1 /***************************************************************************
2 * Copyright (C) 2006 by Dominic Rath *
3 * Dominic.Rath@gmx.de *
5 * Copyright (C) 2008 by Hongtao Zheng *
8 * This program is free software; you can redistribute it and/or modify *
9 * it under the terms of the GNU General Public License as published by *
10 * the Free Software Foundation; either version 2 of the License, or *
11 * (at your option) any later version. *
13 * This program is distributed in the hope that it will be useful, *
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of *
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
16 * GNU General Public License for more details. *
18 * You should have received a copy of the GNU General Public License *
19 * along with this program; if not, write to the *
20 * Free Software Foundation, Inc., *
21 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
22 ***************************************************************************/
30 #include "arm_disassembler.h"
31 #include "arm_simulator.h"
32 #include <helper/binarybuffer.h>
34 #include <helper/log.h>
36 static uint32_t arm_shift(uint8_t shift, uint32_t Rm,
37 uint32_t shift_amount, uint8_t *carry)
39 uint32_t return_value = 0;
42 if (shift == 0x0) { /* LSL */
43 if ((shift_amount > 0) && (shift_amount <= 32)) {
44 return_value = Rm << shift_amount;
45 *carry = Rm >> (32 - shift_amount);
46 } else if (shift_amount > 32) {
49 } else /* (shift_amount == 0) */
51 } else if (shift == 0x1) { /* LSR */
52 if ((shift_amount > 0) && (shift_amount <= 32)) {
53 return_value = Rm >> shift_amount;
54 *carry = (Rm >> (shift_amount - 1)) & 1;
55 } else if (shift_amount > 32) {
58 } else /* (shift_amount == 0) */
60 } else if (shift == 0x2) { /* ASR */
61 if ((shift_amount > 0) && (shift_amount <= 32)) {
62 /* C right shifts of unsigned values are guaranteed to
63 * be logical (shift in zeroes); simulate an arithmetic
64 * shift (shift in signed-bit) by adding the sign bit
67 return_value = Rm >> shift_amount;
69 return_value |= 0xffffffff << (32 - shift_amount);
70 } else if (shift_amount > 32) {
71 if (Rm & 0x80000000) {
72 return_value = 0xffffffff;
78 } else /* (shift_amount == 0) */
80 } else if (shift == 0x3) { /* ROR */
81 if (shift_amount == 0)
84 shift_amount = shift_amount % 32;
85 return_value = (Rm >> shift_amount) | (Rm << (32 - shift_amount));
86 *carry = (return_value >> 31) & 0x1;
88 } else if (shift == 0x4) { /* RRX */
89 return_value = Rm >> 1;
99 static uint32_t arm_shifter_operand(struct arm_sim_interface *sim,
100 int variant, union arm_shifter_operand shifter_operand,
101 uint8_t *shifter_carry_out)
103 uint32_t return_value;
104 int instruction_size;
106 if (sim->get_state(sim) == ARM_STATE_ARM)
107 instruction_size = 4;
109 instruction_size = 2;
111 *shifter_carry_out = sim->get_cpsr(sim, 29, 1);
113 if (variant == 0) /* 32-bit immediate */
114 return_value = shifter_operand.immediate.immediate;
115 else if (variant == 1) {/* immediate shift */
116 uint32_t Rm = sim->get_reg_mode(sim, shifter_operand.immediate_shift.Rm);
118 /* adjust RM in case the PC is being read */
119 if (shifter_operand.immediate_shift.Rm == 15)
120 Rm += 2 * instruction_size;
122 return_value = arm_shift(shifter_operand.immediate_shift.shift,
123 Rm, shifter_operand.immediate_shift.shift_imm,
125 } else if (variant == 2) { /* register shift */
126 uint32_t Rm = sim->get_reg_mode(sim, shifter_operand.register_shift.Rm);
127 uint32_t Rs = sim->get_reg_mode(sim, shifter_operand.register_shift.Rs);
129 /* adjust RM in case the PC is being read */
130 if (shifter_operand.register_shift.Rm == 15)
131 Rm += 2 * instruction_size;
133 return_value = arm_shift(shifter_operand.immediate_shift.shift,
134 Rm, Rs, shifter_carry_out);
136 LOG_ERROR("BUG: shifter_operand.variant not 0, 1 or 2");
137 return_value = 0xffffffff;
143 static int pass_condition(uint32_t cpsr, uint32_t opcode)
145 switch ((opcode & 0xf0000000) >> 28) {
147 if (cpsr & 0x40000000)
152 if (!(cpsr & 0x40000000))
157 if (cpsr & 0x20000000)
162 if (!(cpsr & 0x20000000))
167 if (cpsr & 0x80000000)
172 if (!(cpsr & 0x80000000))
177 if (cpsr & 0x10000000)
182 if (!(cpsr & 0x10000000))
187 if ((cpsr & 0x20000000) && !(cpsr & 0x40000000))
192 if (!(cpsr & 0x20000000) || (cpsr & 0x40000000))
197 if (((cpsr & 0x80000000) && (cpsr & 0x10000000))
198 || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000)))
203 if (((cpsr & 0x80000000) && !(cpsr & 0x10000000))
204 || (!(cpsr & 0x80000000) && (cpsr & 0x10000000)))
209 if (!(cpsr & 0x40000000) &&
210 (((cpsr & 0x80000000) && (cpsr & 0x10000000))
211 || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000))))
216 if ((cpsr & 0x40000000) ||
217 ((cpsr & 0x80000000) && !(cpsr & 0x10000000))
218 || (!(cpsr & 0x80000000) && (cpsr & 0x10000000)))
228 LOG_ERROR("BUG: should never get here");
232 static int thumb_pass_branch_condition(uint32_t cpsr, uint16_t opcode)
234 return pass_condition(cpsr, (opcode & 0x0f00) << 20);
237 /* simulate a single step (if possible)
238 * if the dry_run_pc argument is provided, no state is changed,
239 * but the new pc is stored in the variable pointed at by the argument
241 static int arm_simulate_step_core(struct target *target,
242 uint32_t *dry_run_pc, struct arm_sim_interface *sim)
244 uint32_t current_pc = sim->get_reg(sim, 15);
245 struct arm_instruction instruction;
246 int instruction_size;
247 int retval = ERROR_OK;
249 if (sim->get_state(sim) == ARM_STATE_ARM) {
252 /* get current instruction, and identify it */
253 retval = target_read_u32(target, current_pc, &opcode);
254 if (retval != ERROR_OK)
256 retval = arm_evaluate_opcode(opcode, current_pc, &instruction);
257 if (retval != ERROR_OK)
259 instruction_size = 4;
261 /* check condition code (for all instructions) */
262 if (!pass_condition(sim->get_cpsr(sim, 0, 32), opcode)) {
264 *dry_run_pc = current_pc + instruction_size;
266 sim->set_reg(sim, 15, current_pc + instruction_size);
273 retval = target_read_u16(target, current_pc, &opcode);
274 if (retval != ERROR_OK)
276 retval = thumb_evaluate_opcode(opcode, current_pc, &instruction);
277 if (retval != ERROR_OK)
279 instruction_size = 2;
281 /* check condition code (only for branch (1) instructions) */
282 if ((opcode & 0xf000) == 0xd000
283 && !thumb_pass_branch_condition(
284 sim->get_cpsr(sim, 0, 32), opcode)) {
286 *dry_run_pc = current_pc + instruction_size;
288 sim->set_reg(sim, 15, current_pc + instruction_size);
293 /* Deal with 32-bit BL/BLX */
294 if ((opcode & 0xf800) == 0xf000) {
295 uint32_t high = instruction.info.b_bl_bx_blx.target_address;
296 retval = target_read_u16(target, current_pc+2, &opcode);
297 if (retval != ERROR_OK)
299 retval = thumb_evaluate_opcode(opcode, current_pc, &instruction);
300 if (retval != ERROR_OK)
302 instruction.info.b_bl_bx_blx.target_address += high;
306 /* examine instruction type */
308 /* branch instructions */
309 if ((instruction.type >= ARM_B) && (instruction.type <= ARM_BLX)) {
310 uint32_t target_address;
312 if (instruction.info.b_bl_bx_blx.reg_operand == -1)
313 target_address = instruction.info.b_bl_bx_blx.target_address;
315 target_address = sim->get_reg_mode(sim,
316 instruction.info.b_bl_bx_blx.reg_operand);
317 if (instruction.info.b_bl_bx_blx.reg_operand == 15)
318 target_address += 2 * instruction_size;
322 *dry_run_pc = target_address & ~1;
325 if (instruction.type == ARM_B)
326 sim->set_reg(sim, 15, target_address);
327 else if (instruction.type == ARM_BL) {
328 uint32_t old_pc = sim->get_reg(sim, 15);
329 int T = (sim->get_state(sim) == ARM_STATE_THUMB);
330 sim->set_reg_mode(sim, 14, old_pc + 4 + T);
331 sim->set_reg(sim, 15, target_address);
332 } else if (instruction.type == ARM_BX) {
333 if (target_address & 0x1)
334 sim->set_state(sim, ARM_STATE_THUMB);
336 sim->set_state(sim, ARM_STATE_ARM);
337 sim->set_reg(sim, 15, target_address & 0xfffffffe);
338 } else if (instruction.type == ARM_BLX) {
339 uint32_t old_pc = sim->get_reg(sim, 15);
340 int T = (sim->get_state(sim) == ARM_STATE_THUMB);
341 sim->set_reg_mode(sim, 14, old_pc + 4 + T);
343 if (target_address & 0x1)
344 sim->set_state(sim, ARM_STATE_THUMB);
346 sim->set_state(sim, ARM_STATE_ARM);
347 sim->set_reg(sim, 15, target_address & 0xfffffffe);
353 /* data processing instructions, except compare instructions (CMP, CMN, TST, TEQ) */
354 else if (((instruction.type >= ARM_AND) && (instruction.type <= ARM_RSC))
355 || ((instruction.type >= ARM_ORR) && (instruction.type <= ARM_MVN))) {
356 uint32_t Rd, Rn, shifter_operand;
357 uint8_t C = sim->get_cpsr(sim, 29, 1);
361 /* ARM_MOV and ARM_MVN does not use Rn */
362 if ((instruction.type != ARM_MOV) && (instruction.type != ARM_MVN))
363 Rn = sim->get_reg_mode(sim, instruction.info.data_proc.Rn);
367 shifter_operand = arm_shifter_operand(sim,
368 instruction.info.data_proc.variant,
369 instruction.info.data_proc.shifter_operand,
372 /* adjust Rn in case the PC is being read */
373 if (instruction.info.data_proc.Rn == 15)
374 Rn += 2 * instruction_size;
376 if (instruction.type == ARM_AND)
377 Rd = Rn & shifter_operand;
378 else if (instruction.type == ARM_EOR)
379 Rd = Rn ^ shifter_operand;
380 else if (instruction.type == ARM_SUB)
381 Rd = Rn - shifter_operand;
382 else if (instruction.type == ARM_RSB)
383 Rd = shifter_operand - Rn;
384 else if (instruction.type == ARM_ADD)
385 Rd = Rn + shifter_operand;
386 else if (instruction.type == ARM_ADC)
387 Rd = Rn + shifter_operand + (C & 1);
388 else if (instruction.type == ARM_SBC)
389 Rd = Rn - shifter_operand - (C & 1) ? 0 : 1;
390 else if (instruction.type == ARM_RSC)
391 Rd = shifter_operand - Rn - (C & 1) ? 0 : 1;
392 else if (instruction.type == ARM_ORR)
393 Rd = Rn | shifter_operand;
394 else if (instruction.type == ARM_BIC)
395 Rd = Rn & ~(shifter_operand);
396 else if (instruction.type == ARM_MOV)
397 Rd = shifter_operand;
398 else if (instruction.type == ARM_MVN)
399 Rd = ~shifter_operand;
401 LOG_WARNING("unhandled instruction type");
404 if (instruction.info.data_proc.Rd == 15)
405 *dry_run_pc = Rd & ~1;
407 *dry_run_pc = current_pc + instruction_size;
411 if (instruction.info.data_proc.Rd == 15) {
412 sim->set_reg_mode(sim, 15, Rd & ~1);
414 sim->set_state(sim, ARM_STATE_THUMB);
416 sim->set_state(sim, ARM_STATE_ARM);
419 sim->set_reg_mode(sim, instruction.info.data_proc.Rd, Rd);
420 LOG_WARNING("no updating of flags yet");
423 /* compare instructions (CMP, CMN, TST, TEQ) */
424 else if ((instruction.type >= ARM_TST) && (instruction.type <= ARM_CMN)) {
426 *dry_run_pc = current_pc + instruction_size;
429 LOG_WARNING("no updating of flags yet");
431 /* load register instructions */
432 else if ((instruction.type >= ARM_LDR) && (instruction.type <= ARM_LDRSH)) {
433 uint32_t load_address = 0, modified_address = 0, load_value = 0;
434 uint32_t Rn = sim->get_reg_mode(sim, instruction.info.load_store.Rn);
436 /* adjust Rn in case the PC is being read */
437 if (instruction.info.load_store.Rn == 15)
438 Rn += 2 * instruction_size;
440 if (instruction.info.load_store.offset_mode == 0) {
441 if (instruction.info.load_store.U)
442 modified_address = Rn + instruction.info.load_store.offset.offset;
444 modified_address = Rn - instruction.info.load_store.offset.offset;
445 } else if (instruction.info.load_store.offset_mode == 1) {
447 uint32_t Rm = sim->get_reg_mode(sim,
448 instruction.info.load_store.offset.reg.Rm);
449 uint8_t shift = instruction.info.load_store.offset.reg.shift;
450 uint8_t shift_imm = instruction.info.load_store.offset.reg.shift_imm;
451 uint8_t carry = sim->get_cpsr(sim, 29, 1);
453 offset = arm_shift(shift, Rm, shift_imm, &carry);
455 if (instruction.info.load_store.U)
456 modified_address = Rn + offset;
458 modified_address = Rn - offset;
460 LOG_ERROR("BUG: offset_mode neither 0 (offset) nor 1 (scaled register)");
462 if (instruction.info.load_store.index_mode == 0) {
464 * we load from the modified address, but don't change
465 * the base address register
467 load_address = modified_address;
468 modified_address = Rn;
469 } else if (instruction.info.load_store.index_mode == 1) {
471 * we load from the modified address, and write it
472 * back to the base address register
474 load_address = modified_address;
475 } else if (instruction.info.load_store.index_mode == 2) {
477 * we load from the unmodified address, and write the
478 * modified address back
483 if ((!dry_run_pc) || (instruction.info.load_store.Rd == 15)) {
484 retval = target_read_u32(target, load_address, &load_value);
485 if (retval != ERROR_OK)
490 if (instruction.info.load_store.Rd == 15)
491 *dry_run_pc = load_value & ~1;
493 *dry_run_pc = current_pc + instruction_size;
496 if ((instruction.info.load_store.index_mode == 1) ||
497 (instruction.info.load_store.index_mode == 2))
498 sim->set_reg_mode(sim,
499 instruction.info.load_store.Rn,
502 if (instruction.info.load_store.Rd == 15) {
503 sim->set_reg_mode(sim, 15, load_value & ~1);
505 sim->set_state(sim, ARM_STATE_THUMB);
507 sim->set_state(sim, ARM_STATE_ARM);
510 sim->set_reg_mode(sim, instruction.info.load_store.Rd, load_value);
513 /* load multiple instruction */
514 else if (instruction.type == ARM_LDM) {
516 uint32_t Rn = sim->get_reg_mode(sim, instruction.info.load_store_multiple.Rn);
517 uint32_t load_values[16];
520 for (i = 0; i < 16; i++) {
521 if (instruction.info.load_store_multiple.register_list & (1 << i))
525 switch (instruction.info.load_store_multiple.addressing_mode) {
526 case 0: /* Increment after */
529 case 1: /* Increment before */
532 case 2: /* Decrement after */
533 Rn = Rn - (bits_set * 4) + 4;
535 case 3: /* Decrement before */
536 Rn = Rn - (bits_set * 4);
540 for (i = 0; i < 16; i++) {
541 if (instruction.info.load_store_multiple.register_list & (1 << i)) {
542 if ((!dry_run_pc) || (i == 15))
543 target_read_u32(target, Rn, &load_values[i]);
549 if (instruction.info.load_store_multiple.register_list & 0x8000) {
550 *dry_run_pc = load_values[15] & ~1;
556 if (instruction.info.load_store_multiple.S) {
557 if (instruction.info.load_store_multiple.register_list & 0x8000)
561 for (i = 0; i < 16; i++) {
562 if (instruction.info.load_store_multiple.register_list & (1 << i)) {
564 uint32_t val = load_values[i];
565 sim->set_reg_mode(sim, i, val & ~1);
567 sim->set_state(sim, ARM_STATE_THUMB);
569 sim->set_state(sim, ARM_STATE_ARM);
571 sim->set_reg_mode(sim, i, load_values[i]);
576 uint32_t spsr = sim->get_reg_mode(sim, 16);
577 sim->set_reg(sim, ARMV4_5_CPSR, spsr);
580 /* base register writeback */
581 if (instruction.info.load_store_multiple.W)
582 sim->set_reg_mode(sim, instruction.info.load_store_multiple.Rn, Rn);
585 if (instruction.info.load_store_multiple.register_list & 0x8000)
589 /* store multiple instruction */
590 else if (instruction.type == ARM_STM) {
594 /* STM wont affect PC (advance by instruction size */
596 uint32_t Rn = sim->get_reg_mode(sim,
597 instruction.info.load_store_multiple.Rn);
600 for (i = 0; i < 16; i++) {
601 if (instruction.info.load_store_multiple.register_list & (1 << i))
605 switch (instruction.info.load_store_multiple.addressing_mode) {
606 case 0: /* Increment after */
609 case 1: /* Increment before */
612 case 2: /* Decrement after */
613 Rn = Rn - (bits_set * 4) + 4;
615 case 3: /* Decrement before */
616 Rn = Rn - (bits_set * 4);
620 for (i = 0; i < 16; i++) {
621 if (instruction.info.load_store_multiple.register_list & (1 << i)) {
622 target_write_u32(target, Rn, sim->get_reg_mode(sim, i));
627 /* base register writeback */
628 if (instruction.info.load_store_multiple.W)
629 sim->set_reg_mode(sim,
630 instruction.info.load_store_multiple.Rn, Rn);
633 } else if (!dry_run_pc) {
634 /* the instruction wasn't handled, but we're supposed to simulate it
636 LOG_ERROR("Unimplemented instruction, could not simulate it.");
641 *dry_run_pc = current_pc + instruction_size;
644 sim->set_reg(sim, 15, current_pc + instruction_size);
650 static uint32_t armv4_5_get_reg(struct arm_sim_interface *sim, int reg)
652 struct arm *arm = (struct arm *)sim->user_data;
654 return buf_get_u32(arm->core_cache->reg_list[reg].value, 0, 32);
657 static void armv4_5_set_reg(struct arm_sim_interface *sim, int reg, uint32_t value)
659 struct arm *arm = (struct arm *)sim->user_data;
661 buf_set_u32(arm->core_cache->reg_list[reg].value, 0, 32, value);
664 static uint32_t armv4_5_get_reg_mode(struct arm_sim_interface *sim, int reg)
666 struct arm *arm = (struct arm *)sim->user_data;
668 return buf_get_u32(ARMV4_5_CORE_REG_MODE(arm->core_cache,
669 arm->core_mode, reg).value, 0, 32);
672 static void armv4_5_set_reg_mode(struct arm_sim_interface *sim, int reg, uint32_t value)
674 struct arm *arm = (struct arm *)sim->user_data;
676 buf_set_u32(ARMV4_5_CORE_REG_MODE(arm->core_cache,
677 arm->core_mode, reg).value, 0, 32, value);
680 static uint32_t armv4_5_get_cpsr(struct arm_sim_interface *sim, int pos, int bits)
682 struct arm *arm = (struct arm *)sim->user_data;
684 return buf_get_u32(arm->cpsr->value, pos, bits);
687 static enum arm_state armv4_5_get_state(struct arm_sim_interface *sim)
689 struct arm *arm = (struct arm *)sim->user_data;
691 return arm->core_state;
694 static void armv4_5_set_state(struct arm_sim_interface *sim, enum arm_state mode)
696 struct arm *arm = (struct arm *)sim->user_data;
698 arm->core_state = mode;
701 static enum arm_mode armv4_5_get_mode(struct arm_sim_interface *sim)
703 struct arm *arm = (struct arm *)sim->user_data;
705 return arm->core_mode;
708 int arm_simulate_step(struct target *target, uint32_t *dry_run_pc)
710 struct arm *arm = target_to_arm(target);
711 struct arm_sim_interface sim;
714 sim.get_reg = &armv4_5_get_reg;
715 sim.set_reg = &armv4_5_set_reg;
716 sim.get_reg_mode = &armv4_5_get_reg_mode;
717 sim.set_reg_mode = &armv4_5_set_reg_mode;
718 sim.get_cpsr = &armv4_5_get_cpsr;
719 sim.get_mode = &armv4_5_get_mode;
720 sim.get_state = &armv4_5_get_state;
721 sim.set_state = &armv4_5_set_state;
723 return arm_simulate_step_core(target, dry_run_pc, &sim);