/*
 * 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/runtime.h"
#include "py/bc0.h"
#include "py/bc.h"
#include "py/profile.h"

// *FORMAT-OFF*

#if 0
#define TRACE(ip) printf("sp=%d ", (int)(sp - &code_state->state[0] + 1)); mp_bytecode_print2(ip, 1, code_state->fun_bc->const_table);
#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_PERSISTENT_CODE

#define DECODE_QSTR \
 qstr qst = ip[0] | ip[1] << 8; \
 ip += 2;
#define DECODE_PTR \
 DECODE_UINT; \
 void *ptr = (void*)(uintptr_t)code_state->fun_bc->const_table[unum]
#define DECODE_OBJ \
 DECODE_UINT; \
 mp_obj_t obj = (mp_obj_t)code_state->fun_bc->const_table[unum]

#else

#define DECODE_QSTR qstr qst = 0; \
 do { \
 qst = (qst << 7) + (*ip & 0x7f); \
 } while ((*ip++ & 0x80) != 0)
#define DECODE_PTR \
 ip = (byte*)MP_ALIGN(ip, sizeof(void*)); \
 void *ptr = *(void**)ip; \
 ip += sizeof(void*)
#define DECODE_OBJ \
 ip = (byte*)MP_ALIGN(ip, sizeof(mp_obj_t)); \
 mp_obj_t obj = *(mp_obj_t*)ip; \
 ip += sizeof(mp_obj_t)

#endif

#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

#if MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
static inline mp_map_elem_t *mp_map_cached_lookup(mp_map_t *map, qstr qst, uint8_t *idx_cache) {
 size_t idx = *idx_cache;
 mp_obj_t key = MP_OBJ_NEW_QSTR(qst);
 mp_map_elem_t *elem = NULL;
 if (idx < map->alloc && map->table[idx].key == key) {
 elem = &map->table[idx];
 } else {
 elem = mp_map_lookup(map, key, MP_MAP_LOOKUP);
 if (elem != NULL) {
 *idx_cache = (elem - &map->table[0]) & 0xff;
 }
 }
 return elem;
}
#endif

// 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 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;
 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_int_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;
 }

 #if !MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
 ENTRY(MP_BC_LOAD_NAME): {
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 PUSH(mp_load_name(qst));
 DISPATCH();
 }
 #else
 ENTRY(MP_BC_LOAD_NAME): {
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 mp_map_elem_t *elem = mp_map_cached_lookup(&mp_locals_get()->map, qst, (uint8_t*)ip);
 mp_obj_t obj;
 if (elem != NULL) {
 obj = elem->value;
 } else {
 obj = mp_load_name(qst);
 }
 PUSH(obj);
 ip++;
 DISPATCH();
 }
 #endif

 #if !MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
 ENTRY(MP_BC_LOAD_GLOBAL): {
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 PUSH(mp_load_global(qst));
 DISPATCH();
 }
 #else
 ENTRY(MP_BC_LOAD_GLOBAL): {
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 mp_map_elem_t *elem = mp_map_cached_lookup(&mp_globals_get()->map, qst, (uint8_t*)ip);
 mp_obj_t obj;
 if (elem != NULL) {
 obj = elem->value;
 } else {
 obj = mp_load_global(qst);
 }
 PUSH(obj);
 ip++;
 DISPATCH();
 }
 #endif

 #if !MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
 ENTRY(MP_BC_LOAD_ATTR): {
 FRAME_UPDATE();
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 SET_TOP(mp_load_attr(TOP(), qst));
 DISPATCH();
 }
 #else
 ENTRY(MP_BC_LOAD_ATTR): {
 FRAME_UPDATE();
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 mp_obj_t top = TOP();
 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_cached_lookup(&self->members, qst, (uint8_t*)ip);
 }
 mp_obj_t obj;
 if (elem != NULL) {
 obj = elem->value;
 } else {
 obj = mp_load_attr(top, qst);
 }
 SET_TOP(obj);
 ip++;
 DISPATCH();
 }
 #endif

 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();
 }

 #if !MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
 ENTRY(MP_BC_STORE_ATTR): {
 FRAME_UPDATE();
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 mp_store_attr(sp[0], qst, sp[-1]);
 sp -= 2;
 DISPATCH();
 }
 #else
 // This caching code works with MICROPY_PY_BUILTINS_PROPERTY and/or
 // MICROPY_PY_DESCRIPTORS enabled because if the attr exists in
 // self->members then it can't be a property or have descriptors. A
 // consequence of this is that we can't use MP_MAP_LOOKUP_ADD_IF_NOT_FOUND
 // in the fast-path below, because that store could override a property.
 ENTRY(MP_BC_STORE_ATTR): {
 FRAME_UPDATE();
 MARK_EXC_IP_SELECTIVE();
 DECODE_QSTR;
 mp_map_elem_t *elem = NULL;
 mp_obj_t top = TOP();
 if (mp_obj_is_instance_type(mp_obj_get_type(top)) && sp[-1] != MP_OBJ_NULL) {
 mp_obj_instance_t *self = MP_OBJ_TO_PTR(top);
 elem = mp_map_cached_lookup(&self->members, qst, (uint8_t*)ip);
 }
 if (elem != NULL) {
 elem->value = sp[-1];
 } else {
 mp_store_attr(sp[0], qst, sp[-1]);
 }
 sp -= 2;
 ip++;
 DISPATCH();
 }
 #endif

 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, MP_OBJ_NULL, MP_OBJ_NULL));
 DISPATCH();
 }

 ENTRY(MP_BC_MAKE_FUNCTION_DEFARGS): {
 DECODE_PTR;
 // Stack layout: def_tuple def_dict <- TOS
 mp_obj_t def_dict = POP();
 SET_TOP(mp_make_function_from_raw_code(ptr, TOP(), def_dict));
 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, 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, 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) {
 // Pop exhausted gen
 sp--;
 if (ret_value == MP_OBJ_STOP_ITERATION) {
 // Optimize StopIteration
 // TODO: get StopIteration's value
 PUSH(mp_const_none);
 } else {
 PUSH(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_VM(mp_pending_exception);
 if (obj != MP_OBJ_NULL) {
 MP_STATE_VM(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_VM(mp_pending_exception) != MP_OBJ_NULL) {
 MARK_EXC_IP_SELECTIVE();
 mp_obj_t obj = MP_STATE_VM(mp_pending_exception);
 MP_STATE_VM(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 *bytecode_start = ip + n_info + n_cell;
 #if !MICROPY_PERSISTENT_CODE
 // so bytecode is aligned
 bytecode_start = MP_ALIGN(bytecode_start, sizeof(mp_uint_t));
 #endif
 size_t bc = code_state->ip - bytecode_start;
 #if MICROPY_PERSISTENT_CODE
 qstr block_name = ip[0] | (ip[1] << 8);
 qstr source_file = ip[2] | (ip[3] << 8);
 ip += 4;
 #else
 qstr block_name = mp_decode_uint_value(ip);
 ip = mp_decode_uint_skip(ip);
 qstr source_file = mp_decode_uint_value(ip);
 ip = mp_decode_uint_skip(ip);
 #endif
 size_t source_line = mp_bytecode_get_source_line(ip, 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;
 }
 }
 }
}