Revert "target: remove unused working area 'user' field"
[fw/openocd] / src / target / arm_simulator.c
index b21ea4a8865cf5b15c210e5a4f03141dd481c2bb..9ddc85be06a67339110c0de986151e85d9159af5 100644 (file)
  *   Free Software Foundation, Inc.,                                       *
  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  ***************************************************************************/
+
 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif
 
-#include "target.h"
+#include "arm.h"
 #include "armv4_5.h"
 #include "arm_disassembler.h"
 #include "arm_simulator.h"
-#include "log.h"
-#include "binarybuffer.h"
-
-#include <string.h>
+#include <helper/binarybuffer.h>
+#include "register.h"
+#include <helper/log.h>
 
-u32 arm_shift(u8 shift, u32 Rm, u32 shift_amount, u8 *carry)
+static uint32_t arm_shift(uint8_t shift, uint32_t Rm,
+       uint32_t shift_amount, uint8_t *carry)
 {
-       u32 return_value = 0;
+       uint32_t return_value = 0;
        shift_amount &= 0xff;
-       
-       if (shift == 0x0) /* LSL */
-       {
-               if ((shift_amount > 0) && (shift_amount <= 32))
-               {
+
+       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)
-               {
+               } else if (shift_amount > 32) {
                        return_value = 0x0;
                        *carry = 0x0;
-               }
-               else /* (shift_amount == 0) */
-               {
+               } else /* (shift_amount == 0) */
                        return_value = Rm;
-               }
-       }
-       else if (shift == 0x1) /* LSR */
-       {
-               if ((shift_amount > 0) && (shift_amount <= 32))
-               {
+       } 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)
-               {
+               } else if (shift_amount > 32) {
                        return_value = 0x0;
                        *carry = 0x0;
-               }
-               else /* (shift_amount == 0) */
-               {
+               } else /* (shift_amount == 0) */
                        return_value = Rm;
-               }
-       }
-       else if (shift == 0x2) /* ASR */
-       {
-               if ((shift_amount > 0) && (shift_amount <= 32))
-               {
-                       /* right shifts of unsigned values are guaranteed to be logical (shift in zeroes)
-                        * simulate an arithmetic shift (shift in signed-bit) by adding the signed-bit manually */
+       } 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)
-                       {
+               } else if (shift_amount > 32) {
+                       if (Rm & 0x80000000) {
                                return_value = 0xffffffff;
                                *carry = 0x1;
-                       }
-                       else
-                       {
+                       } else {
                                return_value = 0x0;
                                *carry = 0x0;
                        }
-               }
-               else /* (shift_amount == 0) */
-               {
+               } else /* (shift_amount == 0) */
                        return_value = Rm;
-               }
-       }
-       else if (shift == 0x3) /* ROR */
-       {
+       } else if (shift == 0x3) {      /* ROR */
                if (shift_amount == 0)
-               {
                        return_value = Rm;
-               }
-               else
-               {
+               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 */
-       {
+       } else if (shift == 0x4) {      /* RRX */
                return_value = Rm >> 1;
                if (*carry)
                        Rm |= 0x80000000;
                *carry = Rm & 0x1;
        }
-       
+
        return return_value;
 }
 
-u32 arm_shifter_operand(armv4_5_common_t *armv4_5, int variant, union arm_shifter_operand shifter_operand, u8 *shifter_carry_out)
+
+static uint32_t arm_shifter_operand(struct arm_sim_interface *sim,
+       int variant, union arm_shifter_operand shifter_operand,
+       uint8_t *shifter_carry_out)
 {
-       u32 return_value;
+       uint32_t return_value;
        int instruction_size;
-       
-       if (armv4_5->core_state == ARMV4_5_STATE_ARM)
+
+       if (sim->get_state(sim) == ARM_STATE_ARM)
                instruction_size = 4;
        else
                instruction_size = 2;
-       
-       *shifter_carry_out = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
-       
+
+       *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 */
-       {
-               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);
-               
+       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 */
-       {
-               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);
-               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);
-               
+
+               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
-       {
+
+               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;
 }
 
-int pass_condition(u32 cpsr, u32 opcode)
+static int pass_condition(uint32_t cpsr, uint32_t opcode)
 {
-       switch ((opcode & 0xf0000000) >> 28)
-       {
+       switch ((opcode & 0xf0000000) >> 28) {
                case 0x0:       /* EQ */
                        if (cpsr & 0x40000000)
                                return 1;
@@ -244,189 +213,166 @@ int pass_condition(u32 cpsr, u32 opcode)
                        else
                                return 0;
                case 0xd:       /* LE */
-                       if ((cpsr & 0x40000000) &&
-                               (((cpsr & 0x80000000) && !(cpsr & 0x10000000))
-                               || (!(cpsr & 0x80000000) && (cpsr & 0x10000000))))
+                       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;
 }
 
-int thumb_pass_branch_condition(u32 cpsr, u16 opcode)
+static int thumb_pass_branch_condition(uint32_t cpsr, uint16_t opcode)
 {
-       return pass_condition(cpsr, (opcode & 0x0f00) << 20); 
+       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(target_t *target, u32 *dry_run_pc)
+static int arm_simulate_step_core(struct target *target,
+       uint32_t *dry_run_pc, struct arm_sim_interface *sim)
 {
-       armv4_5_common_t *armv4_5 = target->arch_info;
-       u32 current_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
-       arm_instruction_t instruction;
+       uint32_t current_pc = sim->get_reg(sim, 15);
+       struct arm_instruction instruction;
        int instruction_size;
        int retval = ERROR_OK;
-       
-       if (armv4_5->core_state == ARMV4_5_STATE_ARM)
-       {
-               u32 opcode;
-               
+
+       if (sim->get_state(sim) == ARM_STATE_ARM) {
+               uint32_t opcode;
+
                /* get current instruction, and identify it */
-               if((retval = target_read_u32(target, current_pc, &opcode)) != ERROR_OK)
-               {
+               retval = target_read_u32(target, current_pc, &opcode);
+               if (retval != ERROR_OK)
                        return retval;
-               }
-               if((retval = arm_evaluate_opcode(opcode, current_pc, &instruction)) != ERROR_OK)
-               {
+               retval = arm_evaluate_opcode(opcode, current_pc, &instruction);
+               if (retval != ERROR_OK)
                        return retval;
-               }
                instruction_size = 4;
-               
+
                /* check condition code (for all instructions) */
-               if (!pass_condition(buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32), opcode))
-               {
+               if (!pass_condition(sim->get_cpsr(sim, 0, 32), opcode)) {
                        if (dry_run_pc)
-                       {
                                *dry_run_pc = current_pc + instruction_size;
-                       }
                        else
-                       {
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
-                       }
-                       
+                               sim->set_reg(sim, 15, current_pc + instruction_size);
+
                        return ERROR_OK;
                }
-       }
-       else
-       {
-               u16 opcode;
-               
-               if((retval = target_read_u16(target, current_pc, &opcode)) != ERROR_OK)
-               {
+       } else {
+               uint16_t opcode;
+
+               retval = target_read_u16(target, current_pc, &opcode);
+               if (retval != ERROR_OK)
                        return retval;
-               }
-               if((retval = thumb_evaluate_opcode(opcode, current_pc, &instruction)) != ERROR_OK)
-               {
+               retval = thumb_evaluate_opcode(opcode, current_pc, &instruction);
+               if (retval != ERROR_OK)
                        return retval;
-                       }
                instruction_size = 2;
-               
-               /* check condition code (only for branch instructions) */
-               if ((!thumb_pass_branch_condition(buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32), opcode)) &&
-                       (instruction.type == ARM_B))
-               {
+
+               /* 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
-                       {
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
-                       }
-                       
+                               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))
-       {
-               u32 target;
-               
+       if ((instruction.type >= ARM_B) && (instruction.type <= ARM_BLX)) {
+               uint32_t target_address;
+
                if (instruction.info.b_bl_bx_blx.reg_operand == -1)
-               {
-                       target = instruction.info.b_bl_bx_blx.target_address;
+                       target_address = instruction.info.b_bl_bx_blx.target_address;
+               else {
+                       target_address = sim->get_reg_mode(sim,
+                                       instruction.info.b_bl_bx_blx.reg_operand);
+                       if (instruction.info.b_bl_bx_blx.reg_operand == 15)
+                               target_address += 2 * instruction_size;
                }
-               else
-               {
-                       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); 
-                       if(instruction.info.b_bl_bx_blx.reg_operand == 15)
-                       {
-                               target += 2 * instruction_size;
-                       }
-               }
-               
-               if (dry_run_pc)
-               {       
-                       *dry_run_pc = target;
+
+               if (dry_run_pc) {
+                       *dry_run_pc = target_address & ~1;
                        return ERROR_OK;
-               }
-               else
-               {
+               } else {
                        if (instruction.type == ARM_B)
-                       {
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target);
-                       }
-                       else if (instruction.type == ARM_BL)
-                       {
-                               u32 old_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
-                               buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 14).value, 0, 32, old_pc + 4);
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target);
-                       }
-                       else if (instruction.type == ARM_BX)
-                       {
-                               if (target & 0x1)
-                               {
-                                       armv4_5->core_state = ARMV4_5_STATE_THUMB;
-                               }
+                               sim->set_reg(sim, 15, target_address);
+                       else if (instruction.type == ARM_BL) {
+                               uint32_t old_pc = sim->get_reg(sim, 15);
+                               int T = (sim->get_state(sim) == ARM_STATE_THUMB);
+                               sim->set_reg_mode(sim, 14, old_pc + 4 + T);
+                               sim->set_reg(sim, 15, target_address);
+                       } else if (instruction.type == ARM_BX) {
+                               if (target_address & 0x1)
+                                       sim->set_state(sim, ARM_STATE_THUMB);
                                else
-                               {
-                                       armv4_5->core_state = ARMV4_5_STATE_ARM;
-                               }
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target & 0xfffffffe);
-                       }
-                       else if (instruction.type == ARM_BLX)
-                       {
-                               u32 old_pc = buf_get_u32(armv4_5->core_cache->reg_list[15].value, 0, 32);
-                               buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 14).value, 0, 32, old_pc + 4);
-
-                               if (target & 0x1)
-                               {
-                                       armv4_5->core_state = ARMV4_5_STATE_THUMB;
-                               }
+                                       sim->set_state(sim, ARM_STATE_ARM);
+                               sim->set_reg(sim, 15, target_address & 0xfffffffe);
+                       } else if (instruction.type == ARM_BLX) {
+                               uint32_t old_pc = sim->get_reg(sim, 15);
+                               int T = (sim->get_state(sim) == ARM_STATE_THUMB);
+                               sim->set_reg_mode(sim, 14, old_pc + 4 + T);
+
+                               if (target_address & 0x1)
+                                       sim->set_state(sim, ARM_STATE_THUMB);
                                else
-                               {
-                                       armv4_5->core_state = ARMV4_5_STATE_ARM;
-                               }
-                               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, target & 0xfffffffe);
+                                       sim->set_state(sim, ARM_STATE_ARM);
+                               sim->set_reg(sim, 15, target_address & 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)))
-       {
-               u32 Rd, Rn, shifter_operand;
-               u8 C = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
-               u8 carry_out;
-               
+               || ((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 = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, instruction.info.data_proc.Rn).value, 0, 32);
+                       Rn = sim->get_reg_mode(sim, instruction.info.data_proc.Rn);
                else
                        Rn = 0;
 
-               shifter_operand = arm_shifter_operand(armv4_5, instruction.info.data_proc.variant, instruction.info.data_proc.shifter_operand, &carry_out);
+               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)
@@ -453,293 +399,326 @@ int arm_simulate_step(target_t *target, u32 *dry_run_pc)
                        Rd = ~shifter_operand;
                else
                        LOG_WARNING("unhandled instruction type");
-               
-               if (dry_run_pc)
-               {
+
+               if (dry_run_pc) {
                        if (instruction.info.data_proc.Rd == 15)
-                       {
-                               *dry_run_pc = Rd;
-                               return ERROR_OK;
-                       }
+                               *dry_run_pc = Rd & ~1;
                        else
-                       {
                                *dry_run_pc = current_pc + instruction_size;
-                       }
-                       
-                       return ERROR_OK;
-               }
-               else
-               {
-                       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);
-                       LOG_WARNING("no updating of flags yet");
 
-                       if (instruction.info.data_proc.Rd == 15)  
+                       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, ARM_STATE_THUMB);
+                               else
+                                       sim->set_state(sim, ARM_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)
-               {
+       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
-               {
+               } else
                        LOG_WARNING("no updating of flags yet");
-               }
        }
        /* load register instructions */
-       else if ((instruction.type >= ARM_LDR) && (instruction.type <= ARM_LDRSH))
-       {
-               u32 load_address = 0, modified_address = 0, load_value;
-               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);
-               
+       else if ((instruction.type >= ARM_LDR) && (instruction.type <= ARM_LDRSH)) {
+               uint32_t load_address = 0, modified_address = 0, load_value = 0;
+               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.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)
-               {
-                       u32 offset;
-                       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);
-                       u8 shift = instruction.info.load_store.offset.reg.shift;
-                       u8 shift_imm = instruction.info.load_store.offset.reg.shift_imm;
-                       u8 carry = buf_get_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 29, 1);
-                       
+               } 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
-               {
+               } else
                        LOG_ERROR("BUG: offset_mode neither 0 (offset) nor 1 (scaled register)");
-               }
-               
-               if (instruction.info.load_store.index_mode == 0)
-               {
+
+               if (instruction.info.load_store.index_mode == 0) {
                        /* offset mode
-                        * we load from the modified address, but don't change the base address register */
+                        * 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)
-               {
+               } 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 */
+                        * 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)
-               {
+               } 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;
+                        * 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))
-               {
-                       if((retval = target_read_u32(target, load_address, &load_value)) != ERROR_OK)
-                       {
+
+               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 (dry_run_pc) {
                        if (instruction.info.load_store.Rd == 15)
-                       {
-                               *dry_run_pc = load_value;
-                               return ERROR_OK;
-                       }
+                               *dry_run_pc = load_value & ~1;
                        else
-                       {
                                *dry_run_pc = current_pc + instruction_size;
-                       }
-                       
                        return ERROR_OK;
-               }
-               else
-               {
+               } else {
                        if ((instruction.info.load_store.index_mode == 1) ||
                                (instruction.info.load_store.index_mode == 2))
-                       {
-                               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);
-                       } 
-                       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);
-                       
-                       if (instruction.info.load_store.Rd == 15)
+                               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, ARM_STATE_THUMB);
+                               else
+                                       sim->set_state(sim, ARM_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)
-       {
+       else if (instruction.type == ARM_LDM) {
                int i;
-               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);
-               u32 load_values[16];
+               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++)
-               {
+               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;
+
+               switch (instruction.info.load_store_multiple.addressing_mode) {
+                       case 0: /* Increment after */
+                               /* Rn = Rn; */
                                break;
-                       case 1: /* Increment before */
+                       case 1: /* Increment before */
                                Rn = Rn + 4;
                                break;
-                       case 2: /* Decrement after */
-                               Rn = Rn - (bits_set * 4) + 4; 
+                       case 2: /* Decrement after */
+                               Rn = Rn - (bits_set * 4) + 4;
                                break;
-                       case 3: /* Decrement before */
+                       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))
-                               {
+               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];
+
+               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 = armv4_5->core_mode;
+               } else {
                        int update_cpsr = 0;
 
-                       if (instruction.info.load_store_multiple.S)
-                       {
+                       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))
-                               {
-                                       buf_set_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, mode, i).value, 0, 32, load_values[i]);
+                       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, ARM_STATE_THUMB);
+                                               else
+                                                       sim->set_state(sim, ARM_STATE_ARM);
+                                       } else
+                                               sim->set_reg_mode(sim, i, load_values[i]);
                                }
                        }
-                       
-                       if (update_cpsr)
-                       {
-                               u32 spsr = buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, 16).value, 0, 32);
-                               buf_set_u32(armv4_5->core_cache->reg_list[ARMV4_5_CPSR].value, 0, 32, spsr);
+
+                       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)
-                               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); 
-                       
+                               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)
-       {
+       else if (instruction.type == ARM_STM) {
                int i;
 
-               if (dry_run_pc)
-               {
+               if (dry_run_pc) {
                        /* STM wont affect PC (advance by instruction size */
-               }
-               else
-               {
-                       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);
+               } else {
+                       uint32_t Rn = sim->get_reg_mode(sim,
+                                       instruction.info.load_store_multiple.Rn);
                        int bits_set = 0;
-                       enum armv4_5_mode mode = armv4_5->core_mode;
 
-                       for (i = 0; i < 16; i++)
-                       {
+                       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;
+
+                       switch (instruction.info.load_store_multiple.addressing_mode) {
+                               case 0: /* Increment after */
+                                       /* Rn = Rn; */
                                        break;
-                               case 1: /* Increment before */
+                               case 1: /* Increment before */
                                        Rn = Rn + 4;
                                        break;
-                               case 2: /* Decrement after */
-                                       Rn = Rn - (bits_set * 4) + 4; 
+                               case 2: /* Decrement after */
+                                       Rn = Rn - (bits_set * 4) + 4;
                                        break;
-                               case 3: /* Decrement before */
+                               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, buf_get_u32(ARMV4_5_CORE_REG_MODE(armv4_5->core_cache, armv4_5->core_mode, i).value, 0, 32));
+
+                       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)
-                               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); 
-                       
+                               sim->set_reg_mode(sim,
+                                       instruction.info.load_store_multiple.Rn, Rn);
+
                }
-       }
-       else if (!dry_run_pc)
-       {
+       } else if (!dry_run_pc) {
                /* the instruction wasn't handled, but we're supposed to simulate it
                 */
-               return ERROR_ARM_SIMULATOR_NOT_IMPLEMENTED;
+               LOG_ERROR("Unimplemented instruction, could not simulate it.");
+               return ERROR_FAIL;
        }
-       
-       if (dry_run_pc)
-       {
+
+       if (dry_run_pc) {
                *dry_run_pc = current_pc + instruction_size;
                return ERROR_OK;
-       }
-       else
-       {
-               buf_set_u32(armv4_5->core_cache->reg_list[15].value, 0, 32, current_pc + instruction_size);
+       } 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 *arm = (struct arm *)sim->user_data;
+
+       return buf_get_u32(arm->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 *arm = (struct arm *)sim->user_data;
+
+       buf_set_u32(arm->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 *arm = (struct arm *)sim->user_data;
+
+       return buf_get_u32(ARMV4_5_CORE_REG_MODE(arm->core_cache,
+                       arm->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 *arm = (struct arm *)sim->user_data;
+
+       buf_set_u32(ARMV4_5_CORE_REG_MODE(arm->core_cache,
+               arm->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 *arm = (struct arm *)sim->user_data;
+
+       return buf_get_u32(arm->cpsr->value, pos, bits);
+}
+
+static enum arm_state armv4_5_get_state(struct arm_sim_interface *sim)
+{
+       struct arm *arm = (struct arm *)sim->user_data;
+
+       return arm->core_state;
+}
+
+static void armv4_5_set_state(struct arm_sim_interface *sim, enum arm_state mode)
+{
+       struct arm *arm = (struct arm *)sim->user_data;
+
+       arm->core_state = mode;
+}
+
+static enum arm_mode armv4_5_get_mode(struct arm_sim_interface *sim)
+{
+       struct arm *arm = (struct arm *)sim->user_data;
+
+       return arm->core_mode;
+}
+
+int arm_simulate_step(struct target *target, uint32_t *dry_run_pc)
+{
+       struct arm *arm = target_to_arm(target);
+       struct arm_sim_interface sim;
+
+       sim.user_data = arm;
+       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);
 }