text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013, 2014 Damien P. George
   *
   * Permission is hereby granted, free of charge, to any person obtaining a copy
   * of this software and associated documentation files (the "Software"), to deal
   * in the Software without restriction, including without limitation the rights
   * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   * copies of the Software, and to permit persons to whom the Software is
   * furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
   * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
   * THE SOFTWARE.
   */
  
  #include <stdint.h>
  #include <stdio.h>
  #include <string.h>
  #include <stdarg.h>
  #include <assert.h>
  
  #include "py/emit.h"
  #include "py/asmthumb.h"
  
  #if MICROPY_EMIT_INLINE_THUMB
  
  typedef enum {
  // define rules with a compile function
  #define DEF_RULE(rule, comp, kind, ...) PN_##rule,
  #define DEF_RULE_NC(rule, kind, ...)
      #include "py/grammar.h"
  #undef DEF_RULE
  #undef DEF_RULE_NC
      PN_const_object, // special node for a constant, generic Python object
  // define rules without a compile function
  #define DEF_RULE(rule, comp, kind, ...)
  #define DEF_RULE_NC(rule, kind, ...) PN_##rule,
      #include "py/grammar.h"
  #undef DEF_RULE
  #undef DEF_RULE_NC
  } pn_kind_t;
  
  struct _emit_inline_asm_t {
      asm_thumb_t as;
      uint16_t pass;
      mp_obj_t *error_slot;
      mp_uint_t max_num_labels;
      qstr *label_lookup;
  };
  
  STATIC void emit_inline_thumb_error_msg(emit_inline_asm_t *emit, const char *msg) {
      *emit->error_slot = mp_obj_new_exception_msg(&mp_type_SyntaxError, msg);
  }
  
  STATIC void emit_inline_thumb_error_exc(emit_inline_asm_t *emit, mp_obj_t exc) {
      *emit->error_slot = exc;
  }
  
  emit_inline_asm_t *emit_inline_thumb_new(mp_uint_t max_num_labels) {
      emit_inline_asm_t *emit = m_new_obj(emit_inline_asm_t);
      memset(&emit->as, 0, sizeof(emit->as));
      mp_asm_base_init(&emit->as.base, max_num_labels);
      emit->max_num_labels = max_num_labels;
      emit->label_lookup = m_new(qstr, max_num_labels);
      return emit;
  }
  
  void emit_inline_thumb_free(emit_inline_asm_t *emit) {
      m_del(qstr, emit->label_lookup, emit->max_num_labels);
      mp_asm_base_deinit(&emit->as.base, false);
      m_del_obj(emit_inline_asm_t, emit);
  }
  
  STATIC void emit_inline_thumb_start_pass(emit_inline_asm_t *emit, pass_kind_t pass, mp_obj_t *error_slot) {
      emit->pass = pass;
      emit->error_slot = error_slot;
      if (emit->pass == MP_PASS_CODE_SIZE) {
          memset(emit->label_lookup, 0, emit->max_num_labels * sizeof(qstr));
      }
      mp_asm_base_start_pass(&emit->as.base, pass == MP_PASS_EMIT ? MP_ASM_PASS_EMIT : MP_ASM_PASS_COMPUTE);
      asm_thumb_entry(&emit->as, 0);
  }
  
  STATIC void emit_inline_thumb_end_pass(emit_inline_asm_t *emit, mp_uint_t type_sig) {
      asm_thumb_exit(&emit->as);
      asm_thumb_end_pass(&emit->as);
  }
  
  STATIC mp_uint_t emit_inline_thumb_count_params(emit_inline_asm_t *emit, mp_uint_t n_params, mp_parse_node_t *pn_params) {
      if (n_params > 4) {
          emit_inline_thumb_error_msg(emit, "can only have up to 4 parameters to Thumb assembly");
          return 0;
      }
      for (mp_uint_t i = 0; i < n_params; i++) {
          if (!MP_PARSE_NODE_IS_ID(pn_params[i])) {
              emit_inline_thumb_error_msg(emit, "parameters must be registers in sequence r0 to r3");
              return 0;
          }
          const char *p = qstr_str(MP_PARSE_NODE_LEAF_ARG(pn_params[i]));
          if (!(strlen(p) == 2 && p[0] == 'r' && p[1] == '0' + i)) {
              emit_inline_thumb_error_msg(emit, "parameters must be registers in sequence r0 to r3");
              return 0;
          }
      }
      return n_params;
  }
  
  STATIC bool emit_inline_thumb_label(emit_inline_asm_t *emit, mp_uint_t label_num, qstr label_id) {
      assert(label_num < emit->max_num_labels);
      if (emit->pass == MP_PASS_CODE_SIZE) {
          // check for duplicate label on first pass
          for (uint i = 0; i < emit->max_num_labels; i++) {
              if (emit->label_lookup[i] == label_id) {
                  return false;
              }
          }
      }
      emit->label_lookup[label_num] = label_id;
      mp_asm_base_label_assign(&emit->as.base, label_num);
      return true;
  }
  
  typedef struct _reg_name_t { byte reg;
                               byte name[3];
  } reg_name_t;
  STATIC const reg_name_t reg_name_table[] = {
      {0, "r0\0"},
      {1, "r1\0"},
      {2, "r2\0"},
      {3, "r3\0"},
      {4, "r4\0"},
      {5, "r5\0"},
      {6, "r6\0"},
      {7, "r7\0"},
      {8, "r8\0"},
      {9, "r9\0"},
      {10, "r10"},
      {11, "r11"},
      {12, "r12"},
      {13, "r13"},
      {14, "r14"},
      {15, "r15"},
      {10, "sl\0"},
      {11, "fp\0"},
      {13, "sp\0"},
      {14, "lr\0"},
      {15, "pc\0"},
  };
  
  #define MAX_SPECIAL_REGISTER_NAME_LENGTH 7
  typedef struct _special_reg_name_t { byte reg;
                                       char name[MAX_SPECIAL_REGISTER_NAME_LENGTH + 1];
  } special_reg_name_t;
  STATIC const special_reg_name_t special_reg_name_table[] = {
      {5, "IPSR"},
      {17, "BASEPRI"},
  };
  
  // return empty string in case of error, so we can attempt to parse the string
  // without a special check if it was in fact a string
  STATIC const char *get_arg_str(mp_parse_node_t pn) {
      if (MP_PARSE_NODE_IS_ID(pn)) {
          qstr qst = MP_PARSE_NODE_LEAF_ARG(pn);
          return qstr_str(qst);
      } else {
          return "";
      }
  }
  
  STATIC mp_uint_t get_arg_reg(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn, mp_uint_t max_reg) {
      const char *reg_str = get_arg_str(pn);
      for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(reg_name_table); i++) {
          const reg_name_t *r = &reg_name_table[i];
          if (reg_str[0] == r->name[0]
              && reg_str[1] == r->name[1]
              && reg_str[2] == r->name[2]
              && (reg_str[2] == '\0' || reg_str[3] == '\0')) {
              if (r->reg > max_reg) {
                  emit_inline_thumb_error_exc(emit,
                      mp_obj_new_exception_msg_varg(&mp_type_SyntaxError,
                          "'%s' expects at most r%d", op, max_reg));
                  return 0;
              } else {
                  return r->reg;
              }
          }
      }
      emit_inline_thumb_error_exc(emit,
          mp_obj_new_exception_msg_varg(&mp_type_SyntaxError,
              "'%s' expects a register", op));
      return 0;
  }
  
  STATIC mp_uint_t get_arg_special_reg(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn) {
      const char *reg_str = get_arg_str(pn);
      for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(special_reg_name_table); i++) {
          const special_reg_name_t *r = &special_reg_name_table[i];
          if (strcmp(r->name, reg_str) == 0) {
              return r->reg;
          }
      }
      emit_inline_thumb_error_exc(emit,
          mp_obj_new_exception_msg_varg(&mp_type_SyntaxError,
              "'%s' expects a special register", op));
      return 0;
  }
  
  #if MICROPY_EMIT_INLINE_THUMB_FLOAT
  STATIC mp_uint_t get_arg_vfpreg(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn) {
      const char *reg_str = get_arg_str(pn);
      if (reg_str[0] == 's' && reg_str[1] != '\0') {
          mp_uint_t regno = 0;
          for (++reg_str; *reg_str; ++reg_str) {
              mp_uint_t v = *reg_str;
              if (!('0' <= v && v <= '9')) {
                  goto malformed;
              }
              regno = 10 * regno + v - '0';
          }
          if (regno > 31) {
              emit_inline_thumb_error_exc(emit,
                  mp_obj_new_exception_msg_varg(&mp_type_SyntaxError,
                      "'%s' expects at most r%d", op, 31));
              return 0;
          } else {
              return regno;
          }
      }
  malformed:
      emit_inline_thumb_error_exc(emit,
          mp_obj_new_exception_msg_varg(&mp_type_SyntaxError,
              "'%s' expects an FPU register", op));
      return 0;
  }
  #endif
  
  STATIC mp_uint_t get_arg_reglist(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn) {
      // a register list looks like {r0, r1, r2} and is parsed as a Python set
  
      if (!MP_PARSE_NODE_IS_STRUCT_KIND(pn, PN_atom_brace)) {
          goto bad_arg;
      }
  
      mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
      assert(MP_PARSE_NODE_STRUCT_NUM_NODES(pns) == 1); // should always be
      pn = pns->nodes[0];
  
      mp_uint_t reglist = 0;
  
      if (MP_PARSE_NODE_IS_ID(pn)) {
          // set with one element
          reglist |= 1 << get_arg_reg(emit, op, pn, 15);
      } else if (MP_PARSE_NODE_IS_STRUCT(pn)) {
          pns = (mp_parse_node_struct_t *)pn;
          if (MP_PARSE_NODE_STRUCT_KIND(pns) == PN_dictorsetmaker) {
              assert(MP_PARSE_NODE_IS_STRUCT(pns->nodes[1])); // should succeed
              mp_parse_node_struct_t *pns1 = (mp_parse_node_struct_t *)pns->nodes[1];
              if (MP_PARSE_NODE_STRUCT_KIND(pns1) == PN_dictorsetmaker_list) {
                  // set with multiple elements
  
                  // get first element of set (we rely on get_arg_reg to catch syntax errors)
                  reglist |= 1 << get_arg_reg(emit, op, pns->nodes[0], 15);
  
                  // get tail elements (2nd, 3rd, ...)
                  mp_parse_node_t *nodes;
                  int n = mp_parse_node_extract_list(&pns1->nodes[0], PN_dictorsetmaker_list2, &nodes);
  
                  // process rest of elements
                  for (int i = 0; i < n; i++) {
                      reglist |= 1 << get_arg_reg(emit, op, nodes[i], 15);
                  }
              } else {
                  goto bad_arg;
              }
          } else {
              goto bad_arg;
          }
      } else {
          goto bad_arg;
      }
  
      return reglist;
  
  bad_arg:
      emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "'%s' expects {r0, r1, ...}", op));
      return 0;
  }
  
  STATIC uint32_t get_arg_i(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn, uint32_t fit_mask) {
      mp_obj_t o;
      if (!mp_parse_node_get_int_maybe(pn, &o)) {
          emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "'%s' expects an integer", op));
          return 0;
      }
      uint32_t i = mp_obj_get_int_truncated(o);
      if ((i & (~fit_mask)) != 0) {
          emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "'%s' integer 0x%x doesn't fit in mask 0x%x", op, i, fit_mask));
          return 0;
      }
      return i;
  }
  
  STATIC bool get_arg_addr(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn, mp_parse_node_t *pn_base, mp_parse_node_t *pn_offset) {
      if (!MP_PARSE_NODE_IS_STRUCT_KIND(pn, PN_atom_bracket)) {
          goto bad_arg;
      }
      mp_parse_node_struct_t *pns = (mp_parse_node_struct_t *)pn;
      if (!MP_PARSE_NODE_IS_STRUCT_KIND(pns->nodes[0], PN_testlist_comp)) {
          goto bad_arg;
      }
      pns = (mp_parse_node_struct_t *)pns->nodes[0];
      if (MP_PARSE_NODE_STRUCT_NUM_NODES(pns) != 2) {
          goto bad_arg;
      }
  
      *pn_base = pns->nodes[0];
      *pn_offset = pns->nodes[1];
      return true;
  
  bad_arg:
      emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "'%s' expects an address of the form [a, b]", op));
      return false;
  }
  
  STATIC int get_arg_label(emit_inline_asm_t *emit, const char *op, mp_parse_node_t pn) {
      if (!MP_PARSE_NODE_IS_ID(pn)) {
          emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "'%s' expects a label", op));
          return 0;
      }
      qstr label_qstr = MP_PARSE_NODE_LEAF_ARG(pn);
      for (uint i = 0; i < emit->max_num_labels; i++) {
          if (emit->label_lookup[i] == label_qstr) {
              return i;
          }
      }
      // only need to have the labels on the last pass
      if (emit->pass == MP_PASS_EMIT) {
          emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "label '%q' not defined", label_qstr));
      }
      return 0;
  }
  
  typedef struct _cc_name_t { byte cc;
                              byte name[2];
  } cc_name_t;
  STATIC const cc_name_t cc_name_table[] = {
      { ASM_THUMB_CC_EQ, "eq" },
      { ASM_THUMB_CC_NE, "ne" },
      { ASM_THUMB_CC_CS, "cs" },
      { ASM_THUMB_CC_CC, "cc" },
      { ASM_THUMB_CC_MI, "mi" },
      { ASM_THUMB_CC_PL, "pl" },
      { ASM_THUMB_CC_VS, "vs" },
      { ASM_THUMB_CC_VC, "vc" },
      { ASM_THUMB_CC_HI, "hi" },
      { ASM_THUMB_CC_LS, "ls" },
      { ASM_THUMB_CC_GE, "ge" },
      { ASM_THUMB_CC_LT, "lt" },
      { ASM_THUMB_CC_GT, "gt" },
      { ASM_THUMB_CC_LE, "le" },
  };
  
  typedef struct _format_4_op_t { byte op;
                                  char name[3];
  } format_4_op_t;
  #define X(x) (((x) >> 4) & 0xff) // only need 1 byte to distinguish these ops
  STATIC const format_4_op_t format_4_op_table[] = {
      { X(ASM_THUMB_FORMAT_4_EOR), "eor" },
      { X(ASM_THUMB_FORMAT_4_LSL), "lsl" },
      { X(ASM_THUMB_FORMAT_4_LSR), "lsr" },
      { X(ASM_THUMB_FORMAT_4_ASR), "asr" },
      { X(ASM_THUMB_FORMAT_4_ADC), "adc" },
      { X(ASM_THUMB_FORMAT_4_SBC), "sbc" },
      { X(ASM_THUMB_FORMAT_4_ROR), "ror" },
      { X(ASM_THUMB_FORMAT_4_TST), "tst" },
      { X(ASM_THUMB_FORMAT_4_NEG), "neg" },
      { X(ASM_THUMB_FORMAT_4_CMP), "cmp" },
      { X(ASM_THUMB_FORMAT_4_CMN), "cmn" },
      { X(ASM_THUMB_FORMAT_4_ORR), "orr" },
      { X(ASM_THUMB_FORMAT_4_MUL), "mul" },
      { X(ASM_THUMB_FORMAT_4_BIC), "bic" },
      { X(ASM_THUMB_FORMAT_4_MVN), "mvn" },
  };
  #undef X
  
  // name is actually a qstr, which should fit in 16 bits
  typedef struct _format_9_10_op_t { uint16_t op;
                                     uint16_t name;
  } format_9_10_op_t;
  #define X(x) (x)
  STATIC const format_9_10_op_t format_9_10_op_table[] = {
      { X(ASM_THUMB_FORMAT_9_LDR | ASM_THUMB_FORMAT_9_WORD_TRANSFER), MP_QSTR_ldr },
      { X(ASM_THUMB_FORMAT_9_LDR | ASM_THUMB_FORMAT_9_BYTE_TRANSFER), MP_QSTR_ldrb },
      { X(ASM_THUMB_FORMAT_10_LDRH), MP_QSTR_ldrh },
      { X(ASM_THUMB_FORMAT_9_STR | ASM_THUMB_FORMAT_9_WORD_TRANSFER), MP_QSTR_str },
      { X(ASM_THUMB_FORMAT_9_STR | ASM_THUMB_FORMAT_9_BYTE_TRANSFER), MP_QSTR_strb },
      { X(ASM_THUMB_FORMAT_10_STRH), MP_QSTR_strh },
  };
  #undef X
  
  #if MICROPY_EMIT_INLINE_THUMB_FLOAT
  // actual opcodes are: 0xee00 | op.hi_nibble, 0x0a00 | op.lo_nibble
  typedef struct _format_vfp_op_t { byte op;
                                    char name[3];
  } format_vfp_op_t;
  STATIC const format_vfp_op_t format_vfp_op_table[] = {
      { 0x30, "add" },
      { 0x34, "sub" },
      { 0x20, "mul" },
      { 0x80, "div" },
  };
  #endif
  
  // shorthand alias for whether we allow ARMv7-M instructions
  #define ARMV7M MICROPY_EMIT_INLINE_THUMB_ARMV7M
  
  STATIC void emit_inline_thumb_op(emit_inline_asm_t *emit, qstr op, mp_uint_t n_args, mp_parse_node_t *pn_args) {
      // TODO perhaps make two tables:
      // one_args =
      // "b", LAB, asm_thumb_b_n,
      // "bgt", LAB, asm_thumb_bgt_n,
      // two_args =
      // "movs", RLO, I8, asm_thumb_movs_reg_i8
      // "movw", REG, REG, asm_thumb_movw_reg_i16
      // three_args =
      // "subs", RLO, RLO, I3, asm_thumb_subs_reg_reg_i3
  
      size_t op_len;
      const char *op_str = (const char *)qstr_data(op, &op_len);
  
      #if MICROPY_EMIT_INLINE_THUMB_FLOAT
      if (op_str[0] == 'v') {
          // floating point operations
          if (n_args == 2) {
              mp_uint_t op_code = 0x0ac0, op_code_hi;
              if (op == MP_QSTR_vcmp) {
                  op_code_hi = 0xeeb4;
              op_vfp_twoargs:;
                  mp_uint_t vd = get_arg_vfpreg(emit, op_str, pn_args[0]);
                  mp_uint_t vm = get_arg_vfpreg(emit, op_str, pn_args[1]);
                  asm_thumb_op32(&emit->as,
                      op_code_hi | ((vd & 1) << 6),
                      op_code | ((vd & 0x1e) << 11) | ((vm & 1) << 5) | (vm & 0x1e) >> 1);
              } else if (op == MP_QSTR_vsqrt) {
                  op_code_hi = 0xeeb1;
                  goto op_vfp_twoargs;
              } else if (op == MP_QSTR_vneg) {
                  op_code_hi = 0xeeb1;
                  op_code = 0x0a40;
                  goto op_vfp_twoargs;
              } else if (op == MP_QSTR_vcvt_f32_s32) {
                  op_code_hi = 0xeeb8; // int to float
                  goto op_vfp_twoargs;
              } else if (op == MP_QSTR_vcvt_s32_f32) {
                  op_code_hi = 0xeebd; // float to int
                  goto op_vfp_twoargs;
              } else if (op == MP_QSTR_vmrs) {
                  mp_uint_t reg_dest;
                  const char *reg_str0 = get_arg_str(pn_args[0]);
                  if (strcmp(reg_str0, "APSR_nzcv") == 0) {
                      reg_dest = 15;
                  } else {
                      reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                  }
                  const char *reg_str1 = get_arg_str(pn_args[1]);
                  if (strcmp(reg_str1, "FPSCR") == 0) {
                      // FP status to ARM reg
                      asm_thumb_op32(&emit->as, 0xeef1, 0x0a10 | (reg_dest << 12));
                  } else {
                      goto unknown_op;
                  }
              } else if (op == MP_QSTR_vmov) {
                  op_code_hi = 0xee00;
                  mp_uint_t r_arm, vm;
                  const char *reg_str = get_arg_str(pn_args[0]);
                  if (reg_str[0] == 'r') {
                      r_arm = get_arg_reg(emit, op_str, pn_args[0], 15);
                      vm = get_arg_vfpreg(emit, op_str, pn_args[1]);
                      op_code_hi |= 0x10;
                  } else {
                      vm = get_arg_vfpreg(emit, op_str, pn_args[0]);
                      r_arm = get_arg_reg(emit, op_str, pn_args[1], 15);
                  }
                  asm_thumb_op32(&emit->as,
                      op_code_hi | ((vm & 0x1e) >> 1),
                      0x0a10 | (r_arm << 12) | ((vm & 1) << 7));
              } else if (op == MP_QSTR_vldr) {
                  op_code_hi = 0xed90;
              op_vldr_vstr:;
                  mp_uint_t vd = get_arg_vfpreg(emit, op_str, pn_args[0]);
                  mp_parse_node_t pn_base, pn_offset;
                  if (get_arg_addr(emit, op_str, pn_args[1], &pn_base, &pn_offset)) {
                      mp_uint_t rlo_base = get_arg_reg(emit, op_str, pn_base, 7);
                      mp_uint_t i8;
                      i8 = get_arg_i(emit, op_str, pn_offset, 0x3fc) >> 2;
                      asm_thumb_op32(&emit->as,
                          op_code_hi | rlo_base | ((vd & 1) << 6),
                          0x0a00 | ((vd & 0x1e) << 11) | i8);
                  }
              } else if (op == MP_QSTR_vstr) {
                  op_code_hi = 0xed80;
                  goto op_vldr_vstr;
              } else {
                  goto unknown_op;
              }
          } else if (n_args == 3) {
              // search table for arith ops
              for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(format_vfp_op_table); i++) {
                  if (strncmp(op_str + 1, format_vfp_op_table[i].name, 3) == 0 && op_str[4] == '\0') {
                      mp_uint_t op_code_hi = 0xee00 | (format_vfp_op_table[i].op & 0xf0);
                      mp_uint_t op_code = 0x0a00 | ((format_vfp_op_table[i].op & 0x0f) << 4);
                      mp_uint_t vd = get_arg_vfpreg(emit, op_str, pn_args[0]);
                      mp_uint_t vn = get_arg_vfpreg(emit, op_str, pn_args[1]);
                      mp_uint_t vm = get_arg_vfpreg(emit, op_str, pn_args[2]);
                      asm_thumb_op32(&emit->as,
                          op_code_hi | ((vd & 1) << 6) | (vn >> 1),
                          op_code | (vm >> 1) | ((vm & 1) << 5) | ((vd & 0x1e) << 11) | ((vn & 1) << 7));
                      return;
                  }
              }
              goto unknown_op;
          } else {
              goto unknown_op;
          }
          return;
      }
      #endif
  
      if (n_args == 0) {
          if (op == MP_QSTR_nop) {
              asm_thumb_op16(&emit->as, ASM_THUMB_OP_NOP);
          } else if (op == MP_QSTR_wfi) {
              asm_thumb_op16(&emit->as, ASM_THUMB_OP_WFI);
          } else {
              goto unknown_op;
          }
  
      } else if (n_args == 1) {
          if (op == MP_QSTR_b) {
              int label_num = get_arg_label(emit, op_str, pn_args[0]);
              if (!asm_thumb_b_n_label(&emit->as, label_num)) {
                  goto branch_not_in_range;
              }
          } else if (op == MP_QSTR_bl) {
              int label_num = get_arg_label(emit, op_str, pn_args[0]);
              if (!asm_thumb_bl_label(&emit->as, label_num)) {
                  goto branch_not_in_range;
              }
          } else if (op == MP_QSTR_bx) {
              mp_uint_t r = get_arg_reg(emit, op_str, pn_args[0], 15);
              asm_thumb_op16(&emit->as, 0x4700 | (r << 3));
          } else if (op_str[0] == 'b' && (op_len == 3
                                          || (op_len == 5 && op_str[3] == '_'
                                              && (op_str[4] == 'n' || (ARMV7M && op_str[4] == 'w'))))) {
              mp_uint_t cc = -1;
              for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(cc_name_table); i++) {
                  if (op_str[1] == cc_name_table[i].name[0] && op_str[2] == cc_name_table[i].name[1]) {
                      cc = cc_name_table[i].cc;
                  }
              }
              if (cc == (mp_uint_t)-1) {
                  goto unknown_op;
              }
              int label_num = get_arg_label(emit, op_str, pn_args[0]);
              if (!asm_thumb_bcc_nw_label(&emit->as, cc, label_num, op_len == 5 && op_str[4] == 'w')) {
                  goto branch_not_in_range;
              }
          } else if (ARMV7M && op_str[0] == 'i' && op_str[1] == 't') {
              const char *arg_str = get_arg_str(pn_args[0]);
              mp_uint_t cc = -1;
              for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(cc_name_table); i++) {
                  if (arg_str[0] == cc_name_table[i].name[0]
                      && arg_str[1] == cc_name_table[i].name[1]
                      && arg_str[2] == '\0') {
                      cc = cc_name_table[i].cc;
                      break;
                  }
              }
              if (cc == (mp_uint_t)-1) {
                  goto unknown_op;
              }
              const char *os = op_str + 2;
              while (*os != '\0') {
                  os++;
              }
              if (os > op_str + 5) {
                  goto unknown_op;
              }
              mp_uint_t it_mask = 8;
              while (--os >= op_str + 2) {
                  it_mask >>= 1;
                  if (*os == 't') {
                      it_mask |= (cc & 1) << 3;
                  } else if (*os == 'e') {
                      it_mask |= ((~cc) & 1) << 3;
                  } else {
                      goto unknown_op;
                  }
              }
              asm_thumb_it_cc(&emit->as, cc, it_mask);
          } else if (op == MP_QSTR_cpsid) {
              // TODO check pn_args[0] == i
              asm_thumb_op16(&emit->as, ASM_THUMB_OP_CPSID_I);
          } else if (op == MP_QSTR_cpsie) {
              // TODO check pn_args[0] == i
              asm_thumb_op16(&emit->as, ASM_THUMB_OP_CPSIE_I);
          } else if (op == MP_QSTR_push) {
              mp_uint_t reglist = get_arg_reglist(emit, op_str, pn_args[0]);
              if ((reglist & 0xff00) == 0) {
                  asm_thumb_op16(&emit->as, 0xb400 | reglist);
              } else {
                  if (!ARMV7M) {
                      goto unknown_op;
                  }
                  asm_thumb_op32(&emit->as, 0xe92d, reglist);
              }
          } else if (op == MP_QSTR_pop) {
              mp_uint_t reglist = get_arg_reglist(emit, op_str, pn_args[0]);
              if ((reglist & 0xff00) == 0) {
                  asm_thumb_op16(&emit->as, 0xbc00 | reglist);
              } else {
                  if (!ARMV7M) {
                      goto unknown_op;
                  }
                  asm_thumb_op32(&emit->as, 0xe8bd, reglist);
              }
          } else {
              goto unknown_op;
          }
  
      } else if (n_args == 2) {
          if (MP_PARSE_NODE_IS_ID(pn_args[1])) {
              // second arg is a register (or should be)
              mp_uint_t op_code, op_code_hi;
              if (op == MP_QSTR_mov) {
                  mp_uint_t reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                  mp_uint_t reg_src = get_arg_reg(emit, op_str, pn_args[1], 15);
                  asm_thumb_mov_reg_reg(&emit->as, reg_dest, reg_src);
              } else if (ARMV7M && op == MP_QSTR_clz) {
                  op_code_hi = 0xfab0;
                  op_code = 0xf080;
                  mp_uint_t rd, rm;
              op_clz_rbit:
                  rd = get_arg_reg(emit, op_str, pn_args[0], 15);
                  rm = get_arg_reg(emit, op_str, pn_args[1], 15);
                  asm_thumb_op32(&emit->as, op_code_hi | rm, op_code | (rd << 8) | rm);
              } else if (ARMV7M && op == MP_QSTR_rbit) {
                  op_code_hi = 0xfa90;
                  op_code = 0xf0a0;
                  goto op_clz_rbit;
              } else if (ARMV7M && op == MP_QSTR_mrs) {
                  mp_uint_t reg_dest = get_arg_reg(emit, op_str, pn_args[0], 12);
                  mp_uint_t reg_src = get_arg_special_reg(emit, op_str, pn_args[1]);
                  asm_thumb_op32(&emit->as, 0xf3ef, 0x8000 | (reg_dest << 8) | reg_src);
              } else {
                  if (op == MP_QSTR_and_) {
                      op_code = ASM_THUMB_FORMAT_4_AND;
                      mp_uint_t reg_dest, reg_src;
                  op_format_4:
                      reg_dest = get_arg_reg(emit, op_str, pn_args[0], 7);
                      reg_src = get_arg_reg(emit, op_str, pn_args[1], 7);
                      asm_thumb_format_4(&emit->as, op_code, reg_dest, reg_src);
                      return;
                  }
                  // search table for ALU ops
                  for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(format_4_op_table); i++) {
                      if (strncmp(op_str, format_4_op_table[i].name, 3) == 0 && op_str[3] == '\0') {
                          op_code = 0x4000 | (format_4_op_table[i].op << 4);
                          goto op_format_4;
                      }
                  }
                  goto unknown_op;
              }
          } else {
              // second arg is not a register
              mp_uint_t op_code;
              if (op == MP_QSTR_mov) {
                  op_code = ASM_THUMB_FORMAT_3_MOV;
                  mp_uint_t rlo_dest, i8_src;
              op_format_3:
                  rlo_dest = get_arg_reg(emit, op_str, pn_args[0], 7);
                  i8_src = get_arg_i(emit, op_str, pn_args[1], 0xff);
                  asm_thumb_format_3(&emit->as, op_code, rlo_dest, i8_src);
              } else if (op == MP_QSTR_cmp) {
                  op_code = ASM_THUMB_FORMAT_3_CMP;
                  goto op_format_3;
              } else if (op == MP_QSTR_add) {
                  op_code = ASM_THUMB_FORMAT_3_ADD;
                  goto op_format_3;
              } else if (op == MP_QSTR_sub) {
                  op_code = ASM_THUMB_FORMAT_3_SUB;
                  goto op_format_3;
              } else if (ARMV7M && op == MP_QSTR_movw) {
                  op_code = ASM_THUMB_OP_MOVW;
                  mp_uint_t reg_dest;
              op_movw_movt:
                  reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                  int i_src = get_arg_i(emit, op_str, pn_args[1], 0xffff);
                  asm_thumb_mov_reg_i16(&emit->as, op_code, reg_dest, i_src);
              } else if (ARMV7M && op == MP_QSTR_movt) {
                  op_code = ASM_THUMB_OP_MOVT;
                  goto op_movw_movt;
              } else if (ARMV7M && op == MP_QSTR_movwt) {
                  // this is a convenience instruction
                  mp_uint_t reg_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                  uint32_t i_src = get_arg_i(emit, op_str, pn_args[1], 0xffffffff);
                  asm_thumb_mov_reg_i16(&emit->as, ASM_THUMB_OP_MOVW, reg_dest, i_src & 0xffff);
                  asm_thumb_mov_reg_i16(&emit->as, ASM_THUMB_OP_MOVT, reg_dest, (i_src >> 16) & 0xffff);
              } else if (ARMV7M && op == MP_QSTR_ldrex) {
                  mp_uint_t r_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
                  mp_parse_node_t pn_base, pn_offset;
                  if (get_arg_addr(emit, op_str, pn_args[1], &pn_base, &pn_offset)) {
                      mp_uint_t r_base = get_arg_reg(emit, op_str, pn_base, 15);
                      mp_uint_t i8 = get_arg_i(emit, op_str, pn_offset, 0xff) >> 2;
                      asm_thumb_op32(&emit->as, 0xe850 | r_base, 0x0f00 | (r_dest << 12) | i8);
                  }
              } else {
                  // search table for ldr/str instructions
                  for (mp_uint_t i = 0; i < MP_ARRAY_SIZE(format_9_10_op_table); i++) {
                      if (op == format_9_10_op_table[i].name) {
                          op_code = format_9_10_op_table[i].op;
                          mp_parse_node_t pn_base, pn_offset;
                          mp_uint_t rlo_dest = get_arg_reg(emit, op_str, pn_args[0], 7);
                          if (get_arg_addr(emit, op_str, pn_args[1], &pn_base, &pn_offset)) {
                              mp_uint_t rlo_base = get_arg_reg(emit, op_str, pn_base, 7);
                              mp_uint_t i5;
                              if (op_code & ASM_THUMB_FORMAT_9_BYTE_TRANSFER) {
                                  i5 = get_arg_i(emit, op_str, pn_offset, 0x1f);
                              } else if (op_code & ASM_THUMB_FORMAT_10_STRH) { // also catches LDRH
                                  i5 = get_arg_i(emit, op_str, pn_offset, 0x3e) >> 1;
                              } else {
                                  i5 = get_arg_i(emit, op_str, pn_offset, 0x7c) >> 2;
                              }
                              asm_thumb_format_9_10(&emit->as, op_code, rlo_dest, rlo_base, i5);
                              return;
                          }
                          break;
                      }
                  }
                  goto unknown_op;
              }
          }
  
      } else if (n_args == 3) {
          mp_uint_t op_code;
          if (op == MP_QSTR_lsl) {
              op_code = ASM_THUMB_FORMAT_1_LSL;
              mp_uint_t rlo_dest, rlo_src, i5;
          op_format_1:
              rlo_dest = get_arg_reg(emit, op_str, pn_args[0], 7);
              rlo_src = get_arg_reg(emit, op_str, pn_args[1], 7);
              i5 = get_arg_i(emit, op_str, pn_args[2], 0x1f);
              asm_thumb_format_1(&emit->as, op_code, rlo_dest, rlo_src, i5);
          } else if (op == MP_QSTR_lsr) {
              op_code = ASM_THUMB_FORMAT_1_LSR;
              goto op_format_1;
          } else if (op == MP_QSTR_asr) {
              op_code = ASM_THUMB_FORMAT_1_ASR;
              goto op_format_1;
          } else if (op == MP_QSTR_add) {
              op_code = ASM_THUMB_FORMAT_2_ADD;
              mp_uint_t rlo_dest, rlo_src;
          op_format_2:
              rlo_dest = get_arg_reg(emit, op_str, pn_args[0], 7);
              rlo_src = get_arg_reg(emit, op_str, pn_args[1], 7);
              int src_b;
              if (MP_PARSE_NODE_IS_ID(pn_args[2])) {
                  op_code |= ASM_THUMB_FORMAT_2_REG_OPERAND;
                  src_b = get_arg_reg(emit, op_str, pn_args[2], 7);
              } else {
                  op_code |= ASM_THUMB_FORMAT_2_IMM_OPERAND;
                  src_b = get_arg_i(emit, op_str, pn_args[2], 0x7);
              }
              asm_thumb_format_2(&emit->as, op_code, rlo_dest, rlo_src, src_b);
          } else if (ARMV7M && op == MP_QSTR_sdiv) {
              op_code = 0xfb90; // sdiv high part
              mp_uint_t rd, rn, rm;
          op_sdiv_udiv:
              rd = get_arg_reg(emit, op_str, pn_args[0], 15);
              rn = get_arg_reg(emit, op_str, pn_args[1], 15);
              rm = get_arg_reg(emit, op_str, pn_args[2], 15);
              asm_thumb_op32(&emit->as, op_code | rn, 0xf0f0 | (rd << 8) | rm);
          } else if (ARMV7M && op == MP_QSTR_udiv) {
              op_code = 0xfbb0; // udiv high part
              goto op_sdiv_udiv;
          } else if (op == MP_QSTR_sub) {
              op_code = ASM_THUMB_FORMAT_2_SUB;
              goto op_format_2;
          } else if (ARMV7M && op == MP_QSTR_strex) {
              mp_uint_t r_dest = get_arg_reg(emit, op_str, pn_args[0], 15);
              mp_uint_t r_src = get_arg_reg(emit, op_str, pn_args[1], 15);
              mp_parse_node_t pn_base, pn_offset;
              if (get_arg_addr(emit, op_str, pn_args[2], &pn_base, &pn_offset)) {
                  mp_uint_t r_base = get_arg_reg(emit, op_str, pn_base, 15);
                  mp_uint_t i8 = get_arg_i(emit, op_str, pn_offset, 0xff) >> 2;
                  asm_thumb_op32(&emit->as, 0xe840 | r_base, (r_src << 12) | (r_dest << 8) | i8);
              }
          } else {
              goto unknown_op;
          }
  
      } else {
          goto unknown_op;
      }
  
      return;
  
  unknown_op:
      emit_inline_thumb_error_exc(emit, mp_obj_new_exception_msg_varg(&mp_type_SyntaxError, "unsupported Thumb instruction '%s' with %d arguments", op_str, n_args));
      return;
  
  branch_not_in_range:
      emit_inline_thumb_error_msg(emit, "branch not in range");
      return;
  }
  
  const emit_inline_asm_method_table_t emit_inline_thumb_method_table = {
      #if MICROPY_DYNAMIC_COMPILER
      emit_inline_thumb_new,
      emit_inline_thumb_free,
      #endif
  
      emit_inline_thumb_start_pass,
      emit_inline_thumb_end_pass,
      emit_inline_thumb_count_params,
      emit_inline_thumb_label,
      emit_inline_thumb_op,
  };
  
  #endif // MICROPY_EMIT_INLINE_THUMB
  