text: /*
   * This file is part of the MicroPython project, http://micropython.org/
   *
   * The MIT License (MIT)
   *
   * Copyright (c) 2013-2019 Damien P. George
   * Copyright (c) 2014-2015 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 <stdio.h>
  #include <string.h>
  #include <assert.h>
  
  #include "py/emitglue.h"
  #include "py/objtype.h"
  #include "py/objfun.h"
  #include "py/runtime.h"
  #include "py/bc0.h"
  #include "py/profile.h"
  
  // *FORMAT-OFF*
  
  #if 0
  #if MICROPY_PY_THREAD
  #define TRACE_PREFIX mp_printf(&mp_plat_print, "ts=%p sp=%d ", mp_thread_get_state(), (int)(sp - &code_state->state[0] + 1))
  #else
  #define TRACE_PREFIX mp_printf(&mp_plat_print, "sp=%d ", (int)(sp - &code_state->state[0] + 1))
  #endif
  #define TRACE(ip) TRACE_PREFIX; mp_bytecode_print2(&mp_plat_print, ip, 1, &code_state->fun_bc->context->constants);
  #else
  #define TRACE(ip)
  #endif
  
  // Value stack grows up (this makes it incompatible with native C stack, but
  // makes sure that arguments to functions are in natural order arg1..argN
  // (Python semantics mandates left-to-right evaluation order, including for
  // function arguments). Stack pointer is pre-incremented and points at the
  // top element.
  // Exception stack also grows up, top element is also pointed at.
  
  #define DECODE_UINT \
      mp_uint_t unum = 0; \
      do { \
          unum = (unum << 7) + (*ip & 0x7f); \
      } while ((*ip++ & 0x80) != 0)
  #define DECODE_ULABEL size_t ulab = (ip[0] | (ip[1] << 8)); ip += 2
  #define DECODE_SLABEL size_t slab = (ip[0] | (ip[1] << 8)) - 0x8000; ip += 2
  
  #if MICROPY_EMIT_BYTECODE_USES_QSTR_TABLE
  
  #define DECODE_QSTR \
      DECODE_UINT; \
      qstr qst = qstr_table[unum]
  
  #else
  
  #define DECODE_QSTR \
      DECODE_UINT; \
      qstr qst = unum;
  
  #endif
  
  #define DECODE_PTR \
      DECODE_UINT; \
      void *ptr = (void *)(uintptr_t)code_state->fun_bc->child_table[unum]
  
  #define DECODE_OBJ \
      DECODE_UINT; \
      mp_obj_t obj = (mp_obj_t)code_state->fun_bc->context->constants.obj_table[unum]
  
  #define PUSH(val) *++sp = (val)
  #define POP() (*sp--)
  #define TOP() (*sp)
  #define SET_TOP(val) *sp = (val)
  
  #if MICROPY_PY_SYS_EXC_INFO
  #define CLEAR_SYS_EXC_INFO() MP_STATE_VM(cur_exception) = NULL;
  #else
  #define CLEAR_SYS_EXC_INFO()
  #endif
  
  #define PUSH_EXC_BLOCK(with_or_finally) do { \
      DECODE_ULABEL; /* except labels are always forward */ \
      ++exc_sp; \
      exc_sp->handler = ip + ulab; \
      exc_sp->val_sp = MP_TAGPTR_MAKE(sp, ((with_or_finally) << 1)); \
      exc_sp->prev_exc = NULL; \
  } while (0)
  
  #define POP_EXC_BLOCK() \
      exc_sp--; /* pop back to previous exception handler */ \
      CLEAR_SYS_EXC_INFO() /* just clear sys.exc_info(), not compliant, but it shouldn't be used in 1st place */
  
  #define CANCEL_ACTIVE_FINALLY(sp) do { \
      if (mp_obj_is_small_int(sp[-1])) { \
          /* Stack: (..., prev_dest_ip, prev_cause, dest_ip) */ \
          /* Cancel the unwind through the previous finally, replace with current one */ \
          sp[-2] = sp[0]; \
          sp -= 2; \
      } else { \
          assert(sp[-1] == mp_const_none || mp_obj_is_exception_instance(sp[-1])); \
          /* Stack: (..., None/exception, dest_ip) */ \
          /* Silence the finally's exception value (may be None or an exception) */ \
          sp[-1] = sp[0]; \
          --sp; \
      } \
  } while (0)
  
  #if MICROPY_PY_SYS_SETTRACE
  
  #define FRAME_SETUP() do { \
      assert(code_state != code_state->prev_state); \
      MP_STATE_THREAD(current_code_state) = code_state; \
      assert(code_state != code_state->prev_state); \
  } while(0)
  
  #define FRAME_ENTER() do { \
      assert(code_state != code_state->prev_state); \
      code_state->prev_state = MP_STATE_THREAD(current_code_state); \
      assert(code_state != code_state->prev_state); \
      if (!mp_prof_is_executing) { \
          mp_prof_frame_enter(code_state); \
      } \
  } while(0)
  
  #define FRAME_LEAVE() do { \
      assert(code_state != code_state->prev_state); \
      MP_STATE_THREAD(current_code_state) = code_state->prev_state; \
      assert(code_state != code_state->prev_state); \
  } while(0)
  
  #define FRAME_UPDATE() do { \
      assert(MP_STATE_THREAD(current_code_state) == code_state); \
      if (!mp_prof_is_executing) { \
          code_state->frame = MP_OBJ_TO_PTR(mp_prof_frame_update(code_state)); \
      } \
  } while(0)
  
  #define TRACE_TICK(current_ip, current_sp, is_exception) do { \
      assert(code_state != code_state->prev_state); \
      assert(MP_STATE_THREAD(current_code_state) == code_state); \
      if (!mp_prof_is_executing && code_state->frame && MP_STATE_THREAD(prof_trace_callback)) { \
          MP_PROF_INSTR_DEBUG_PRINT(code_state->ip); \
      } \
      if (!mp_prof_is_executing && code_state->frame && code_state->frame->callback) { \
          mp_prof_instr_tick(code_state, is_exception); \
      } \
  } while(0)
  
  #else // MICROPY_PY_SYS_SETTRACE
  #define FRAME_SETUP()
  #define FRAME_ENTER()
  #define FRAME_LEAVE()
  #define FRAME_UPDATE()
  #define TRACE_TICK(current_ip, current_sp, is_exception)
  #endif // MICROPY_PY_SYS_SETTRACE
  
  // fastn has items in reverse order (fastn[0] is local[0], fastn[-1] is local[1], etc)
  // sp points to bottom of stack which grows up
  // returns:
  //  MP_VM_RETURN_NORMAL, sp valid, return value in *sp
  //  MP_VM_RETURN_YIELD, ip, sp valid, yielded value in *sp
  //  MP_VM_RETURN_EXCEPTION, exception in state[0]
  mp_vm_return_kind_t MICROPY_WRAP_MP_EXECUTE_BYTECODE(mp_execute_bytecode)(mp_code_state_t *code_state, volatile mp_obj_t inject_exc) {
  #define SELECTIVE_EXC_IP (0)
  #if SELECTIVE_EXC_IP
  #define MARK_EXC_IP_SELECTIVE() { code_state->ip = ip; } /* stores ip 1 byte past last opcode */
  #define MARK_EXC_IP_GLOBAL()
  #else
  #define MARK_EXC_IP_SELECTIVE()
  #define MARK_EXC_IP_GLOBAL() { code_state->ip = ip; } /* stores ip pointing to last opcode */
  #endif
  #if MICROPY_OPT_COMPUTED_GOTO
      #include "py/vmentrytable.h"
      #define DISPATCH() do { \
          TRACE(ip); \
          MARK_EXC_IP_GLOBAL(); \
          TRACE_TICK(ip, sp, false); \
          goto *entry_table[*ip++]; \
      } while (0)
      #define DISPATCH_WITH_PEND_EXC_CHECK() goto pending_exception_check
      #define ENTRY(op) entry_##op
      #define ENTRY_DEFAULT entry_default
  #else
      #define DISPATCH() goto dispatch_loop
      #define DISPATCH_WITH_PEND_EXC_CHECK() goto pending_exception_check
      #define ENTRY(op) case op
      #define ENTRY_DEFAULT default
  #endif
  
      // nlr_raise needs to be implemented as a goto, so that the C compiler's flow analyser
      // sees that it's possible for us to jump from the dispatch loop to the exception
      // handler.  Without this, the code may have a different stack layout in the dispatch
      // loop and the exception handler, leading to very obscure bugs.
      #define RAISE(o) do { nlr_pop(); nlr.ret_val = MP_OBJ_TO_PTR(o); goto exception_handler; } while (0)
  
  #if MICROPY_STACKLESS
  run_code_state: ;
  #endif
  FRAME_ENTER();
  
  #if MICROPY_STACKLESS
  run_code_state_from_return: ;
  #endif
  FRAME_SETUP();
  
      // Pointers which are constant for particular invocation of mp_execute_bytecode()
      mp_obj_t * /*const*/ fastn;
      mp_exc_stack_t * /*const*/ exc_stack;
      {
          size_t n_state = code_state->n_state;
          fastn = &code_state->state[n_state - 1];
          exc_stack = (mp_exc_stack_t*)(code_state->state + n_state);
      }
  
      // variables that are visible to the exception handler (declared volatile)
      mp_exc_stack_t *volatile exc_sp = MP_CODE_STATE_EXC_SP_IDX_TO_PTR(exc_stack, code_state->exc_sp_idx); // stack grows up, exc_sp points to top of stack
  
      #if MICROPY_PY_THREAD_GIL && MICROPY_PY_THREAD_GIL_VM_DIVISOR
      // This needs to be volatile and outside the VM loop so it persists across handling
      // of any exceptions.  Otherwise it's possible that the VM never gives up the GIL.
      volatile int gil_divisor = MICROPY_PY_THREAD_GIL_VM_DIVISOR;
      #endif
  
      // outer exception handling loop
      for (;;) {
          nlr_buf_t nlr;
  outer_dispatch_loop:
          if (nlr_push(&nlr) == 0) {
              // local variables that are not visible to the exception handler
              const byte *ip = code_state->ip;
              mp_obj_t *sp = code_state->sp;
              #if MICROPY_EMIT_BYTECODE_USES_QSTR_TABLE
              const qstr_short_t *qstr_table = code_state->fun_bc->context->constants.qstr_table;
              #endif
              mp_obj_t obj_shared;
              MICROPY_VM_HOOK_INIT
  
              // If we have exception to inject, now that we finish setting up
              // execution context, raise it. This works as if MP_BC_RAISE_OBJ
              // bytecode was executed.
              // Injecting exc into yield from generator is a special case,
              // handled by MP_BC_YIELD_FROM itself
              if (inject_exc != MP_OBJ_NULL && *ip != MP_BC_YIELD_FROM) {
                  mp_obj_t exc = inject_exc;
                  inject_exc = MP_OBJ_NULL;
                  exc = mp_make_raise_obj(exc);
                  RAISE(exc);
              }
  
              // loop to execute byte code
              for (;;) {
  dispatch_loop:
  #if MICROPY_OPT_COMPUTED_GOTO
                  DISPATCH();
  #else
                  TRACE(ip);
                  MARK_EXC_IP_GLOBAL();
                  TRACE_TICK(ip, sp, false);
                  switch (*ip++) {
  #endif
  
                  ENTRY(MP_BC_LOAD_CONST_FALSE):
                      PUSH(mp_const_false);
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_CONST_NONE):
                      PUSH(mp_const_none);
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_CONST_TRUE):
                      PUSH(mp_const_true);
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_CONST_SMALL_INT): {
                      mp_uint_t num = 0;
                      if ((ip[0] & 0x40) != 0) {
                          // Number is negative
                          num--;
                      }
                      do {
                          num = (num << 7) | (*ip & 0x7f);
                      } while ((*ip++ & 0x80) != 0);
                      PUSH(MP_OBJ_NEW_SMALL_INT(num));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_CONST_STRING): {
                      DECODE_QSTR;
                      PUSH(MP_OBJ_NEW_QSTR(qst));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_CONST_OBJ): {
                      DECODE_OBJ;
                      PUSH(obj);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_NULL):
                      PUSH(MP_OBJ_NULL);
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_FAST_N): {
                      DECODE_UINT;
                      obj_shared = fastn[-unum];
                      load_check:
                      if (obj_shared == MP_OBJ_NULL) {
                          local_name_error: {
                              MARK_EXC_IP_SELECTIVE();
                              mp_obj_t obj = mp_obj_new_exception_msg(&mp_type_NameError, MP_ERROR_TEXT("local variable referenced before assignment"));
                              RAISE(obj);
                          }
                      }
                      PUSH(obj_shared);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_DEREF): {
                      DECODE_UINT;
                      obj_shared = mp_obj_cell_get(fastn[-unum]);
                      goto load_check;
                  }
  
                  ENTRY(MP_BC_LOAD_NAME): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      PUSH(mp_load_name(qst));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_GLOBAL): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      PUSH(mp_load_global(qst));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_ATTR): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_obj_t top = TOP();
                      mp_obj_t obj;
                      #if MICROPY_OPT_LOAD_ATTR_FAST_PATH
                      // For the specific case of an instance type, it implements .attr
                      // and forwards to its members map. Attribute lookups on instance
                      // types are extremely common, so avoid all the other checks and
                      // calls that normally happen first.
                      mp_map_elem_t *elem = NULL;
                      if (mp_obj_is_instance_type(mp_obj_get_type(top))) {
                          mp_obj_instance_t *self = MP_OBJ_TO_PTR(top);
                          elem = mp_map_lookup(&self->members, MP_OBJ_NEW_QSTR(qst), MP_MAP_LOOKUP);
                      }
                      if (elem) {
                          obj = elem->value;
                      } else
                      #endif
                      {
                          obj = mp_load_attr(top, qst);
                      }
                      SET_TOP(obj);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_METHOD): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_load_method(*sp, qst, sp);
                      sp += 1;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_SUPER_METHOD): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      sp -= 1;
                      mp_load_super_method(qst, sp - 1);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_LOAD_BUILD_CLASS):
                      MARK_EXC_IP_SELECTIVE();
                      PUSH(mp_load_build_class());
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_SUBSCR): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t index = POP();
                      SET_TOP(mp_obj_subscr(TOP(), index, MP_OBJ_SENTINEL));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_FAST_N): {
                      DECODE_UINT;
                      fastn[-unum] = POP();
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_DEREF): {
                      DECODE_UINT;
                      mp_obj_cell_set(fastn[-unum], POP());
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_NAME): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_store_name(qst, POP());
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_GLOBAL): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_store_global(qst, POP());
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_ATTR): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_store_attr(sp[0], qst, sp[-1]);
                      sp -= 2;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_SUBSCR):
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_subscr(sp[-1], sp[0], sp[-2]);
                      sp -= 3;
                      DISPATCH();
  
                  ENTRY(MP_BC_DELETE_FAST): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      if (fastn[-unum] == MP_OBJ_NULL) {
                          goto local_name_error;
                      }
                      fastn[-unum] = MP_OBJ_NULL;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_DELETE_DEREF): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      if (mp_obj_cell_get(fastn[-unum]) == MP_OBJ_NULL) {
                          goto local_name_error;
                      }
                      mp_obj_cell_set(fastn[-unum], MP_OBJ_NULL);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_DELETE_NAME): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_delete_name(qst);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_DELETE_GLOBAL): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_delete_global(qst);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_DUP_TOP): {
                      mp_obj_t top = TOP();
                      PUSH(top);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_DUP_TOP_TWO):
                      sp += 2;
                      sp[0] = sp[-2];
                      sp[-1] = sp[-3];
                      DISPATCH();
  
                  ENTRY(MP_BC_POP_TOP):
                      sp -= 1;
                      DISPATCH();
  
                  ENTRY(MP_BC_ROT_TWO): {
                      mp_obj_t top = sp[0];
                      sp[0] = sp[-1];
                      sp[-1] = top;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_ROT_THREE): {
                      mp_obj_t top = sp[0];
                      sp[0] = sp[-1];
                      sp[-1] = sp[-2];
                      sp[-2] = top;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_JUMP): {
                      DECODE_SLABEL;
                      ip += slab;
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_POP_JUMP_IF_TRUE): {
                      DECODE_SLABEL;
                      if (mp_obj_is_true(POP())) {
                          ip += slab;
                      }
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_POP_JUMP_IF_FALSE): {
                      DECODE_SLABEL;
                      if (!mp_obj_is_true(POP())) {
                          ip += slab;
                      }
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_JUMP_IF_TRUE_OR_POP): {
                      DECODE_SLABEL;
                      if (mp_obj_is_true(TOP())) {
                          ip += slab;
                      } else {
                          sp--;
                      }
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_JUMP_IF_FALSE_OR_POP): {
                      DECODE_SLABEL;
                      if (mp_obj_is_true(TOP())) {
                          sp--;
                      } else {
                          ip += slab;
                      }
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_SETUP_WITH): {
                      MARK_EXC_IP_SELECTIVE();
                      // stack: (..., ctx_mgr)
                      mp_obj_t obj = TOP();
                      mp_load_method(obj, MP_QSTR___exit__, sp);
                      mp_load_method(obj, MP_QSTR___enter__, sp + 2);
                      mp_obj_t ret = mp_call_method_n_kw(0, 0, sp + 2);
                      sp += 1;
                      PUSH_EXC_BLOCK(1);
                      PUSH(ret);
                      // stack: (..., __exit__, ctx_mgr, as_value)
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_WITH_CLEANUP): {
                      MARK_EXC_IP_SELECTIVE();
                      // Arriving here, there's "exception control block" on top of stack,
                      // and __exit__ method (with self) underneath it. Bytecode calls __exit__,
                      // and "deletes" it off stack, shifting "exception control block"
                      // to its place.
                      // The bytecode emitter ensures that there is enough space on the Python
                      // value stack to hold the __exit__ method plus an additional 4 entries.
                      if (TOP() == mp_const_none) {
                          // stack: (..., __exit__, ctx_mgr, None)
                          sp[1] = mp_const_none;
                          sp[2] = mp_const_none;
                          sp -= 2;
                          mp_call_method_n_kw(3, 0, sp);
                          SET_TOP(mp_const_none);
                      } else if (mp_obj_is_small_int(TOP())) {
                          // Getting here there are two distinct cases:
                          //  - unwind return, stack: (..., __exit__, ctx_mgr, ret_val, SMALL_INT(-1))
                          //  - unwind jump, stack:   (..., __exit__, ctx_mgr, dest_ip, SMALL_INT(num_exc))
                          // For both cases we do exactly the same thing.
                          mp_obj_t data = sp[-1];
                          mp_obj_t cause = sp[0];
                          sp[-1] = mp_const_none;
                          sp[0] = mp_const_none;
                          sp[1] = mp_const_none;
                          mp_call_method_n_kw(3, 0, sp - 3);
                          sp[-3] = data;
                          sp[-2] = cause;
                          sp -= 2; // we removed (__exit__, ctx_mgr)
                      } else {
                          assert(mp_obj_is_exception_instance(TOP()));
                          // stack: (..., __exit__, ctx_mgr, exc_instance)
                          // Need to pass (exc_type, exc_instance, None) as arguments to __exit__.
                          sp[1] = sp[0];
                          sp[0] = MP_OBJ_FROM_PTR(mp_obj_get_type(sp[0]));
                          sp[2] = mp_const_none;
                          sp -= 2;
                          mp_obj_t ret_value = mp_call_method_n_kw(3, 0, sp);
                          if (mp_obj_is_true(ret_value)) {
                              // We need to silence/swallow the exception.  This is done
                              // by popping the exception and the __exit__ handler and
                              // replacing it with None, which signals END_FINALLY to just
                              // execute the finally handler normally.
                              SET_TOP(mp_const_none);
                          } else {
                              // We need to re-raise the exception.  We pop __exit__ handler
                              // by copying the exception instance down to the new top-of-stack.
                              sp[0] = sp[3];
                          }
                      }
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_UNWIND_JUMP): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_SLABEL;
                      PUSH((mp_obj_t)(mp_uint_t)(uintptr_t)(ip + slab)); // push destination ip for jump
                      PUSH((mp_obj_t)(mp_uint_t)(*ip)); // push number of exception handlers to unwind (0x80 bit set if we also need to pop stack)
  unwind_jump:;
                      mp_uint_t unum = (mp_uint_t)POP(); // get number of exception handlers to unwind
                      while ((unum & 0x7f) > 0) {
                          unum -= 1;
                          assert(exc_sp >= exc_stack);
  
                          if (MP_TAGPTR_TAG1(exc_sp->val_sp)) {
                              if (exc_sp->handler > ip) {
                                  // Found a finally handler that isn't active; run it.
                                  // Getting here the stack looks like:
                                  //     (..., X, dest_ip)
                                  // where X is pointed to by exc_sp->val_sp and in the case
                                  // of a "with" block contains the context manager info.
                                  assert(&sp[-1] == MP_TAGPTR_PTR(exc_sp->val_sp));
                                  // We're going to run "finally" code as a coroutine
                                  // (not calling it recursively). Set up a sentinel
                                  // on the stack so it can return back to us when it is
                                  // done (when WITH_CLEANUP or END_FINALLY reached).
                                  // The sentinel is the number of exception handlers left to
                                  // unwind, which is a non-negative integer.
                                  PUSH(MP_OBJ_NEW_SMALL_INT(unum));
                                  ip = exc_sp->handler;
                                  goto dispatch_loop;
                              } else {
                                  // Found a finally handler that is already active; cancel it.
                                  CANCEL_ACTIVE_FINALLY(sp);
                              }
                          }
                          POP_EXC_BLOCK();
                      }
                      ip = (const byte*)MP_OBJ_TO_PTR(POP()); // pop destination ip for jump
                      if (unum != 0) {
                          // pop the exhausted iterator
                          sp -= MP_OBJ_ITER_BUF_NSLOTS;
                      }
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_SETUP_EXCEPT):
                  ENTRY(MP_BC_SETUP_FINALLY): {
                      MARK_EXC_IP_SELECTIVE();
                      #if SELECTIVE_EXC_IP
                      PUSH_EXC_BLOCK((code_state->ip[-1] == MP_BC_SETUP_FINALLY) ? 1 : 0);
                      #else
                      PUSH_EXC_BLOCK((code_state->ip[0] == MP_BC_SETUP_FINALLY) ? 1 : 0);
                      #endif
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_END_FINALLY):
                      MARK_EXC_IP_SELECTIVE();
                      // if TOS is None, just pops it and continues
                      // if TOS is an integer, finishes coroutine and returns control to caller
                      // if TOS is an exception, reraises the exception
                      assert(exc_sp >= exc_stack);
                      POP_EXC_BLOCK();
                      if (TOP() == mp_const_none) {
                          sp--;
                      } else if (mp_obj_is_small_int(TOP())) {
                          // We finished "finally" coroutine and now dispatch back
                          // to our caller, based on TOS value
                          mp_int_t cause = MP_OBJ_SMALL_INT_VALUE(POP());
                          if (cause < 0) {
                              // A negative cause indicates unwind return
                              goto unwind_return;
                          } else {
                              // Otherwise it's an unwind jump and we must push as a raw
                              // number the number of exception handlers to unwind
                              PUSH((mp_obj_t)cause);
                              goto unwind_jump;
                          }
                      } else {
                          assert(mp_obj_is_exception_instance(TOP()));
                          RAISE(TOP());
                      }
                      DISPATCH();
  
                  ENTRY(MP_BC_GET_ITER):
                      MARK_EXC_IP_SELECTIVE();
                      SET_TOP(mp_getiter(TOP(), NULL));
                      DISPATCH();
  
                  // An iterator for a for-loop takes MP_OBJ_ITER_BUF_NSLOTS slots on
                  // the Python value stack.  These slots are either used to store the
                  // iterator object itself, or the first slot is MP_OBJ_NULL and
                  // the second slot holds a reference to the iterator object.
                  ENTRY(MP_BC_GET_ITER_STACK): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t obj = TOP();
                      mp_obj_iter_buf_t *iter_buf = (mp_obj_iter_buf_t*)sp;
                      sp += MP_OBJ_ITER_BUF_NSLOTS - 1;
                      obj = mp_getiter(obj, iter_buf);
                      if (obj != MP_OBJ_FROM_PTR(iter_buf)) {
                          // Iterator didn't use the stack so indicate that with MP_OBJ_NULL.
                          sp[-MP_OBJ_ITER_BUF_NSLOTS + 1] = MP_OBJ_NULL;
                          sp[-MP_OBJ_ITER_BUF_NSLOTS + 2] = obj;
                      }
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_FOR_ITER): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
                      code_state->sp = sp;
                      mp_obj_t obj;
                      if (sp[-MP_OBJ_ITER_BUF_NSLOTS + 1] == MP_OBJ_NULL) {
                          obj = sp[-MP_OBJ_ITER_BUF_NSLOTS + 2];
                      } else {
                          obj = MP_OBJ_FROM_PTR(&sp[-MP_OBJ_ITER_BUF_NSLOTS + 1]);
                      }
                      mp_obj_t value = mp_iternext_allow_raise(obj);
                      if (value == MP_OBJ_STOP_ITERATION) {
                          sp -= MP_OBJ_ITER_BUF_NSLOTS; // pop the exhausted iterator
                          ip += ulab; // jump to after for-block
                      } else {
                          PUSH(value); // push the next iteration value
                          #if MICROPY_PY_SYS_SETTRACE
                          // LINE event should trigger for every iteration so invalidate last trigger
                          if (code_state->frame) {
                              code_state->frame->lineno = 0;
                          }
                          #endif
                      }
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_POP_EXCEPT_JUMP): {
                      assert(exc_sp >= exc_stack);
                      POP_EXC_BLOCK();
                      DECODE_ULABEL;
                      ip += ulab;
                      DISPATCH_WITH_PEND_EXC_CHECK();
                  }
  
                  ENTRY(MP_BC_BUILD_TUPLE): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      sp -= unum - 1;
                      SET_TOP(mp_obj_new_tuple(unum, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_BUILD_LIST): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      sp -= unum - 1;
                      SET_TOP(mp_obj_new_list(unum, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_BUILD_MAP): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      PUSH(mp_obj_new_dict(unum));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_STORE_MAP):
                      MARK_EXC_IP_SELECTIVE();
                      sp -= 2;
                      mp_obj_dict_store(sp[0], sp[2], sp[1]);
                      DISPATCH();
  
  #if MICROPY_PY_BUILTINS_SET
                  ENTRY(MP_BC_BUILD_SET): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      sp -= unum - 1;
                      SET_TOP(mp_obj_new_set(unum, sp));
                      DISPATCH();
                  }
  #endif
  
  #if MICROPY_PY_BUILTINS_SLICE
                  ENTRY(MP_BC_BUILD_SLICE): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t step = mp_const_none;
                      if (*ip++ == 3) {
                          // 3-argument slice includes step
                          step = POP();
                      }
                      mp_obj_t stop = POP();
                      mp_obj_t start = TOP();
                      SET_TOP(mp_obj_new_slice(start, stop, step));
                      DISPATCH();
                  }
  #endif
  
                  ENTRY(MP_BC_STORE_COMP): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      mp_obj_t obj = sp[-(unum >> 2)];
                      if ((unum & 3) == 0) {
                          mp_obj_list_append(obj, sp[0]);
                          sp--;
                      } else if (!MICROPY_PY_BUILTINS_SET || (unum & 3) == 1) {
                          mp_obj_dict_store(obj, sp[0], sp[-1]);
                          sp -= 2;
                      #if MICROPY_PY_BUILTINS_SET
                      } else {
                          mp_obj_set_store(obj, sp[0]);
                          sp--;
                      #endif
                      }
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_UNPACK_SEQUENCE): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      mp_unpack_sequence(sp[0], unum, sp);
                      sp += unum - 1;
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_UNPACK_EX): {
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      mp_unpack_ex(sp[0], unum, sp);
                      sp += (unum & 0xff) + ((unum >> 8) & 0xff);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_MAKE_FUNCTION): {
                      DECODE_PTR;
                      PUSH(mp_make_function_from_raw_code(ptr, code_state->fun_bc->context, NULL));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_MAKE_FUNCTION_DEFARGS): {
                      DECODE_PTR;
                      // Stack layout: def_tuple def_dict <- TOS
                      sp -= 1;
                      SET_TOP(mp_make_function_from_raw_code(ptr, code_state->fun_bc->context, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_MAKE_CLOSURE): {
                      DECODE_PTR;
                      size_t n_closed_over = *ip++;
                      // Stack layout: closed_overs <- TOS
                      sp -= n_closed_over - 1;
                      SET_TOP(mp_make_closure_from_raw_code(ptr, code_state->fun_bc->context, n_closed_over, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_MAKE_CLOSURE_DEFARGS): {
                      DECODE_PTR;
                      size_t n_closed_over = *ip++;
                      // Stack layout: def_tuple def_dict closed_overs <- TOS
                      sp -= 2 + n_closed_over - 1;
                      SET_TOP(mp_make_closure_from_raw_code(ptr, code_state->fun_bc->context, 0x100 | n_closed_over, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_CALL_FUNCTION): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      // unum & 0xff == n_positional
                      // (unum >> 8) & 0xff == n_keyword
                      sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe);
                      #if MICROPY_STACKLESS
                      if (mp_obj_get_type(*sp) == &mp_type_fun_bc) {
                          code_state->ip = ip;
                          code_state->sp = sp;
                          code_state->exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_FROM_PTR(exc_stack, exc_sp);
                          mp_code_state_t *new_state = mp_obj_fun_bc_prepare_codestate(*sp, unum & 0xff, (unum >> 8) & 0xff, sp + 1);
                          #if !MICROPY_ENABLE_PYSTACK
                          if (new_state == NULL) {
                              // Couldn't allocate codestate on heap: in the strict case raise
                              // an exception, otherwise just fall through to stack allocation.
                              #if MICROPY_STACKLESS_STRICT
                          deep_recursion_error:
                              mp_raise_recursion_depth();
                              #endif
                          } else
                          #endif
                          {
                              new_state->prev = code_state;
                              code_state = new_state;
                              nlr_pop();
                              goto run_code_state;
                          }
                      }
                      #endif
                      SET_TOP(mp_call_function_n_kw(*sp, unum & 0xff, (unum >> 8) & 0xff, sp + 1));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_CALL_FUNCTION_VAR_KW): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      // unum & 0xff == n_positional
                      // (unum >> 8) & 0xff == n_keyword
                      // We have following stack layout here:
                      // fun arg0 arg1 ... kw0 val0 kw1 val1 ... seq dict <- TOS
                      sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe) + 2;
                      #if MICROPY_STACKLESS
                      if (mp_obj_get_type(*sp) == &mp_type_fun_bc) {
                          code_state->ip = ip;
                          code_state->sp = sp;
                          code_state->exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_FROM_PTR(exc_stack, exc_sp);
  
                          mp_call_args_t out_args;
                          mp_call_prepare_args_n_kw_var(false, unum, sp, &out_args);
  
                          mp_code_state_t *new_state = mp_obj_fun_bc_prepare_codestate(out_args.fun,
                              out_args.n_args, out_args.n_kw, out_args.args);
                          #if !MICROPY_ENABLE_PYSTACK
                          // Freeing args at this point does not follow a LIFO order so only do it if
                          // pystack is not enabled.  For pystack, they are freed when code_state is.
                          mp_nonlocal_free(out_args.args, out_args.n_alloc * sizeof(mp_obj_t));
                          #endif
                          #if !MICROPY_ENABLE_PYSTACK
                          if (new_state == NULL) {
                              // Couldn't allocate codestate on heap: in the strict case raise
                              // an exception, otherwise just fall through to stack allocation.
                              #if MICROPY_STACKLESS_STRICT
                              goto deep_recursion_error;
                              #endif
                          } else
                          #endif
                          {
                              new_state->prev = code_state;
                              code_state = new_state;
                              nlr_pop();
                              goto run_code_state;
                          }
                      }
                      #endif
                      SET_TOP(mp_call_method_n_kw_var(false, unum, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_CALL_METHOD): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      // unum & 0xff == n_positional
                      // (unum >> 8) & 0xff == n_keyword
                      sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe) + 1;
                      #if MICROPY_STACKLESS
                      if (mp_obj_get_type(*sp) == &mp_type_fun_bc) {
                          code_state->ip = ip;
                          code_state->sp = sp;
                          code_state->exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_FROM_PTR(exc_stack, exc_sp);
  
                          size_t n_args = unum & 0xff;
                          size_t n_kw = (unum >> 8) & 0xff;
                          int adjust = (sp[1] == MP_OBJ_NULL) ? 0 : 1;
  
                          mp_code_state_t *new_state = mp_obj_fun_bc_prepare_codestate(*sp, n_args + adjust, n_kw, sp + 2 - adjust);
                          #if !MICROPY_ENABLE_PYSTACK
                          if (new_state == NULL) {
                              // Couldn't allocate codestate on heap: in the strict case raise
                              // an exception, otherwise just fall through to stack allocation.
                              #if MICROPY_STACKLESS_STRICT
                              goto deep_recursion_error;
                              #endif
                          } else
                          #endif
                          {
                              new_state->prev = code_state;
                              code_state = new_state;
                              nlr_pop();
                              goto run_code_state;
                          }
                      }
                      #endif
                      SET_TOP(mp_call_method_n_kw(unum & 0xff, (unum >> 8) & 0xff, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_CALL_METHOD_VAR_KW): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_UINT;
                      // unum & 0xff == n_positional
                      // (unum >> 8) & 0xff == n_keyword
                      // We have following stack layout here:
                      // fun self arg0 arg1 ... kw0 val0 kw1 val1 ... seq dict <- TOS
                      sp -= (unum & 0xff) + ((unum >> 7) & 0x1fe) + 3;
                      #if MICROPY_STACKLESS
                      if (mp_obj_get_type(*sp) == &mp_type_fun_bc) {
                          code_state->ip = ip;
                          code_state->sp = sp;
                          code_state->exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_FROM_PTR(exc_stack, exc_sp);
  
                          mp_call_args_t out_args;
                          mp_call_prepare_args_n_kw_var(true, unum, sp, &out_args);
  
                          mp_code_state_t *new_state = mp_obj_fun_bc_prepare_codestate(out_args.fun,
                              out_args.n_args, out_args.n_kw, out_args.args);
                          #if !MICROPY_ENABLE_PYSTACK
                          // Freeing args at this point does not follow a LIFO order so only do it if
                          // pystack is not enabled.  For pystack, they are freed when code_state is.
                          mp_nonlocal_free(out_args.args, out_args.n_alloc * sizeof(mp_obj_t));
                          #endif
                          #if !MICROPY_ENABLE_PYSTACK
                          if (new_state == NULL) {
                              // Couldn't allocate codestate on heap: in the strict case raise
                              // an exception, otherwise just fall through to stack allocation.
                              #if MICROPY_STACKLESS_STRICT
                              goto deep_recursion_error;
                              #endif
                          } else
                          #endif
                          {
                              new_state->prev = code_state;
                              code_state = new_state;
                              nlr_pop();
                              goto run_code_state;
                          }
                      }
                      #endif
                      SET_TOP(mp_call_method_n_kw_var(true, unum, sp));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_RETURN_VALUE):
                      MARK_EXC_IP_SELECTIVE();
  unwind_return:
                      // Search for and execute finally handlers that aren't already active
                      while (exc_sp >= exc_stack) {
                          if (MP_TAGPTR_TAG1(exc_sp->val_sp)) {
                              if (exc_sp->handler > ip) {
                                  // Found a finally handler that isn't active; run it.
                                  // Getting here the stack looks like:
                                  //     (..., X, [iter0, iter1, ...,] ret_val)
                                  // where X is pointed to by exc_sp->val_sp and in the case
                                  // of a "with" block contains the context manager info.
                                  // There may be 0 or more for-iterators between X and the
                                  // return value, and these must be removed before control can
                                  // pass to the finally code.  We simply copy the ret_value down
                                  // over these iterators, if they exist.  If they don't then the
                                  // following is a null operation.
                                  mp_obj_t *finally_sp = MP_TAGPTR_PTR(exc_sp->val_sp);
                                  finally_sp[1] = sp[0];
                                  sp = &finally_sp[1];
                                  // We're going to run "finally" code as a coroutine
                                  // (not calling it recursively). Set up a sentinel
                                  // on a stack so it can return back to us when it is
                                  // done (when WITH_CLEANUP or END_FINALLY reached).
                                  PUSH(MP_OBJ_NEW_SMALL_INT(-1));
                                  ip = exc_sp->handler;
                                  goto dispatch_loop;
                              } else {
                                  // Found a finally handler that is already active; cancel it.
                                  CANCEL_ACTIVE_FINALLY(sp);
                              }
                          }
                          POP_EXC_BLOCK();
                      }
                      nlr_pop();
                      code_state->sp = sp;
                      assert(exc_sp == exc_stack - 1);
                      MICROPY_VM_HOOK_RETURN
                      #if MICROPY_STACKLESS
                      if (code_state->prev != NULL) {
                          mp_obj_t res = *sp;
                          mp_globals_set(code_state->old_globals);
                          mp_code_state_t *new_code_state = code_state->prev;
                          #if MICROPY_ENABLE_PYSTACK
                          // Free code_state, and args allocated by mp_call_prepare_args_n_kw_var
                          // (The latter is implicitly freed when using pystack due to its LIFO nature.)
                          // The sizeof in the following statement does not include the size of the variable
                          // part of the struct.  This arg is anyway not used if pystack is enabled.
                          mp_nonlocal_free(code_state, sizeof(mp_code_state_t));
                          #endif
                          code_state = new_code_state;
                          *code_state->sp = res;
                          goto run_code_state_from_return;
                      }
                      #endif
                      FRAME_LEAVE();
                      return MP_VM_RETURN_NORMAL;
  
                  ENTRY(MP_BC_RAISE_LAST): {
                      MARK_EXC_IP_SELECTIVE();
                      // search for the inner-most previous exception, to reraise it
                      mp_obj_t obj = MP_OBJ_NULL;
                      for (mp_exc_stack_t *e = exc_sp; e >= exc_stack; --e) {
                          if (e->prev_exc != NULL) {
                              obj = MP_OBJ_FROM_PTR(e->prev_exc);
                              break;
                          }
                      }
                      if (obj == MP_OBJ_NULL) {
                          obj = mp_obj_new_exception_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("no active exception to reraise"));
                      }
                      RAISE(obj);
                  }
  
                  ENTRY(MP_BC_RAISE_OBJ): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t obj = mp_make_raise_obj(TOP());
                      RAISE(obj);
                  }
  
                  ENTRY(MP_BC_RAISE_FROM): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_warning(NULL, "exception chaining not supported");
                      sp--; // ignore (pop) "from" argument
                      mp_obj_t obj = mp_make_raise_obj(TOP());
                      RAISE(obj);
                  }
  
                  ENTRY(MP_BC_YIELD_VALUE):
  yield:
                      nlr_pop();
                      code_state->ip = ip;
                      code_state->sp = sp;
                      code_state->exc_sp_idx = MP_CODE_STATE_EXC_SP_IDX_FROM_PTR(exc_stack, exc_sp);
                      FRAME_LEAVE();
                      return MP_VM_RETURN_YIELD;
  
                  ENTRY(MP_BC_YIELD_FROM): {
                      MARK_EXC_IP_SELECTIVE();
  //#define EXC_MATCH(exc, type) mp_obj_is_type(exc, type)
  #define EXC_MATCH(exc, type) mp_obj_exception_match(exc, type)
  #define GENERATOR_EXIT_IF_NEEDED(t) if (t != MP_OBJ_NULL && EXC_MATCH(t, MP_OBJ_FROM_PTR(&mp_type_GeneratorExit))) { mp_obj_t raise_t = mp_make_raise_obj(t); RAISE(raise_t); }
                      mp_vm_return_kind_t ret_kind;
                      mp_obj_t send_value = POP();
                      mp_obj_t t_exc = MP_OBJ_NULL;
                      mp_obj_t ret_value;
                      code_state->sp = sp; // Save sp because it's needed if mp_resume raises StopIteration
                      if (inject_exc != MP_OBJ_NULL) {
                          t_exc = inject_exc;
                          inject_exc = MP_OBJ_NULL;
                          ret_kind = mp_resume(TOP(), MP_OBJ_NULL, t_exc, &ret_value);
                      } else {
                          ret_kind = mp_resume(TOP(), send_value, MP_OBJ_NULL, &ret_value);
                      }
  
                      if (ret_kind == MP_VM_RETURN_YIELD) {
                          ip--;
                          PUSH(ret_value);
                          goto yield;
                      } else if (ret_kind == MP_VM_RETURN_NORMAL) {
                          // The generator has finished, and returned a value via StopIteration
                          // Replace exhausted generator with the returned value
                          SET_TOP(ret_value);
                          // If we injected GeneratorExit downstream, then even
                          // if it was swallowed, we re-raise GeneratorExit
                          GENERATOR_EXIT_IF_NEEDED(t_exc);
                          DISPATCH();
                      } else {
                          assert(ret_kind == MP_VM_RETURN_EXCEPTION);
                          assert(!EXC_MATCH(ret_value, MP_OBJ_FROM_PTR(&mp_type_StopIteration)));
                          // Pop exhausted gen
                          sp--;
                          RAISE(ret_value);
                      }
                  }
  
                  ENTRY(MP_BC_IMPORT_NAME): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_obj_t obj = POP();
                      SET_TOP(mp_import_name(qst, obj, TOP()));
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_IMPORT_FROM): {
                      FRAME_UPDATE();
                      MARK_EXC_IP_SELECTIVE();
                      DECODE_QSTR;
                      mp_obj_t obj = mp_import_from(TOP(), qst);
                      PUSH(obj);
                      DISPATCH();
                  }
  
                  ENTRY(MP_BC_IMPORT_STAR):
                      MARK_EXC_IP_SELECTIVE();
                      mp_import_all(POP());
                      DISPATCH();
  
  #if MICROPY_OPT_COMPUTED_GOTO
                  ENTRY(MP_BC_LOAD_CONST_SMALL_INT_MULTI):
                      PUSH(MP_OBJ_NEW_SMALL_INT((mp_int_t)ip[-1] - MP_BC_LOAD_CONST_SMALL_INT_MULTI - MP_BC_LOAD_CONST_SMALL_INT_MULTI_EXCESS));
                      DISPATCH();
  
                  ENTRY(MP_BC_LOAD_FAST_MULTI):
                      obj_shared = fastn[MP_BC_LOAD_FAST_MULTI - (mp_int_t)ip[-1]];
                      goto load_check;
  
                  ENTRY(MP_BC_STORE_FAST_MULTI):
                      fastn[MP_BC_STORE_FAST_MULTI - (mp_int_t)ip[-1]] = POP();
                      DISPATCH();
  
                  ENTRY(MP_BC_UNARY_OP_MULTI):
                      MARK_EXC_IP_SELECTIVE();
                      SET_TOP(mp_unary_op(ip[-1] - MP_BC_UNARY_OP_MULTI, TOP()));
                      DISPATCH();
  
                  ENTRY(MP_BC_BINARY_OP_MULTI): {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t rhs = POP();
                      mp_obj_t lhs = TOP();
                      SET_TOP(mp_binary_op(ip[-1] - MP_BC_BINARY_OP_MULTI, lhs, rhs));
                      DISPATCH();
                  }
  
                  ENTRY_DEFAULT:
                      MARK_EXC_IP_SELECTIVE();
  #else
                  ENTRY_DEFAULT:
                      if (ip[-1] < MP_BC_LOAD_CONST_SMALL_INT_MULTI + MP_BC_LOAD_CONST_SMALL_INT_MULTI_NUM) {
                          PUSH(MP_OBJ_NEW_SMALL_INT((mp_int_t)ip[-1] - MP_BC_LOAD_CONST_SMALL_INT_MULTI - MP_BC_LOAD_CONST_SMALL_INT_MULTI_EXCESS));
                          DISPATCH();
                      } else if (ip[-1] < MP_BC_LOAD_FAST_MULTI + MP_BC_LOAD_FAST_MULTI_NUM) {
                          obj_shared = fastn[MP_BC_LOAD_FAST_MULTI - (mp_int_t)ip[-1]];
                          goto load_check;
                      } else if (ip[-1] < MP_BC_STORE_FAST_MULTI + MP_BC_STORE_FAST_MULTI_NUM) {
                          fastn[MP_BC_STORE_FAST_MULTI - (mp_int_t)ip[-1]] = POP();
                          DISPATCH();
                      } else if (ip[-1] < MP_BC_UNARY_OP_MULTI + MP_BC_UNARY_OP_MULTI_NUM) {
                          SET_TOP(mp_unary_op(ip[-1] - MP_BC_UNARY_OP_MULTI, TOP()));
                          DISPATCH();
                      } else if (ip[-1] < MP_BC_BINARY_OP_MULTI + MP_BC_BINARY_OP_MULTI_NUM) {
                          mp_obj_t rhs = POP();
                          mp_obj_t lhs = TOP();
                          SET_TOP(mp_binary_op(ip[-1] - MP_BC_BINARY_OP_MULTI, lhs, rhs));
                          DISPATCH();
                      } else
  #endif
                  {
  
                      mp_obj_t obj = mp_obj_new_exception_msg(&mp_type_NotImplementedError, MP_ERROR_TEXT("opcode"));
                      nlr_pop();
                      code_state->state[0] = obj;
                      FRAME_LEAVE();
                      return MP_VM_RETURN_EXCEPTION;
                  }
  
  #if !MICROPY_OPT_COMPUTED_GOTO
                  } // switch
  #endif
  
  pending_exception_check:
                  MICROPY_VM_HOOK_LOOP
  
                  #if MICROPY_ENABLE_SCHEDULER
                  // This is an inlined variant of mp_handle_pending
                  if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
                      mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
                      // Re-check state is still pending now that we're in the atomic section.
                      if (MP_STATE_VM(sched_state) == MP_SCHED_PENDING) {
                          MARK_EXC_IP_SELECTIVE();
                          mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
                          if (obj != MP_OBJ_NULL) {
                              MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
                              if (!mp_sched_num_pending()) {
                                  MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
                              }
                              MICROPY_END_ATOMIC_SECTION(atomic_state);
                              RAISE(obj);
                          }
                          mp_handle_pending_tail(atomic_state);
                      } else {
                          MICROPY_END_ATOMIC_SECTION(atomic_state);
                      }
                  }
                  #else
                  // This is an inlined variant of mp_handle_pending
                  if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
                      MARK_EXC_IP_SELECTIVE();
                      mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
                      MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
                      RAISE(obj);
                  }
                  #endif
  
                  #if MICROPY_PY_THREAD_GIL
                  #if MICROPY_PY_THREAD_GIL_VM_DIVISOR
                  if (--gil_divisor == 0)
                  #endif
                  {
                      #if MICROPY_PY_THREAD_GIL_VM_DIVISOR
                      gil_divisor = MICROPY_PY_THREAD_GIL_VM_DIVISOR;
                      #endif
                      #if MICROPY_ENABLE_SCHEDULER
                      // can only switch threads if the scheduler is unlocked
                      if (MP_STATE_VM(sched_state) == MP_SCHED_IDLE)
                      #endif
                      {
                      MP_THREAD_GIL_EXIT();
                      MP_THREAD_GIL_ENTER();
                      }
                  }
                  #endif
  
              } // for loop
  
          } else {
  exception_handler:
              // exception occurred
  
              #if MICROPY_PY_SYS_EXC_INFO
              MP_STATE_VM(cur_exception) = nlr.ret_val;
              #endif
  
              #if SELECTIVE_EXC_IP
              // with selective ip, we store the ip 1 byte past the opcode, so move ptr back
              code_state->ip -= 1;
              #endif
  
              if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(((mp_obj_base_t*)nlr.ret_val)->type), MP_OBJ_FROM_PTR(&mp_type_StopIteration))) {
                  if (code_state->ip) {
                      // check if it's a StopIteration within a for block
                      if (*code_state->ip == MP_BC_FOR_ITER) {
                          const byte *ip = code_state->ip + 1;
                          DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
                          code_state->ip = ip + ulab; // jump to after for-block
                          code_state->sp -= MP_OBJ_ITER_BUF_NSLOTS; // pop the exhausted iterator
                          goto outer_dispatch_loop; // continue with dispatch loop
                      } else if (*code_state->ip == MP_BC_YIELD_FROM) {
                          // StopIteration inside yield from call means return a value of
                          // yield from, so inject exception's value as yield from's result
                          // (Instead of stack pop then push we just replace exhausted gen with value)
                          *code_state->sp = mp_obj_exception_get_value(MP_OBJ_FROM_PTR(nlr.ret_val));
                          code_state->ip++; // yield from is over, move to next instruction
                          goto outer_dispatch_loop; // continue with dispatch loop
                      }
                  }
              }
  
              #if MICROPY_PY_SYS_SETTRACE
              // Exceptions are traced here
              if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(((mp_obj_base_t*)nlr.ret_val)->type), MP_OBJ_FROM_PTR(&mp_type_Exception))) {
                  TRACE_TICK(code_state->ip, code_state->sp, true /* yes, it's an exception */);
              }
              #endif
  
  #if MICROPY_STACKLESS
  unwind_loop:
  #endif
              // Set traceback info (file and line number) where the exception occurred, but not for:
              // - constant GeneratorExit object, because it's const
              // - exceptions re-raised by END_FINALLY
              // - exceptions re-raised explicitly by "raise"
              if (nlr.ret_val != &mp_const_GeneratorExit_obj
                  && *code_state->ip != MP_BC_END_FINALLY
                  && *code_state->ip != MP_BC_RAISE_LAST) {
                  const byte *ip = code_state->fun_bc->bytecode;
                  MP_BC_PRELUDE_SIG_DECODE(ip);
                  MP_BC_PRELUDE_SIZE_DECODE(ip);
                  const byte *line_info_top = ip + n_info;
                  const byte *bytecode_start = ip + n_info + n_cell;
                  size_t bc = code_state->ip - bytecode_start;
                  qstr block_name = mp_decode_uint_value(ip);
                  for (size_t i = 0; i < 1 + n_pos_args + n_kwonly_args; ++i) {
                      ip = mp_decode_uint_skip(ip);
                  }
                  #if MICROPY_EMIT_BYTECODE_USES_QSTR_TABLE
                  block_name = code_state->fun_bc->context->constants.qstr_table[block_name];
                  qstr source_file = code_state->fun_bc->context->constants.qstr_table[0];
                  #else
                  qstr source_file = code_state->fun_bc->context->constants.source_file;
                  #endif
                  size_t source_line = mp_bytecode_get_source_line(ip, line_info_top, bc);
                  mp_obj_exception_add_traceback(MP_OBJ_FROM_PTR(nlr.ret_val), source_file, source_line, block_name);
              }
  
              while (exc_sp >= exc_stack && exc_sp->handler <= code_state->ip) {
  
                  // nested exception
  
                  assert(exc_sp >= exc_stack);
  
                  // TODO make a proper message for nested exception
                  // at the moment we are just raising the very last exception (the one that caused the nested exception)
  
                  // move up to previous exception handler
                  POP_EXC_BLOCK();
              }
  
              if (exc_sp >= exc_stack) {
                  // catch exception and pass to byte code
                  code_state->ip = exc_sp->handler;
                  mp_obj_t *sp = MP_TAGPTR_PTR(exc_sp->val_sp);
                  // save this exception in the stack so it can be used in a reraise, if needed
                  exc_sp->prev_exc = nlr.ret_val;
                  // push exception object so it can be handled by bytecode
                  PUSH(MP_OBJ_FROM_PTR(nlr.ret_val));
                  code_state->sp = sp;
  
              #if MICROPY_STACKLESS
              } else if (code_state->prev != NULL) {
                  mp_globals_set(code_state->old_globals);
                  mp_code_state_t *new_code_state = code_state->prev;
                  #if MICROPY_ENABLE_PYSTACK
                  // Free code_state, and args allocated by mp_call_prepare_args_n_kw_var
                  // (The latter is implicitly freed when using pystack due to its LIFO nature.)
                  // The sizeof in the following statement does not include the size of the variable
                  // part of the struct.  This arg is anyway not used if pystack is enabled.
                  mp_nonlocal_free(code_state, sizeof(mp_code_state_t));
                  #endif
                  code_state = new_code_state;
                  size_t n_state = code_state->n_state;
                  fastn = &code_state->state[n_state - 1];
                  exc_stack = (mp_exc_stack_t*)(code_state->state + n_state);
                  // variables that are visible to the exception handler (declared volatile)
                  exc_sp = MP_CODE_STATE_EXC_SP_IDX_TO_PTR(exc_stack, code_state->exc_sp_idx); // stack grows up, exc_sp points to top of stack
                  goto unwind_loop;
  
              #endif
              } else {
                  // propagate exception to higher level
                  // Note: ip and sp don't have usable values at this point
                  code_state->state[0] = MP_OBJ_FROM_PTR(nlr.ret_val); // put exception here because sp is invalid
                  FRAME_LEAVE();
                  return MP_VM_RETURN_EXCEPTION;
              }
          }
      }
  }
  