || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000))))
 240                                 return 1;
 241                         else
 242                                 return 0;
 243                 case 0xd:       /* LE */
 244                         if ((cpsr & 0x40000000) &&
 245                                 (((cpsr & 0x80000000) && !(cpsr & 0x10000000))
 246                                 || (!(cpsr & 0x80000000) && (cpsr & 0x10000000))))
 247                                 return 1;
 248                         else
 249                                 return 0;
 250                 case 0xe:
 251                 case 0xf:
 252                         return 1;
 253
 254         }
 255
 256         ERROR("BUG: should never get here");
 257         return 0;
 258 }
 259
 260 int thumb_pass_branch_condition(u32 cpsr, u16 opcode)
 261 {
 262         return pass_condition(cpsr, (opcode & 0x0f00) << 20);
 263 }
 264
 265 /* simulate a single step (if possible)
 266  * if the dry_run_pc argument is provided, no state is changed,
 267  * but the new pc is stored in the variable pointed at by the argument
 268  */
 269 int arm_simulate_step(target_t *target, u32 *dry_run_pc)
 270 {
 271         armv4_5_common_t *armv4_5 = target->arch_info;
 272         u32 opcode;
 273         u32 current_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
 274         arm_instruction_t instruction;
 275         int instruction_size;
 276
 277         if (armv4_5->core_state == ARMV4_5_STATE_ARM)
 278         {
 279                 /* get current instruction, and identify it */
 280                 target_read_u32(target, current_pc, &opcode);
 281                 arm_evaluate_opcode(opcode, current_pc, &instruction);
 282                 instruction_size = 4;
 283
 284                 /* check condition code (for all instructions) */
 285                 if (!pass_condition(buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32), opcode))
 286                 {
 287                         if (dry_run_pc)
 288                         {
 289                                 *dry_run_pc = current_pc + instruction_size;
 290                         }
 291                         else
 292                         {
 293                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
 294                         }
 295
 296                         return ERROR_OK;
 297                 }
 298         }
 299         else
 300         {
 301                 target_read_u32(target, current_pc, &opcode);
 302                 arm_evaluate_opcode(opcode, current_pc, &instruction);
 303                 instruction_size = 2;
 304
 305                 /* check condition code (only for branch instructions) */
 306                 if ((!thumb_pass_branch_condition(buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32), opcode)) &&
 307                         (instruction.type == ARM_B))
 308                 {
 309                         if (dry_run_pc)
 310                         {
 311                                 *dry_run_pc = current_pc + instruction_size;
 312                         }
 313                         else
 314                         {
 315                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
 316                         }
 317
 318                         return ERROR_OK;
 319                 }
 320         }
 321
 322         /* examine instruction type */
 323
 324         /* branch instructions */
 325         if ((instruction.type >= ARM_B) && (instruction.type <= ARM_BLX))
 326         {
 327                 u32 target;
 328
 329                 if (instruction.info.b_bl_bx_blx.reg_operand == -1)
 330                 {
 331                         target = instruction.info.b_bl_bx_blx.target_address;
 332                 }
 333                 else
 334                 {
 335                         target = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.b_bl_bx_blx.reg_operand).value, 0, 32);
 336                 }
 337
 338                 if (dry_run_pc)
 339                 {
 340                         *dry_run_pc = target;
 341                         return ERROR_OK;
 342                 }
 343                 else
 344                 {
 345                         if (instruction.type == ARM_B)
 346                         {
 347                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target);
 348                         }
 349                         else if (instruction.type == ARM_BL)
 350                         {
 351                                 u32 old_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
 352                                 buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 14).value, 0, 32, old_pc + 4);
 353                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target);
 354                         }
 355                         else if (instruction.type == ARM_BX)
 356                         {
 357                                 if (target & 0x1)
 358                                 {
 359                                         armv4_5->core_state = ARMV4_5_STATE_THUMB;
 360                                 }
 361                                 else
 362                                 {
 363                                         armv4_5->core_state = ARMV4_5_STATE_ARM;
 364                                 }
 365                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target & 0xfffffffe);
 366                         }
 367                         else if (instruction.type == ARM_BLX)
 368                         {
 369                                 u32 old_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
 370                                 buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 14).value, 0, 32, old_pc + 4);
 371
 372                                 if (target & 0x1)
 373                                 {
 374                                         armv4_5->core_state = ARMV4_5_STATE_THUMB;
 375                                 }
 376                                 else
 377                                 {
 378                                         armv4_5->core_state = ARMV4_5_STATE_ARM;
 379                                 }
 380                                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target & 0xfffffffe);
 381                         }
 382
 383                         return ERROR_OK;
 384                 }
 385         }
 386         /* data processing instructions, except compare instructions (CMP, CMN, TST, TEQ) */
 387         else if (((instruction.type >= ARM_AND) && (instruction.type <= ARM_RSC))
 388                         || ((instruction.type >= ARM_ORR) && (instruction.type <= ARM_MVN)))
 389         {
 390                 u32 Rd, Rn, shifter_operand;
 391                 u8 C = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
 392                 u8 carry_out;
 393
 394                 Rd = 0x0;
 395                 Rn = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.data_proc.Rn).value, 0, 32);
 396                 shifter_operand = arm_shifter_operand(armv4_5, instruction.info.data_proc.variant, instruction.info.data_proc.shifter_operand, &carry_out);
 397
 398                 /* adjust Rn in case the PC is being read */
 399                 if (instruction.info.data_proc.Rn == 15)
 400                         Rn += 2 * instruction_size;
 401
 402                 if (instruction.type == ARM_AND)
 403                         Rd = Rn & shifter_operand;
 404                 else if (instruction.type == ARM_EOR)
 405                         Rd = Rn ^ shifter_operand;
 406                 else if (instruction.type == ARM_SUB)
 407                         Rd = Rn - shifter_operand;
 408                 else if (instruction.type == ARM_RSB)
 409                         Rd = shifter_operand - Rn;
 410                 else if (instruction.type == ARM_ADD)
 411                         Rd = Rn + shifter_operand;
 412                 else if (instruction.type == ARM_ADC)
 413                         Rd = Rn + shifter_operand + (C & 1);
 414                 else if (instruction.type == ARM_SBC)
 415                         Rd = Rn - shifter_operand - (C & 1) ? 0 : 1;
 416                 else if (instruction.type == ARM_RSC)
 417                         Rd = shifter_operand - Rn - (C & 1) ? 0 : 1;
 418                 else if (instruction.type == ARM_ORR)
 419                         Rd = Rn | shifter_operand;
 420                 else if (instruction.type == ARM_BIC)
 421                         Rd = Rn & ~(shifter_operand);
 422                 else if (instruction.type == ARM_MOV)
 423                         Rd = shifter_operand;
 424                 else if (instruction.type == ARM_MVN)
 425                         Rd = ~shifter_operand;
 426
 427                 if (dry_run_pc)
 428                 {
 429                         if (instruction.info.data_proc.Rd == 15)
 430                         {
 431                                 *dry_run_pc = Rd;
 432                                 return ERROR_OK;
 433                         }
 434                         else
 435                         {
 436                                 *dry_run_pc = current_pc + instruction_size;
 437                         }
 438
 439                         return ERROR_OK;
 440                 }
 441                 else
 442                 {
 443                         buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.data_proc.Rd).value, 0, 32, Rd);
 444                         WARNING("no updating of flags yet");
 445
 446                         if (instruction.info.data_proc.Rd == 15)
 447                                 return ERROR_OK;
 448                 }
 449         }
 450         /* compare instructions (CMP, CMN, TST, TEQ) */
 451         else if ((instruction.type >= ARM_TST) && (instruction.type <= ARM_CMN))
 452         {
 453                 if (dry_run_pc)
 454                 {
 455                         *dry_run_pc = current_pc + instruction_size;
 456                         return ERROR_OK;
 457                 }
 458                 else
 459                 {
 460                         WARNING("no updating of flags yet");
 461                 }
 462         }
 463         /* load register instructions */
 464         else if ((instruction.type >= ARM_LDR) && (instruction.type <= ARM_LDRSH))
 465         {
 466                 u32 load_address, modified_address, load_value;
 467                 u32 Rn = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store.Rn).value, 0, 32);
 468
 469                 /* adjust Rn in case the PC is being read */
 470                 if (instruction.info.load_store.Rn == 15)
 471                         Rn += 2 * instruction_size;
 472
 473                 if (instruction.info.load_store.offset_mode == 0)
 474                 {
 475                         if (instruction.info.load_store.U)
 476                                 modified_address = Rn + instruction.info.load_store.offset.offset;
 477                         else
 478                                 modified_address = Rn - instruction.info.load_store.offset.offset;
 479                 }
 480                 else if (instruction.info.load_store.offset_mode == 1)
 481                 {
 482                         u32 offset;
 483                         u32 Rm = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store.offset.reg.Rm).value, 0, 32);
 484                         u8 shift = instruction.info.load_store.offset.reg.shift;
 485                         u8 shift_imm = instruction.info.load_store.offset.reg.shift_imm;
 486                         u8 carry = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
 487
 488                         offset = arm_shift(shift, Rm, shift_imm, &carry);
 489
 490                         if (instruction.info.load_store.U)
 491                                 modified_address = Rn + offset;
 492                         else
 493                                 modified_address = Rn - offset;
 494                 }
 495                 else
 496                 {
 497                         ERROR("BUG: offset_mode neither 0 (offset) nor 1 (scaled register)");
 498                 }
 499
 500                 if (instruction.info.load_store.index_mode == 0)
 501                 {
 502                         /* offset mode
 503                          * we load from the modified address, but don't change the base address register */
 504                         load_address = modified_address;
 505                         modified_address = Rn;
 506                 }
 507                 else if (instruction.info.load_store.index_mode == 1)
 508                 {
 509                         /* pre-indexed mode
 510                          * we load from the modified address, and write it back to the base address register */
 511                         load_address = modified_address;
 512                 }
 513                 else if (instruction.info.load_store.index_mode == 2)
 514                 {
 515                         /* post-indexed mode
 516                          * we load from the unmodified address, and write the modified address back */
 517                          load_address = Rn;
 518                 }
 519
 520                 target_read_u32(target, load_address, &load_value);
 521
 522                 if (dry_run_pc)
 523                 {
 524                         if (instruction.info.load_store.Rd == 15)
 525                         {
 526                                 *dry_run_pc = load_value;
 527                                 return ERROR_OK;
 528                         }
 529                         else
 530                         {
 531                                 *dry_run_pc = current_pc + instruction_size;
 532                         }
 533
 534                         return ERROR_OK;
 535                 }
 536                 else
 537                 {
 538                         if ((instruction.info.load_store.index_mode == 1) ||
 539                                 (instruction.info.load_store.index_mode == 2))
 540                         {
 541                                 buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store.Rn).value, 0, 32, modified_address);
 542                         }
 543                         buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store.Rd).value, 0, 32, load_value);
 544
 545                         if (instruction.info.load_store.Rd == 15)
 546                                 return ERROR_OK;
 547                 }
 548         }
 549         /* load multiple instruction */
 550         else if (instruction.type == ARM_LDM)
 551         {
 552                 int i;
 553                 u32 Rn = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store_multiple.Rn).value, 0, 32);
 554                 u32 load_values[16];
 555                 int bits_set = 0;
 556
 557                 for (i = 0; i < 16; i++)
 558                 {
 559                         if (instruction.info.load_store_multiple.register_list & (1 << i))
 560                                 bits_set++;
 561                 }
 562
 563                 switch (instruction.info.load_store_multiple.addressing_mode)
 564                 {
 565                         case 0: /* Increment after */
 566                                 Rn = Rn;
 567                                 break;
 568                         case 1: /* Increment before */
 569                                 Rn = Rn + 4;
 570                                 break;
 571                         case 2: /* Decrement after */
 572                                 Rn = Rn - (bits_set * 4) + 4;
 573                                 break;
 574                         case 3: /* Decrement before */
 575                                 Rn = Rn - (bits_set * 4);
 576                                 break;
 577                 }
 578
 579                 for (i = 0; i < 16; i++)
 580                 {
 581                         if (instruction.info.load_store_multiple.register_list & (1 << i))
 582                         {
 583                                 target_read_u32(target, Rn, &load_values[i]);
 584                                 Rn += 4;
 585                         }
 586                 }
 587
 588                 if (dry_run_pc)
 589                 {
 590                         if (instruction.info.load_store_multiple.register_list & 0x8000)
 591                         {
 592                                 *dry_run_pc = load_values[15];
 593                                 return ERROR_OK;
 594                         }
 595                 }
 596                 else
 597                 {
 598                         enum armv4_5_mode mode = armv4_5->core_mode;
 599                         int update_cpsr = 0;
 600
 601                         if (instruction.info.load_store_multiple.S)
 602                         {
 603                                 if (instruction.info.load_store_multiple.register_list & 0x8000)
 604                                         update_cpsr = 1;
 605                                 else
 606                                         mode = ARMV4_5_MODE_USR;
 607                         }
 608
 609                         for (i = 0; i < 16; i++)
 610                         {
 611                                 if (instruction.info.load_store_multiple.register_list & (1 << i))
 612                                 {
 613                                         buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, mode, i).value, 0, 32, load_values[i]);
 614                                 }
 615                         }
 616
 617                         if (update_cpsr)
 618                         {
 619                                 u32 spsr = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 16).value, 0, 32);
 620                                 buf_set_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32, spsr);
 621                         }
 622
 623                         /* base register writeback */
 624                         if (instruction.info.load_store_multiple.W)
 625                                 buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store_multiple.Rn).value, 0, 32, Rn);
 626
 627                         if (instruction.info.load_store_multiple.register_list & 0x8000)
 628                                 return ERROR_OK;
 629                 }
 630         }
 631         /* store multiple instruction */
 632         else if (instruction.type == ARM_STM)
 633         {
 634                 int i;
 635
 636                 if (dry_run_pc)
 637                 {
 638                         /* STM wont affect PC (advance by instruction size */
 639                 }
 640                 else
 641                 {
 642                         u32 Rn = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store_multiple.Rn).value, 0, 32);
 643                         int bits_set = 0;
 644                         enum armv4_5_mode mode = armv4_5->core_mode;
 645
 646                         for (i = 0; i < 16; i++)
 647                         {
 648                                 if (instruction.info.load_store_multiple.register_list & (1 << i))
 649                                         bits_set++;
 650                         }
 651
 652                         if (instruction.info.load_store_multiple.S)
 653                         {
 654                                 mode = ARMV4_5_MODE_USR;
 655                         }
 656
 657                         switch (instruction.info.load_store_multiple.addressing_mode)
 658                         {
 659                                 case 0: /* Increment after */
 660                                         Rn = Rn;
 661                                         break;
 662                                 case 1: /* Increment before */
 663                                         Rn = Rn + 4;
 664                                         break;
 665                                 case 2: /* Decrement after */
 666                                         Rn = Rn - (bits_set * 4) + 4;
 667                                         break;
 668                                 case 3: /* Decrement before */
 669                                         Rn = Rn - (bits_set * 4);
 670                                         break;
 671                         }
 672
 673                         for (i = 0; i < 16; i++)
 674                         {
 675                                 if (instruction.info.load_store_multiple.register_list & (1 << i))
 676                                 {
 677                                         target_write_u32(target, Rn, buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, i).value, 0, 32));
 678                                         Rn += 4;
 679                                 }
 680                         }
 681
 682                         /* base register writeback */
 683                         if (instruction.info.load_store_multiple.W)
 684                                 buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.load_store_multiple.Rn).value, 0, 32, Rn);
 685
 686                 }
 687         }
 688         else if (!dry_run_pc)
 689         {
 690                 /* the instruction wasn't handled, but we're supposed to simulate it
 691                  */
 692                 return ERROR_ARM_SIMULATOR_NOT_IMPLEMENTED;
 693         }
 694
 695         if (dry_run_pc)
 696         {
 697                 *dry_run_pc = current_pc + instruction_size;
 698                 return ERROR_OK;
 699         }
 700         else
 701         {
 702                 buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
 703                 return ERROR_OK;
 704         }
 705
 706 }