text: /*
   * This file is part of the Micro Python project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2014 Damien P. George
   * Copyright (c) 2014 Paul Sokolovsky
   *
   * 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 <stdbool.h>
  #include <string.h>
  #include <assert.h>
  
  #include "py/nlr.h"
  #include "py/objfun.h"
  #include "py/runtime0.h"
  #include "py/bc0.h"
  #include "py/bc.h"
  
  #if 0 // print debugging info
  #define DEBUG_PRINT (1)
  #else // don't print debugging info
  #define DEBUG_PRINT (0)
  #define DEBUG_printf(...) (void)0
  #endif
  
  mp_uint_t mp_decode_uint(const byte **ptr) {
      mp_uint_t unum = 0;
      byte val;
      const byte *p = *ptr;
      do {
          val = *p++;
          unum = (unum << 7) | (val & 0x7f);
      } while ((val & 0x80) != 0);
      *ptr = p;
      return unum;
  }
  
  STATIC NORETURN void fun_pos_args_mismatch(mp_obj_fun_bc_t *f, size_t expected, size_t given) {
  #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
      // generic message, used also for other argument issues
      (void)f;
      (void)expected;
      (void)given;
      mp_arg_error_terse_mismatch();
  #elif MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_NORMAL
      (void)f;
      nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
          "function takes %d positional arguments but %d were given", expected, given));
  #elif MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_DETAILED
      nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
          "%q() takes %d positional arguments but %d were given",
          mp_obj_fun_get_name(MP_OBJ_FROM_PTR(f)), expected, given));
  #endif
  }
  
  #if DEBUG_PRINT
  STATIC void dump_args(const mp_obj_t *a, size_t sz) {
      DEBUG_printf("%p: ", a);
      for (size_t i = 0; i < sz; i++) {
          DEBUG_printf("%p ", a[i]);
      }
      DEBUG_printf("\n");
  }
  #else
  #define dump_args(...) (void)0
  #endif
  
  // On entry code_state should be allocated somewhere (stack/heap) and
  // contain the following valid entries:
  //    - code_state->ip should contain the offset in bytes from the start of
  //      the bytecode chunk to just after n_state and n_exc_stack
  //    - code_state->n_state should be set to the state size (locals plus stack)
  void mp_setup_code_state(mp_code_state *code_state, mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, const mp_obj_t *args) {
      // This function is pretty complicated.  It's main aim is to be efficient in speed and RAM
      // usage for the common case of positional only args.
      size_t n_state = code_state->n_state;
  
      // ip comes in as an offset into bytecode, so turn it into a true pointer
      code_state->ip = self->bytecode + (size_t)code_state->ip;
  
      // store pointer to constant table
      code_state->const_table = self->const_table;
  
      #if MICROPY_STACKLESS
      code_state->prev = NULL;
      #endif
  
      // get params
      size_t scope_flags = *code_state->ip++;
      size_t n_pos_args = *code_state->ip++;
      size_t n_kwonly_args = *code_state->ip++;
      size_t n_def_pos_args = *code_state->ip++;
  
      code_state->sp = &code_state->state[0] - 1;
      code_state->exc_sp = (mp_exc_stack_t*)(code_state->state + n_state) - 1;
  
      // zero out the local stack to begin with
      memset(code_state->state, 0, n_state * sizeof(*code_state->state));
  
      const mp_obj_t *kwargs = args + n_args;
  
      // var_pos_kw_args points to the stack where the var-args tuple, and var-kw dict, should go (if they are needed)
      mp_obj_t *var_pos_kw_args = &code_state->state[n_state - 1 - n_pos_args - n_kwonly_args];
  
      // check positional arguments
  
      if (n_args > n_pos_args) {
          // given more than enough arguments
          if ((scope_flags & MP_SCOPE_FLAG_VARARGS) == 0) {
              fun_pos_args_mismatch(self, n_pos_args, n_args);
          }
          // put extra arguments in varargs tuple
          *var_pos_kw_args-- = mp_obj_new_tuple(n_args - n_pos_args, args + n_pos_args);
          n_args = n_pos_args;
      } else {
          if ((scope_flags & MP_SCOPE_FLAG_VARARGS) != 0) {
              DEBUG_printf("passing empty tuple as *args\n");
              *var_pos_kw_args-- = mp_const_empty_tuple;
          }
          // Apply processing and check below only if we don't have kwargs,
          // otherwise, kw handling code below has own extensive checks.
          if (n_kw == 0 && (scope_flags & MP_SCOPE_FLAG_DEFKWARGS) == 0) {
              if (n_args >= (size_t)(n_pos_args - n_def_pos_args)) {
                  // given enough arguments, but may need to use some default arguments
                  for (size_t i = n_args; i < n_pos_args; i++) {
                      code_state->state[n_state - 1 - i] = self->extra_args[i - (n_pos_args - n_def_pos_args)];
                  }
              } else {
                  fun_pos_args_mismatch(self, n_pos_args - n_def_pos_args, n_args);
              }
          }
      }
  
      // copy positional args into state
      for (size_t i = 0; i < n_args; i++) {
          code_state->state[n_state - 1 - i] = args[i];
      }
  
      // check keyword arguments
  
      if (n_kw != 0 || (scope_flags & MP_SCOPE_FLAG_DEFKWARGS) != 0) {
          DEBUG_printf("Initial args: ");
          dump_args(code_state->state + n_state - n_pos_args - n_kwonly_args, n_pos_args + n_kwonly_args);
  
          mp_obj_t dict = MP_OBJ_NULL;
          if ((scope_flags & MP_SCOPE_FLAG_VARKEYWORDS) != 0) {
              dict = mp_obj_new_dict(n_kw); // TODO: better go conservative with 0?
              *var_pos_kw_args = dict;
          }
  
          // get pointer to arg_names array
          const mp_obj_t *arg_names = (const mp_obj_t*)code_state->const_table;
  
          for (size_t i = 0; i < n_kw; i++) {
              mp_obj_t wanted_arg_name = kwargs[2 * i];
              for (size_t j = 0; j < n_pos_args + n_kwonly_args; j++) {
                  if (wanted_arg_name == arg_names[j]) {
                      if (code_state->state[n_state - 1 - j] != MP_OBJ_NULL) {
                          nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                              "function got multiple values for argument '%q'", MP_OBJ_QSTR_VALUE(wanted_arg_name)));
                      }
                      code_state->state[n_state - 1 - j] = kwargs[2 * i + 1];
                      goto continue2;
                  }
              }
              // Didn't find name match with positional args
              if ((scope_flags & MP_SCOPE_FLAG_VARKEYWORDS) == 0) {
                  nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError, "function does not take keyword arguments"));
              }
              mp_obj_dict_store(dict, kwargs[2 * i], kwargs[2 * i + 1]);
  continue2:;
          }
  
          DEBUG_printf("Args with kws flattened: ");
          dump_args(code_state->state + n_state - n_pos_args - n_kwonly_args, n_pos_args + n_kwonly_args);
  
          // fill in defaults for positional args
          mp_obj_t *d = &code_state->state[n_state - n_pos_args];
          mp_obj_t *s = &self->extra_args[n_def_pos_args - 1];
          for (size_t i = n_def_pos_args; i > 0; i--, d++, s--) {
              if (*d == MP_OBJ_NULL) {
                  *d = *s;
              }
          }
  
          DEBUG_printf("Args after filling default positional: ");
          dump_args(code_state->state + n_state - n_pos_args - n_kwonly_args, n_pos_args + n_kwonly_args);
  
          // Check that all mandatory positional args are specified
          while (d < &code_state->state[n_state]) {
              if (*d++ == MP_OBJ_NULL) {
                  nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                      "function missing required positional argument #%d", &code_state->state[n_state] - d));
              }
          }
  
          // Check that all mandatory keyword args are specified
          // Fill in default kw args if we have them
          for (size_t i = 0; i < n_kwonly_args; i++) {
              if (code_state->state[n_state - 1 - n_pos_args - i] == MP_OBJ_NULL) {
                  mp_map_elem_t *elem = NULL;
                  if ((scope_flags & MP_SCOPE_FLAG_DEFKWARGS) != 0) {
                      elem = mp_map_lookup(&((mp_obj_dict_t*)MP_OBJ_TO_PTR(self->extra_args[n_def_pos_args]))->map, arg_names[n_pos_args + i], MP_MAP_LOOKUP);
                  }
                  if (elem != NULL) {
                      code_state->state[n_state - 1 - n_pos_args - i] = elem->value;
                  } else {
                      nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                          "function missing required keyword argument '%q'", MP_OBJ_QSTR_VALUE(arg_names[n_pos_args + i])));
                  }
              }
          }
  
      } else {
          // no keyword arguments given
          if (n_kwonly_args != 0) {
              nlr_raise(mp_obj_new_exception_msg(&mp_type_TypeError,
                  "function missing keyword-only argument"));
          }
          if ((scope_flags & MP_SCOPE_FLAG_VARKEYWORDS) != 0) {
              *var_pos_kw_args = mp_obj_new_dict(0);
          }
      }
  
      // get the ip and skip argument names
      const byte *ip = code_state->ip;
  
      // store pointer to code_info and jump over it
      {
          code_state->code_info = ip;
          const byte *ip2 = ip;
          size_t code_info_size = mp_decode_uint(&ip2);
          ip += code_info_size;
      }
  
      // bytecode prelude: initialise closed over variables
      size_t local_num;
      while ((local_num = *ip++) != 255) {
          code_state->state[n_state - 1 - local_num] =
              mp_obj_new_cell(code_state->state[n_state - 1 - local_num]);
      }
  
      // now that we skipped over the prelude, set the ip for the VM
      code_state->ip = ip;
  
      DEBUG_printf("Calling: n_pos_args=%d, n_kwonly_args=%d\n", n_pos_args, n_kwonly_args);
      dump_args(code_state->state + n_state - n_pos_args - n_kwonly_args, n_pos_args + n_kwonly_args);
      dump_args(code_state->state, n_state);
  }
  
  #if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE
  
  // The following table encodes the number of bytes that a specific opcode
  // takes up.  There are 3 special opcodes that always have an extra byte:
  //     MP_BC_MAKE_CLOSURE
  //     MP_BC_MAKE_CLOSURE_DEFARGS
  //     MP_BC_RAISE_VARARGS
  // There are 4 special opcodes that have an extra byte only when
  // MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE is enabled:
  //     MP_BC_LOAD_NAME
  //     MP_BC_LOAD_GLOBAL
  //     MP_BC_LOAD_ATTR
  //     MP_BC_STORE_ATTR
  #define OC4(a, b, c, d) (a | (b << 2) | (c << 4) | (d << 6))
  #define U (0) // undefined opcode
  #define B (MP_OPCODE_BYTE) // single byte
  #define Q (MP_OPCODE_QSTR) // single byte plus 2-byte qstr
  #define V (MP_OPCODE_VAR_UINT) // single byte plus variable encoded unsigned int
  #define O (MP_OPCODE_OFFSET) // single byte plus 2-byte bytecode offset
  STATIC const byte opcode_format_table[64] = {
      OC4(U, U, U, U), // 0x00-0x03
      OC4(U, U, U, U), // 0x04-0x07
      OC4(U, U, U, U), // 0x08-0x0b
      OC4(U, U, U, U), // 0x0c-0x0f
      OC4(B, B, B, U), // 0x10-0x13
      OC4(V, U, Q, V), // 0x14-0x17
      OC4(B, U, V, V), // 0x18-0x1b
      OC4(Q, Q, Q, Q), // 0x1c-0x1f
      OC4(B, B, V, V), // 0x20-0x23
      OC4(Q, Q, Q, B), // 0x24-0x27
      OC4(V, V, Q, Q), // 0x28-0x2b
      OC4(U, U, U, U), // 0x2c-0x2f
      OC4(B, B, B, B), // 0x30-0x33
      OC4(B, O, O, O), // 0x34-0x37
      OC4(O, O, U, U), // 0x38-0x3b
      OC4(U, O, B, O), // 0x3c-0x3f
      OC4(O, B, B, O), // 0x40-0x43
      OC4(B, B, O, B), // 0x44-0x47
      OC4(U, U, U, U), // 0x48-0x4b
      OC4(U, U, U, U), // 0x4c-0x4f
      OC4(V, V, V, V), // 0x50-0x53
      OC4(B, V, V, V), // 0x54-0x57
      OC4(V, V, V, B), // 0x58-0x5b
      OC4(B, B, B, U), // 0x5c-0x5f
      OC4(V, V, V, V), // 0x60-0x63
      OC4(V, V, V, V), // 0x64-0x67
      OC4(Q, Q, B, U), // 0x68-0x6b
      OC4(U, U, U, U), // 0x6c-0x6f
  
      OC4(B, B, B, B), // 0x70-0x73
      OC4(B, B, B, B), // 0x74-0x77
      OC4(B, B, B, B), // 0x78-0x7b
      OC4(B, B, B, B), // 0x7c-0x7f
      OC4(B, B, B, B), // 0x80-0x83
      OC4(B, B, B, B), // 0x84-0x87
      OC4(B, B, B, B), // 0x88-0x8b
      OC4(B, B, B, B), // 0x8c-0x8f
      OC4(B, B, B, B), // 0x90-0x93
      OC4(B, B, B, B), // 0x94-0x97
      OC4(B, B, B, B), // 0x98-0x9b
      OC4(B, B, B, B), // 0x9c-0x9f
      OC4(B, B, B, B), // 0xa0-0xa3
      OC4(B, B, B, B), // 0xa4-0xa7
      OC4(B, B, B, B), // 0xa8-0xab
      OC4(B, B, B, B), // 0xac-0xaf
  
      OC4(B, B, B, B), // 0xb0-0xb3
      OC4(B, B, B, B), // 0xb4-0xb7
      OC4(B, B, B, B), // 0xb8-0xbb
      OC4(B, B, B, B), // 0xbc-0xbf
  
      OC4(B, B, B, B), // 0xc0-0xc3
      OC4(B, B, B, B), // 0xc4-0xc7
      OC4(B, B, B, B), // 0xc8-0xcb
      OC4(B, B, B, B), // 0xcc-0xcf
  
      OC4(B, B, B, B), // 0xd0-0xd3
      OC4(B, B, B, B), // 0xd4-0xd7
      OC4(B, B, B, B), // 0xd8-0xdb
      OC4(B, B, B, B), // 0xdc-0xdf
  
      OC4(B, B, B, B), // 0xe0-0xe3
      OC4(B, B, B, B), // 0xe4-0xe7
      OC4(B, B, B, B), // 0xe8-0xeb
      OC4(B, B, B, B), // 0xec-0xef
  
      OC4(B, B, B, B), // 0xf0-0xf3
      OC4(B, B, B, B), // 0xf4-0xf7
      OC4(B, B, U, U), // 0xf8-0xfb
      OC4(U, U, U, U), // 0xfc-0xff
  };
  #undef OC4
  #undef U
  #undef B
  #undef Q
  #undef V
  #undef O
  
  uint mp_opcode_format(const byte *ip, size_t *opcode_size) {
      uint f = (opcode_format_table[*ip >> 2] >> (2 * (*ip & 3))) & 3;
      const byte *ip_start = ip;
      if (f == MP_OPCODE_QSTR) {
          ip += 3;
      } else {
          int extra_byte = (
              *ip == MP_BC_RAISE_VARARGS
              || *ip == MP_BC_MAKE_CLOSURE
              || *ip == MP_BC_MAKE_CLOSURE_DEFARGS
              #if MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
              || *ip == MP_BC_LOAD_NAME
              || *ip == MP_BC_LOAD_GLOBAL
              || *ip == MP_BC_LOAD_ATTR
              || *ip == MP_BC_STORE_ATTR
              #endif
          );
          ip += 1;
          if (f == MP_OPCODE_VAR_UINT) {
              while ((*ip++ & 0x80) != 0) {
              }
          } else if (f == MP_OPCODE_OFFSET) {
              ip += 2;
          }
          ip += extra_byte;
      }
      *opcode_size = ip - ip_start;
      return f;
  }
  
  #endif // MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE
  