/*************************************************************************** * Copyright (C) 2006 by Dominic Rath * * Dominic.Rath@gmx.de * * * * Copyright (C) 2008 by Hongtao Zheng * * hontor@126.com * * * * This program is free software; you can redistribute it and/or modify * * it under the terms of the GNU General Public License as published by * * the Free Software Foundation; either version 2 of the License, or * * (at your option) any later version. * * * * This program is distributed in the hope that it will be useful, * * but WITHOUT ANY WARRANTY; without even the implied warranty of * * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * * GNU General Public License for more details. * * * * You should have received a copy of the GNU General Public License * * along with this program; if not, write to the * * Free Software Foundation, Inc., * * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * ***************************************************************************/ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "armv4_5.h" #include "arm_disassembler.h" #include "arm_simulator.h" #include "binarybuffer.h" #include "register.h" #include "log.h" static uint32_t arm_shift(uint8_t shift, uint32_t Rm, uint32_t shift_amount, uint8_t *carry) { uint32_t return_value = 0; shift_amount &= 0xff; if (shift == 0x0) /* LSL */ { if ((shift_amount > 0) && (shift_amount <= 32)) { return_value = Rm << shift_amount; *carry = Rm >> (32 - shift_amount); } else if (shift_amount > 32) { return_value = 0x0; *carry = 0x0; } else /* (shift_amount == 0) */ { return_value = Rm; } } else if (shift == 0x1) /* LSR */ { if ((shift_amount > 0) && (shift_amount <= 32)) { return_value = Rm >> shift_amount; *carry = (Rm >> (shift_amount - 1)) & 1; } else if (shift_amount > 32) { return_value = 0x0; *carry = 0x0; } else /* (shift_amount == 0) */ { return_value = Rm; } } else if (shift == 0x2) /* ASR */ { if ((shift_amount > 0) && (shift_amount <= 32)) { /* C right shifts of unsigned values are guaranteed to * be logical (shift in zeroes); simulate an arithmetic * shift (shift in signed-bit) by adding the sign bit * manually */ return_value = Rm >> shift_amount; if (Rm & 0x80000000) return_value |= 0xffffffff << (32 - shift_amount); } else if (shift_amount > 32) { if (Rm & 0x80000000) { return_value = 0xffffffff; *carry = 0x1; } else { return_value = 0x0; *carry = 0x0; } } else /* (shift_amount == 0) */ { return_value = Rm; } } else if (shift == 0x3) /* ROR */ { if (shift_amount == 0) { return_value = Rm; } else { shift_amount = shift_amount % 32; return_value = (Rm >> shift_amount) | (Rm << (32 - shift_amount)); *carry = (return_value >> 31) & 0x1; } } else if (shift == 0x4) /* RRX */ { return_value = Rm >> 1; if (*carry) Rm |= 0x80000000; *carry = Rm & 0x1; } return return_value; } static uint32_t arm_shifter_operand(struct arm_sim_interface *sim, int variant, union arm_shifter_operand shifter_operand, uint8_t *shifter_carry_out) { uint32_t return_value; int instruction_size; if (sim->get_state(sim) == ARMV4_5_STATE_ARM) instruction_size = 4; else instruction_size = 2; *shifter_carry_out = sim->get_cpsr(sim, 29, 1); if (variant == 0) /* 32-bit immediate */ { return_value = shifter_operand.immediate.immediate; } else if (variant == 1) /* immediate shift */ { uint32_t Rm = sim->get_reg_mode(sim, shifter_operand.immediate_shift.Rm); /* adjust RM in case the PC is being read */ if (shifter_operand.immediate_shift.Rm == 15) Rm += 2 * instruction_size; return_value = arm_shift(shifter_operand.immediate_shift.shift, Rm, shifter_operand.immediate_shift.shift_imm, shifter_carry_out); } else if (variant == 2) /* register shift */ { uint32_t Rm = sim->get_reg_mode(sim, shifter_operand.register_shift.Rm); uint32_t Rs = sim->get_reg_mode(sim, shifter_operand.register_shift.Rs); /* adjust RM in case the PC is being read */ if (shifter_operand.register_shift.Rm == 15) Rm += 2 * instruction_size; return_value = arm_shift(shifter_operand.immediate_shift.shift, Rm, Rs, shifter_carry_out); } else { LOG_ERROR("BUG: shifter_operand.variant not 0, 1 or 2"); return_value = 0xffffffff; } return return_value; } static int pass_condition(uint32_t cpsr, uint32_t opcode) { switch ((opcode & 0xf0000000) >> 28) { case 0x0: /* EQ */ if (cpsr & 0x40000000) return 1; else return 0; case 0x1: /* NE */ if (!(cpsr & 0x40000000)) return 1; else return 0; case 0x2: /* CS */ if (cpsr & 0x20000000) return 1; else return 0; case 0x3: /* CC */ if (!(cpsr & 0x20000000)) return 1; else return 0; case 0x4: /* MI */ if (cpsr & 0x80000000) return 1; else return 0; case 0x5: /* PL */ if (!(cpsr & 0x80000000)) return 1; else return 0; case 0x6: /* VS */ if (cpsr & 0x10000000) return 1; else return 0; case 0x7: /* VC */ if (!(cpsr & 0x10000000)) return 1; else return 0; case 0x8: /* HI */ if ((cpsr & 0x20000000) && !(cpsr & 0x40000000)) return 1; else return 0; case 0x9: /* LS */ if (!(cpsr & 0x20000000) || (cpsr & 0x40000000)) return 1; else return 0; case 0xa: /* GE */ if (((cpsr & 0x80000000) && (cpsr & 0x10000000)) || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000))) return 1; else return 0; case 0xb: /* LT */ if (((cpsr & 0x80000000) && !(cpsr & 0x10000000)) || (!(cpsr & 0x80000000) && (cpsr & 0x10000000))) return 1; else return 0; case 0xc: /* GT */ if (!(cpsr & 0x40000000) && (((cpsr & 0x80000000) && (cpsr & 0x10000000)) || (!(cpsr & 0x80000000) && !(cpsr & 0x10000000)))) return 1; else return 0; case 0xd: /* LE */ if ((cpsr & 0x40000000) || ((cpsr & 0x80000000) && !(cpsr & 0x10000000)) || (!(cpsr & 0x80000000) && (cpsr & 0x10000000))) return 1; else return 0; case 0xe: case 0xf: return 1; } LOG_ERROR("BUG: should never get here"); return 0; } static int thumb_pass_branch_condition(uint32_t cpsr, uint16_t opcode) { return pass_condition(cpsr, (opcode & 0x0f00) << 20); } /* simulate a single step (if possible) * if the dry_run_pc argument is provided, no state is changed, * but the new pc is stored in the variable pointed at by the argument */ int arm_simulate_step_core(struct target *target, uint32_t *dry_run_pc, struct arm_sim_interface *sim) { uint32_t current_pc = sim->get_reg(sim, 15); struct arm_instruction instruction; int instruction_size; int retval = ERROR_OK; if (sim->get_state(sim) == ARMV4_5_STATE_ARM) { uint32_t opcode; /* get current instruction, and identify it */ if ((retval = target_read_u32(target, current_pc, &opcode)) != ERROR_OK) { return retval; } if ((retval = arm_evaluate_opcode(opcode, current_pc, &instruction)) != ERROR_OK) { return retval; } instruction_size = 4; /* check condition code (for all instructions) */ if (!pass_condition(sim->get_cpsr(sim, 0, 32), opcode)) { if (dry_run_pc) { *dry_run_pc = current_pc + instruction_size; } else { sim->set_reg(sim, 15, current_pc + instruction_size); } return ERROR_OK; } } else { uint16_t opcode; retval = target_read_u16(target, current_pc, &opcode); if (retval != ERROR_OK) return retval; retval = thumb_evaluate_opcode(opcode, current_pc, &instruction); if (retval != ERROR_OK) return retval; instruction_size = 2; /* check condition code (only for branch (1) instructions) */ if ((opcode & 0xf000) == 0xd000 && !thumb_pass_branch_condition( sim->get_cpsr(sim, 0, 32), opcode)) { if (dry_run_pc) { *dry_run_pc = current_pc + instruction_size; } else { sim->set_reg(sim, 15, current_pc + instruction_size); } return ERROR_OK; } /* Deal with 32-bit BL/BLX */ if ((opcode & 0xf800) == 0xf000) { uint32_t high = instruction.info.b_bl_bx_blx.target_address; retval = target_read_u16(target, current_pc+2, &opcode); if (retval != ERROR_OK) return retval; retval = thumb_evaluate_opcode(opcode, current_pc, &instruction); if (retval != ERROR_OK) return retval; instruction.info.b_bl_bx_blx.target_address += high; } } /* examine instruction type */ /* branch instructions */ if ((instruction.type >= ARM_B) && (instruction.type <= ARM_BLX)) { uint32_t target; if (instruction.info.b_bl_bx_blx.reg_operand == -1) { target = instruction.info.b_bl_bx_blx.target_address; } else { target = sim->get_reg_mode(sim, instruction.info.b_bl_bx_blx.reg_operand); if (instruction.info.b_bl_bx_blx.reg_operand == 15) { target += 2 * instruction_size; } } if (dry_run_pc) { *dry_run_pc = target & ~1; return ERROR_OK; } else { if (instruction.type == ARM_B) { sim->set_reg(sim, 15, target); } else if (instruction.type == ARM_BL) { uint32_t old_pc = sim->get_reg(sim, 15); int T = (sim->get_state(sim) == ARMV4_5_STATE_THUMB); sim->set_reg_mode(sim, 14, old_pc + 4 + T); sim->set_reg(sim, 15, target); } else if (instruction.type == ARM_BX) { if (target & 0x1) { sim->set_state(sim, ARMV4_5_STATE_THUMB); } else { sim->set_state(sim, ARMV4_5_STATE_ARM); } sim->set_reg(sim, 15, target & 0xfffffffe); } else if (instruction.type == ARM_BLX) { uint32_t old_pc = sim->get_reg(sim, 15); int T = (sim->get_state(sim) == ARMV4_5_STATE_THUMB); sim->set_reg_mode(sim, 14, old_pc + 4 + T); if (target & 0x1) { sim->set_state(sim, ARMV4_5_STATE_THUMB); } else { sim->set_state(sim, ARMV4_5_STATE_ARM); } sim->set_reg(sim, 15, target & 0xfffffffe); } return ERROR_OK; } } /* data processing instructions, except compare instructions (CMP, CMN, TST, TEQ) */ else if (((instruction.type >= ARM_AND) && (instruction.type <= ARM_RSC)) || ((instruction.type >= ARM_ORR) && (instruction.type <= ARM_MVN))) { uint32_t Rd, Rn, shifter_operand; uint8_t C = sim->get_cpsr(sim, 29, 1); uint8_t carry_out; Rd = 0x0; /* ARM_MOV and ARM_MVN does not use Rn */ if ((instruction.type != ARM_MOV) && (instruction.type != ARM_MVN)) Rn = sim->get_reg_mode(sim, instruction.info.data_proc.Rn); else Rn = 0; shifter_operand = arm_shifter_operand(sim, instruction.info.data_proc.variant, instruction.info.data_proc.shifter_operand, &carry_out); /* adjust Rn in case the PC is being read */ if (instruction.info.data_proc.Rn == 15) Rn += 2 * instruction_size; if (instruction.type == ARM_AND) Rd = Rn & shifter_operand; else if (instruction.type == ARM_EOR) Rd = Rn ^ shifter_operand; else if (instruction.type == ARM_SUB) Rd = Rn - shifter_operand; else if (instruction.type == ARM_RSB) Rd = shifter_operand - Rn; else if (instruction.type == ARM_ADD) Rd = Rn + shifter_operand; else if (instruction.type == ARM_ADC) Rd = Rn + shifter_operand + (C & 1); else if (instruction.type == ARM_SBC) Rd = Rn - shifter_operand - (C & 1) ? 0 : 1; else if (instruction.type == ARM_RSC) Rd = shifter_operand - Rn - (C & 1) ? 0 : 1; else if (instruction.type == ARM_ORR) Rd = Rn | shifter_operand; else if (instruction.type == ARM_BIC) Rd = Rn & ~(shifter_operand); else if (instruction.type == ARM_MOV) Rd = shifter_operand; else if (instruction.type == ARM_MVN) Rd = ~shifter_operand; else LOG_WARNING("unhandled instruction type"); if (dry_run_pc) { if (instruction.info.data_proc.Rd == 15) *dry_run_pc = Rd & ~1; else *dry_run_pc = current_pc + instruction_size; return ERROR_OK; } else { if (instruction.info.data_proc.Rd == 15) { sim->set_reg_mode(sim, 15, Rd & ~1); if (Rd & 1) sim->set_state(sim, ARMV4_5_STATE_THUMB); else sim->set_state(sim, ARMV4_5_STATE_ARM); return ERROR_OK; } sim->set_reg_mode(sim, instruction.info.data_proc.Rd, Rd); LOG_WARNING("no updating of flags yet"); } } /* compare instructions (CMP, CMN, TST, TEQ) */ else if ((instruction.type >= ARM_TST) && (instruction.type <= ARM_CMN)) { if (dry_run_pc) { *dry_run_pc = current_pc + instruction_size; return ERROR_OK; } else { LOG_WARNING("no updating of flags yet"); } } /* load register instructions */ else if ((instruction.type >= ARM_LDR) && (instruction.type <= ARM_LDRSH)) { uint32_t load_address = 0, modified_address = 0, load_value; uint32_t Rn = sim->get_reg_mode(sim, instruction.info.load_store.Rn); /* adjust Rn in case the PC is being read */ if (instruction.info.load_store.Rn == 15) Rn += 2 * instruction_size; if (instruction.info.load_store.offset_mode == 0) { if (instruction.info.load_store.U) modified_address = Rn + instruction.info.load_store.offset.offset; else modified_address = Rn - instruction.info.load_store.offset.offset; } else if (instruction.info.load_store.offset_mode == 1) { uint32_t offset; uint32_t Rm = sim->get_reg_mode(sim, instruction.info.load_store.offset.reg.Rm); uint8_t shift = instruction.info.load_store.offset.reg.shift; uint8_t shift_imm = instruction.info.load_store.offset.reg.shift_imm; uint8_t carry = sim->get_cpsr(sim, 29, 1); offset = arm_shift(shift, Rm, shift_imm, &carry); if (instruction.info.load_store.U) modified_address = Rn + offset; else modified_address = Rn - offset; } else { LOG_ERROR("BUG: offset_mode neither 0 (offset) nor 1 (scaled register)"); } if (instruction.info.load_store.index_mode == 0) { /* offset mode * we load from the modified address, but don't change * the base address register */ load_address = modified_address; modified_address = Rn; } else if (instruction.info.load_store.index_mode == 1) { /* pre-indexed mode * we load from the modified address, and write it * back to the base address register */ load_address = modified_address; } else if (instruction.info.load_store.index_mode == 2) { /* post-indexed mode * we load from the unmodified address, and write the * modified address back */ load_address = Rn; } if ((!dry_run_pc) || (instruction.info.load_store.Rd == 15)) { retval = target_read_u32(target, load_address, &load_value); if (retval != ERROR_OK) return retval; } if (dry_run_pc) { if (instruction.info.load_store.Rd == 15) *dry_run_pc = load_value & ~1; else *dry_run_pc = current_pc + instruction_size; return ERROR_OK; } else { if ((instruction.info.load_store.index_mode == 1) || (instruction.info.load_store.index_mode == 2)) { sim->set_reg_mode(sim, instruction.info.load_store.Rn, modified_address); } if (instruction.info.load_store.Rd == 15) { sim->set_reg_mode(sim, 15, load_value & ~1); if (load_value & 1) sim->set_state(sim, ARMV4_5_STATE_THUMB); else sim->set_state(sim, ARMV4_5_STATE_ARM); return ERROR_OK; } sim->set_reg_mode(sim, instruction.info.load_store.Rd, load_value); } } /* load multiple instruction */ else if (instruction.type == ARM_LDM) { int i; uint32_t Rn = sim->get_reg_mode(sim, instruction.info.load_store_multiple.Rn); uint32_t load_values[16]; int bits_set = 0; for (i = 0; i < 16; i++) { if (instruction.info.load_store_multiple.register_list & (1 << i)) bits_set++; } switch (instruction.info.load_store_multiple.addressing_mode) { case 0: /* Increment after */ Rn = Rn; break; case 1: /* Increment before */ Rn = Rn + 4; break; case 2: /* Decrement after */ Rn = Rn - (bits_set * 4) + 4; break; case 3: /* Decrement before */ Rn = Rn - (bits_set * 4); break; } for (i = 0; i < 16; i++) { if (instruction.info.load_store_multiple.register_list & (1 << i)) { if ((!dry_run_pc) || (i == 15)) { target_read_u32(target, Rn, &load_values[i]); } Rn += 4; } } if (dry_run_pc) { if (instruction.info.load_store_multiple.register_list & 0x8000) { *dry_run_pc = load_values[15] & ~1; return ERROR_OK; } } else { enum armv4_5_mode mode = sim->get_mode(sim); int update_cpsr = 0; if (instruction.info.load_store_multiple.S) { if (instruction.info.load_store_multiple.register_list & 0x8000) update_cpsr = 1; else mode = ARMV4_5_MODE_USR; } for (i = 0; i < 16; i++) { if (instruction.info.load_store_multiple.register_list & (1 << i)) { if (i == 15) { uint32_t val = load_values[i]; sim->set_reg_mode(sim, i, val & ~1); if (val & 1) sim->set_state(sim, ARMV4_5_STATE_THUMB); else sim->set_state(sim, ARMV4_5_STATE_ARM); } else { sim->set_reg_mode(sim, i, load_values[i]); } } } if (update_cpsr) { uint32_t spsr = sim->get_reg_mode(sim, 16); sim->set_reg(sim, ARMV4_5_CPSR, spsr); } /* base register writeback */ if (instruction.info.load_store_multiple.W) sim->set_reg_mode(sim, instruction.info.load_store_multiple.Rn, Rn); if (instruction.info.load_store_multiple.register_list & 0x8000) return ERROR_OK; } } /* store multiple instruction */ else if (instruction.type == ARM_STM) { int i; if (dry_run_pc) { /* STM wont affect PC (advance by instruction size */ } else { uint32_t Rn = sim->get_reg_mode(sim, instruction.info.load_store_multiple.Rn); int bits_set = 0; enum armv4_5_mode mode = sim->get_mode(sim); for (i = 0; i < 16; i++) { if (instruction.info.load_store_multiple.register_list & (1 << i)) bits_set++; } if (instruction.info.load_store_multiple.S) { mode = ARMV4_5_MODE_USR; } switch (instruction.info.load_store_multiple.addressing_mode) { case 0: /* Increment after */ Rn = Rn; break; case 1: /* Increment before */ Rn = Rn + 4; break; case 2: /* Decrement after */ Rn = Rn - (bits_set * 4) + 4; break; case 3: /* Decrement before */ Rn = Rn - (bits_set * 4); break; } for (i = 0; i < 16; i++) { if (instruction.info.load_store_multiple.register_list & (1 << i)) { target_write_u32(target, Rn, sim->get_reg_mode(sim, i)); Rn += 4; } } /* base register writeback */ if (instruction.info.load_store_multiple.W) sim->set_reg_mode(sim, instruction.info.load_store_multiple.Rn, Rn); } } else if (!dry_run_pc) { /* the instruction wasn't handled, but we're supposed to simulate it */ LOG_ERROR("Unimplemented instruction, could not simulate it."); return ERROR_FAIL; } if (dry_run_pc) { *dry_run_pc = current_pc + instruction_size; return ERROR_OK; } else { sim->set_reg(sim, 15, current_pc + instruction_size); return ERROR_OK; } } static uint32_t armv4_5_get_reg(struct arm_sim_interface *sim, int reg) { struct arm *armv4_5 = (struct arm *)sim->user_data; return buf_get_u32(armv4_5->core_cache->reg_list[reg].value, 0, 32); } static void armv4_5_set_reg(struct arm_sim_interface *sim, int reg, uint32_t value) { struct arm *armv4_5 = (struct arm *)sim->user_data; buf_set_u32(armv4_5->core_cache->reg_list[reg].value, 0, 32, value); } static uint32_t armv4_5_get_reg_mode(struct arm_sim_interface *sim, int reg) { struct arm *armv4_5 = (struct arm *)sim->user_data; return buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, reg).value, 0, 32); } static void armv4_5_set_reg_mode(struct arm_sim_interface *sim, int reg, uint32_t value) { struct arm *armv4_5 = (struct arm *)sim->user_data; buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, reg).value, 0, 32, value); } static uint32_t armv4_5_get_cpsr(struct arm_sim_interface *sim, int pos, int bits) { struct arm *armv4_5 = (struct arm *)sim->user_data; return buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, pos, bits); } static enum armv4_5_state armv4_5_get_state(struct arm_sim_interface *sim) { struct arm *armv4_5 = (struct arm *)sim->user_data; return armv4_5->core_state; } static void armv4_5_set_state(struct arm_sim_interface *sim, enum armv4_5_state mode) { struct arm *armv4_5 = (struct arm *)sim->user_data; armv4_5->core_state = mode; } static enum armv4_5_mode armv4_5_get_mode(struct arm_sim_interface *sim) { struct arm *armv4_5 = (struct arm *)sim->user_data; return armv4_5->core_mode; } int arm_simulate_step(struct target *target, uint32_t *dry_run_pc) { struct armv4_5_common_s *armv4_5 = target_to_armv4_5(target); struct arm_sim_interface sim; sim.user_data = armv4_5; sim.get_reg = &armv4_5_get_reg; sim.set_reg = &armv4_5_set_reg; sim.get_reg_mode = &armv4_5_get_reg_mode; sim.set_reg_mode = &armv4_5_set_reg_mode; sim.get_cpsr = &armv4_5_get_cpsr; sim.get_mode = &armv4_5_get_mode; sim.get_state = &armv4_5_get_state; sim.set_state = &armv4_5_set_state; return arm_simulate_step_core(target, dry_run_pc, &sim); }