/*
 * This file is part of the MicroPython project, http://micropython.org/
 *
 * The MIT License (MIT)
 *
 * Copyright (c) 2013, 2014 Damien P. George
 * Copyright (c) 2014-2018 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 <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <assert.h>

#include "py/parsenum.h"
#include "py/compile.h"
#include "py/objstr.h"
#include "py/objtuple.h"
#include "py/objlist.h"
#include "py/objtype.h"
#include "py/objmodule.h"
#include "py/objgenerator.h"
#include "py/smallint.h"
#include "py/runtime.h"
#include "py/builtin.h"
#include "py/stackctrl.h"
#include "py/gc.h"

#if MICROPY_DEBUG_VERBOSE // print debugging info
#define DEBUG_PRINT (1)
#define DEBUG_printf DEBUG_printf
#define DEBUG_OP_printf(...) DEBUG_printf(__VA_ARGS__)
#else // don't print debugging info
#define DEBUG_printf(...) (void)0
#define DEBUG_OP_printf(...) (void)0
#endif

const mp_obj_module_t mp_module___main__ = {
 .base = { &mp_type_module },
 .globals = (mp_obj_dict_t *)&MP_STATE_VM(dict_main),
};

void mp_init(void) {
 qstr_init();

 // no pending exceptions to start with
 MP_STATE_VM(mp_pending_exception) = MP_OBJ_NULL;
 #if MICROPY_ENABLE_SCHEDULER
 MP_STATE_VM(sched_state) = MP_SCHED_IDLE;
 MP_STATE_VM(sched_idx) = 0;
 MP_STATE_VM(sched_len) = 0;
 #endif

 #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
 mp_init_emergency_exception_buf();
 #endif

 #if MICROPY_KBD_EXCEPTION
 // initialise the exception object for raising KeyboardInterrupt
 MP_STATE_VM(mp_kbd_exception).base.type = &mp_type_KeyboardInterrupt;
 MP_STATE_VM(mp_kbd_exception).traceback_alloc = 0;
 MP_STATE_VM(mp_kbd_exception).traceback_len = 0;
 MP_STATE_VM(mp_kbd_exception).traceback_data = NULL;
 MP_STATE_VM(mp_kbd_exception).args = (mp_obj_tuple_t *)&mp_const_empty_tuple_obj;
 #endif

 #if MICROPY_ENABLE_COMPILER
 // optimization disabled by default
 MP_STATE_VM(mp_optimise_value) = 0;
 #if MICROPY_EMIT_NATIVE
 MP_STATE_VM(default_emit_opt) = MP_EMIT_OPT_NONE;
 #endif
 #endif

 // init global module dict
 mp_obj_dict_init(&MP_STATE_VM(mp_loaded_modules_dict), 3);

 // initialise the __main__ module
 mp_obj_dict_init(&MP_STATE_VM(dict_main), 1);
 mp_obj_dict_store(MP_OBJ_FROM_PTR(&MP_STATE_VM(dict_main)), MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));

 // locals = globals for outer module (see Objects/frameobject.c/PyFrame_New())
 mp_locals_set(&MP_STATE_VM(dict_main));
 mp_globals_set(&MP_STATE_VM(dict_main));

 #if MICROPY_CAN_OVERRIDE_BUILTINS
 // start with no extensions to builtins
 MP_STATE_VM(mp_module_builtins_override_dict) = NULL;
 #endif

 #if MICROPY_PERSISTENT_CODE_TRACK_RELOC_CODE
 MP_STATE_VM(track_reloc_code_list) = MP_OBJ_NULL;
 #endif

 #if MICROPY_PY_OS_DUPTERM
 for (size_t i = 0; i < MICROPY_PY_OS_DUPTERM; ++i) {
 MP_STATE_VM(dupterm_objs[i]) = MP_OBJ_NULL;
 }
 #endif

 #if MICROPY_VFS
 // initialise the VFS sub-system
 MP_STATE_VM(vfs_cur) = NULL;
 MP_STATE_VM(vfs_mount_table) = NULL;
 #endif

 #if MICROPY_PY_SYS_ATEXIT
 MP_STATE_VM(sys_exitfunc) = mp_const_none;
 #endif

 #if MICROPY_PY_SYS_SETTRACE
 MP_STATE_THREAD(prof_trace_callback) = MP_OBJ_NULL;
 MP_STATE_THREAD(prof_callback_is_executing) = false;
 MP_STATE_THREAD(current_code_state) = NULL;
 #endif

 #if MICROPY_PY_BLUETOOTH
 MP_STATE_VM(bluetooth) = MP_OBJ_NULL;
 #endif

 #if MICROPY_PY_THREAD_GIL
 mp_thread_mutex_init(&MP_STATE_VM(gil_mutex));
 #endif

 // call port specific initialization if any
 #ifdef MICROPY_PORT_INIT_FUNC
 MICROPY_PORT_INIT_FUNC;
 #endif

 MP_THREAD_GIL_ENTER();
}

void mp_deinit(void) {
 MP_THREAD_GIL_EXIT();

 // call port specific deinitialization if any
 #ifdef MICROPY_PORT_DEINIT_FUNC
 MICROPY_PORT_DEINIT_FUNC;
 #endif

 // mp_obj_dict_free(&dict_main);
 // mp_map_deinit(&MP_STATE_VM(mp_loaded_modules_map));
}

mp_obj_t mp_load_name(qstr qst) {
 // logic: search locals, globals, builtins
 DEBUG_OP_printf("load name %s\n", qstr_str(qst));
 // If we're at the outer scope (locals == globals), dispatch to load_global right away
 if (mp_locals_get() != mp_globals_get()) {
 mp_map_elem_t *elem = mp_map_lookup(&mp_locals_get()->map, MP_OBJ_NEW_QSTR(qst), MP_MAP_LOOKUP);
 if (elem != NULL) {
 return elem->value;
 }
 }
 return mp_load_global(qst);
}

mp_obj_t mp_load_global(qstr qst) {
 // logic: search globals, builtins
 DEBUG_OP_printf("load global %s\n", qstr_str(qst));
 mp_map_elem_t *elem = mp_map_lookup(&mp_globals_get()->map, MP_OBJ_NEW_QSTR(qst), MP_MAP_LOOKUP);
 if (elem == NULL) {
 #if MICROPY_CAN_OVERRIDE_BUILTINS
 if (MP_STATE_VM(mp_module_builtins_override_dict) != NULL) {
 // lookup in additional dynamic table of builtins first
 elem = mp_map_lookup(&MP_STATE_VM(mp_module_builtins_override_dict)->map, MP_OBJ_NEW_QSTR(qst), MP_MAP_LOOKUP);
 if (elem != NULL) {
 return elem->value;
 }
 }
 #endif
 elem = mp_map_lookup((mp_map_t *)&mp_module_builtins_globals.map, MP_OBJ_NEW_QSTR(qst), MP_MAP_LOOKUP);
 if (elem == NULL) {
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_msg(&mp_type_NameError, MP_ERROR_TEXT("name not defined"));
 #else
 mp_raise_msg_varg(&mp_type_NameError, MP_ERROR_TEXT("name '%q' isn't defined"), qst);
 #endif
 }
 }
 return elem->value;
}

mp_obj_t mp_load_build_class(void) {
 DEBUG_OP_printf("load_build_class\n");
 #if MICROPY_CAN_OVERRIDE_BUILTINS
 if (MP_STATE_VM(mp_module_builtins_override_dict) != NULL) {
 // lookup in additional dynamic table of builtins first
 mp_map_elem_t *elem = mp_map_lookup(&MP_STATE_VM(mp_module_builtins_override_dict)->map, MP_OBJ_NEW_QSTR(MP_QSTR___build_class__), MP_MAP_LOOKUP);
 if (elem != NULL) {
 return elem->value;
 }
 }
 #endif
 return MP_OBJ_FROM_PTR(&mp_builtin___build_class___obj);
}

void mp_store_name(qstr qst, mp_obj_t obj) {
 DEBUG_OP_printf("store name %s <- %p\n", qstr_str(qst), obj);
 mp_obj_dict_store(MP_OBJ_FROM_PTR(mp_locals_get()), MP_OBJ_NEW_QSTR(qst), obj);
}

void mp_delete_name(qstr qst) {
 DEBUG_OP_printf("delete name %s\n", qstr_str(qst));
 // TODO convert KeyError to NameError if qst not found
 mp_obj_dict_delete(MP_OBJ_FROM_PTR(mp_locals_get()), MP_OBJ_NEW_QSTR(qst));
}

void mp_store_global(qstr qst, mp_obj_t obj) {
 DEBUG_OP_printf("store global %s <- %p\n", qstr_str(qst), obj);
 mp_obj_dict_store(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(qst), obj);
}

void mp_delete_global(qstr qst) {
 DEBUG_OP_printf("delete global %s\n", qstr_str(qst));
 // TODO convert KeyError to NameError if qst not found
 mp_obj_dict_delete(MP_OBJ_FROM_PTR(mp_globals_get()), MP_OBJ_NEW_QSTR(qst));
}

mp_obj_t mp_unary_op(mp_unary_op_t op, mp_obj_t arg) {
 DEBUG_OP_printf("unary " UINT_FMT " %q %p\n", op, mp_unary_op_method_name[op], arg);

 if (op == MP_UNARY_OP_NOT) {
 // "not x" is the negative of whether "x" is true per Python semantics
 return mp_obj_new_bool(mp_obj_is_true(arg) == 0);
 } else if (mp_obj_is_small_int(arg)) {
 mp_int_t val = MP_OBJ_SMALL_INT_VALUE(arg);
 switch (op) {
 case MP_UNARY_OP_BOOL:
 return mp_obj_new_bool(val != 0);
 case MP_UNARY_OP_HASH:
 return arg;
 case MP_UNARY_OP_POSITIVE:
 case MP_UNARY_OP_INT:
 return arg;
 case MP_UNARY_OP_NEGATIVE:
 // check for overflow
 if (val == MP_SMALL_INT_MIN) {
 return mp_obj_new_int(-val);
 } else {
 return MP_OBJ_NEW_SMALL_INT(-val);
 }
 case MP_UNARY_OP_ABS:
 if (val >= 0) {
 return arg;
 } else if (val == MP_SMALL_INT_MIN) {
 // check for overflow
 return mp_obj_new_int(-val);
 } else {
 return MP_OBJ_NEW_SMALL_INT(-val);
 }
 default:
 assert(op == MP_UNARY_OP_INVERT);
 return MP_OBJ_NEW_SMALL_INT(~val);
 }
 } else if (op == MP_UNARY_OP_HASH && mp_obj_is_str_or_bytes(arg)) {
 // fast path for hashing str/bytes
 GET_STR_HASH(arg, h);
 if (h == 0) {
 GET_STR_DATA_LEN(arg, data, len);
 h = qstr_compute_hash(data, len);
 }
 return MP_OBJ_NEW_SMALL_INT(h);
 } else {
 const mp_obj_type_t *type = mp_obj_get_type(arg);
 if (type->unary_op != NULL) {
 mp_obj_t result = type->unary_op(op, arg);
 if (result != MP_OBJ_NULL) {
 return result;
 }
 }
 // With MP_UNARY_OP_INT, mp_unary_op() becomes a fallback for mp_obj_get_int().
 // In this case provide a more focused error message to not confuse, e.g. chr(1.0)
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 if (op == MP_UNARY_OP_INT) {
 mp_raise_TypeError(MP_ERROR_TEXT("can't convert to int"));
 } else {
 mp_raise_TypeError(MP_ERROR_TEXT("unsupported type for operator"));
 }
 #else
 if (op == MP_UNARY_OP_INT) {
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("can't convert %s to int"), mp_obj_get_type_str(arg));
 } else {
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("unsupported type for %q: '%s'"),
 mp_unary_op_method_name[op], mp_obj_get_type_str(arg));
 }
 #endif
 }
}

mp_obj_t mp_binary_op(mp_binary_op_t op, mp_obj_t lhs, mp_obj_t rhs) {
 DEBUG_OP_printf("binary " UINT_FMT " %q %p %p\n", op, mp_binary_op_method_name[op], lhs, rhs);

 // TODO correctly distinguish inplace operators for mutable objects
 // lookup logic that CPython uses for +=:
 // check for implemented +=
 // then check for implemented +
 // then check for implemented seq.inplace_concat
 // then check for implemented seq.concat
 // then fail
 // note that list does not implement + or +=, so that inplace_concat is reached first for +=

 // deal with is
 if (op == MP_BINARY_OP_IS) {
 return mp_obj_new_bool(lhs == rhs);
 }

 // deal with == and != for all types
 if (op == MP_BINARY_OP_EQUAL || op == MP_BINARY_OP_NOT_EQUAL) {
 // mp_obj_equal_not_equal supports a bunch of shortcuts
 return mp_obj_equal_not_equal(op, lhs, rhs);
 }

 // deal with exception_match for all types
 if (op == MP_BINARY_OP_EXCEPTION_MATCH) {
 // rhs must be issubclass(rhs, BaseException)
 if (mp_obj_is_exception_type(rhs)) {
 if (mp_obj_exception_match(lhs, rhs)) {
 return mp_const_true;
 } else {
 return mp_const_false;
 }
 } else if (mp_obj_is_type(rhs, &mp_type_tuple)) {
 mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(rhs);
 for (size_t i = 0; i < tuple->len; i++) {
 rhs = tuple->items[i];
 if (!mp_obj_is_exception_type(rhs)) {
 goto unsupported_op;
 }
 if (mp_obj_exception_match(lhs, rhs)) {
 return mp_const_true;
 }
 }
 return mp_const_false;
 }
 goto unsupported_op;
 }

 if (mp_obj_is_small_int(lhs)) {
 mp_int_t lhs_val = MP_OBJ_SMALL_INT_VALUE(lhs);
 if (mp_obj_is_small_int(rhs)) {
 mp_int_t rhs_val = MP_OBJ_SMALL_INT_VALUE(rhs);
 // This is a binary operation: lhs_val op rhs_val
 // We need to be careful to handle overflow; see CERT INT32-C
 // Operations that can overflow:
 // + result always fits in mp_int_t, then handled by SMALL_INT check
 // - result always fits in mp_int_t, then handled by SMALL_INT check
 // * checked explicitly
 // / if lhs=MIN and rhs=-1; result always fits in mp_int_t, then handled by SMALL_INT check
 // % if lhs=MIN and rhs=-1; result always fits in mp_int_t, then handled by SMALL_INT check
 // << checked explicitly
 switch (op) {
 case MP_BINARY_OP_OR:
 case MP_BINARY_OP_INPLACE_OR:
 lhs_val |= rhs_val;
 break;
 case MP_BINARY_OP_XOR:
 case MP_BINARY_OP_INPLACE_XOR:
 lhs_val ^= rhs_val;
 break;
 case MP_BINARY_OP_AND:
 case MP_BINARY_OP_INPLACE_AND:
 lhs_val &= rhs_val;
 break;
 case MP_BINARY_OP_LSHIFT:
 case MP_BINARY_OP_INPLACE_LSHIFT: {
 if (rhs_val < 0) {
 // negative shift not allowed
 mp_raise_ValueError(MP_ERROR_TEXT("negative shift count"));
 } else if (rhs_val >= (mp_int_t)BITS_PER_WORD || lhs_val > (MP_SMALL_INT_MAX >> rhs_val) || lhs_val < (MP_SMALL_INT_MIN >> rhs_val)) {
 // left-shift will overflow, so use higher precision integer
 lhs = mp_obj_new_int_from_ll(lhs_val);
 goto generic_binary_op;
 } else {
 // use standard precision
 lhs_val <<= rhs_val;
 }
 break;
 }
 case MP_BINARY_OP_RSHIFT:
 case MP_BINARY_OP_INPLACE_RSHIFT:
 if (rhs_val < 0) {
 // negative shift not allowed
 mp_raise_ValueError(MP_ERROR_TEXT("negative shift count"));
 } else {
 // standard precision is enough for right-shift
 if (rhs_val >= (mp_int_t)BITS_PER_WORD) {
 // Shifting to big amounts is underfined behavior
 // in C and is CPU-dependent; propagate sign bit.
 rhs_val = BITS_PER_WORD - 1;
 }
 lhs_val >>= rhs_val;
 }
 break;
 case MP_BINARY_OP_ADD:
 case MP_BINARY_OP_INPLACE_ADD:
 lhs_val += rhs_val;
 break;
 case MP_BINARY_OP_SUBTRACT:
 case MP_BINARY_OP_INPLACE_SUBTRACT:
 lhs_val -= rhs_val;
 break;
 case MP_BINARY_OP_MULTIPLY:
 case MP_BINARY_OP_INPLACE_MULTIPLY: {

 // If long long type exists and is larger than mp_int_t, then
 // we can use the following code to perform overflow-checked multiplication.
 // Otherwise (eg in x64 case) we must use mp_small_int_mul_overflow.
 #if 0
 // compute result using long long precision
 long long res = (long long)lhs_val * (long long)rhs_val;
 if (res > MP_SMALL_INT_MAX || res < MP_SMALL_INT_MIN) {
 // result overflowed SMALL_INT, so return higher precision integer
 return mp_obj_new_int_from_ll(res);
 } else {
 // use standard precision
 lhs_val = (mp_int_t)res;
 }
 #endif

 if (mp_small_int_mul_overflow(lhs_val, rhs_val)) {
 // use higher precision
 lhs = mp_obj_new_int_from_ll(lhs_val);
 goto generic_binary_op;
 } else {
 // use standard precision
 return MP_OBJ_NEW_SMALL_INT(lhs_val * rhs_val);
 }
 }
 case MP_BINARY_OP_FLOOR_DIVIDE:
 case MP_BINARY_OP_INPLACE_FLOOR_DIVIDE:
 if (rhs_val == 0) {
 goto zero_division;
 }
 lhs_val = mp_small_int_floor_divide(lhs_val, rhs_val);
 break;

 #if MICROPY_PY_BUILTINS_FLOAT
 case MP_BINARY_OP_TRUE_DIVIDE:
 case MP_BINARY_OP_INPLACE_TRUE_DIVIDE:
 if (rhs_val == 0) {
 goto zero_division;
 }
 return mp_obj_new_float((mp_float_t)lhs_val / (mp_float_t)rhs_val);
 #endif

 case MP_BINARY_OP_MODULO:
 case MP_BINARY_OP_INPLACE_MODULO: {
 if (rhs_val == 0) {
 goto zero_division;
 }
 lhs_val = mp_small_int_modulo(lhs_val, rhs_val);
 break;
 }

 case MP_BINARY_OP_POWER:
 case MP_BINARY_OP_INPLACE_POWER:
 if (rhs_val < 0) {
 #if MICROPY_PY_BUILTINS_FLOAT
 return mp_obj_float_binary_op(op, (mp_float_t)lhs_val, rhs);
 #else
 mp_raise_ValueError(MP_ERROR_TEXT("negative power with no float support"));
 #endif
 } else {
 mp_int_t ans = 1;
 while (rhs_val > 0) {
 if (rhs_val & 1) {
 if (mp_small_int_mul_overflow(ans, lhs_val)) {
 goto power_overflow;
 }
 ans *= lhs_val;
 }
 if (rhs_val == 1) {
 break;
 }
 rhs_val /= 2;
 if (mp_small_int_mul_overflow(lhs_val, lhs_val)) {
 goto power_overflow;
 }
 lhs_val *= lhs_val;
 }
 lhs_val = ans;
 }
 break;

 power_overflow:
 // use higher precision
 lhs = mp_obj_new_int_from_ll(MP_OBJ_SMALL_INT_VALUE(lhs));
 goto generic_binary_op;

 case MP_BINARY_OP_DIVMOD: {
 if (rhs_val == 0) {
 goto zero_division;
 }
 // to reduce stack usage we don't pass a temp array of the 2 items
 mp_obj_tuple_t *tuple = MP_OBJ_TO_PTR(mp_obj_new_tuple(2, NULL));
 tuple->items[0] = MP_OBJ_NEW_SMALL_INT(mp_small_int_floor_divide(lhs_val, rhs_val));
 tuple->items[1] = MP_OBJ_NEW_SMALL_INT(mp_small_int_modulo(lhs_val, rhs_val));
 return MP_OBJ_FROM_PTR(tuple);
 }

 case MP_BINARY_OP_LESS:
 return mp_obj_new_bool(lhs_val < rhs_val);
 case MP_BINARY_OP_MORE:
 return mp_obj_new_bool(lhs_val > rhs_val);
 case MP_BINARY_OP_LESS_EQUAL:
 return mp_obj_new_bool(lhs_val <= rhs_val);
 case MP_BINARY_OP_MORE_EQUAL:
 return mp_obj_new_bool(lhs_val >= rhs_val);

 default:
 goto unsupported_op;
 }
 // This is an inlined version of mp_obj_new_int, for speed
 if (MP_SMALL_INT_FITS(lhs_val)) {
 return MP_OBJ_NEW_SMALL_INT(lhs_val);
 } else {
 return mp_obj_new_int_from_ll(lhs_val);
 }
 #if MICROPY_PY_BUILTINS_FLOAT
 } else if (mp_obj_is_float(rhs)) {
 mp_obj_t res = mp_obj_float_binary_op(op, (mp_float_t)lhs_val, rhs);
 if (res == MP_OBJ_NULL) {
 goto unsupported_op;
 } else {
 return res;
 }
 #endif
 #if MICROPY_PY_BUILTINS_COMPLEX
 } else if (mp_obj_is_type(rhs, &mp_type_complex)) {
 mp_obj_t res = mp_obj_complex_binary_op(op, (mp_float_t)lhs_val, 0, rhs);
 if (res == MP_OBJ_NULL) {
 goto unsupported_op;
 } else {
 return res;
 }
 #endif
 }
 }

 // Convert MP_BINARY_OP_IN to MP_BINARY_OP_CONTAINS with swapped args.
 if (op == MP_BINARY_OP_IN) {
 op = MP_BINARY_OP_CONTAINS;
 mp_obj_t temp = lhs;
 lhs = rhs;
 rhs = temp;
 }

 // generic binary_op supplied by type
 const mp_obj_type_t *type;
generic_binary_op:
 type = mp_obj_get_type(lhs);
 if (type->binary_op != NULL) {
 mp_obj_t result = type->binary_op(op, lhs, rhs);
 if (result != MP_OBJ_NULL) {
 return result;
 }
 }

 #if MICROPY_PY_REVERSE_SPECIAL_METHODS
 if (op >= MP_BINARY_OP_OR && op <= MP_BINARY_OP_POWER) {
 mp_obj_t t = rhs;
 rhs = lhs;
 lhs = t;
 op += MP_BINARY_OP_REVERSE_OR - MP_BINARY_OP_OR;
 goto generic_binary_op;
 } else if (op >= MP_BINARY_OP_REVERSE_OR) {
 // Convert __rop__ back to __op__ for error message
 mp_obj_t t = rhs;
 rhs = lhs;
 lhs = t;
 op -= MP_BINARY_OP_REVERSE_OR - MP_BINARY_OP_OR;
 }
 #endif

 if (op == MP_BINARY_OP_CONTAINS) {
 // If type didn't support containment then explicitly walk the iterator.
 // mp_getiter will raise the appropriate exception if lhs is not iterable.
 mp_obj_iter_buf_t iter_buf;
 mp_obj_t iter = mp_getiter(lhs, &iter_buf);
 mp_obj_t next;
 while ((next = mp_iternext(iter)) != MP_OBJ_STOP_ITERATION) {
 if (mp_obj_equal(next, rhs)) {
 return mp_const_true;
 }
 }
 return mp_const_false;
 }

unsupported_op:
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_TypeError(MP_ERROR_TEXT("unsupported type for operator"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("unsupported types for %q: '%s', '%s'"),
 mp_binary_op_method_name[op], mp_obj_get_type_str(lhs), mp_obj_get_type_str(rhs));
 #endif

zero_division:
 mp_raise_msg(&mp_type_ZeroDivisionError, MP_ERROR_TEXT("divide by zero"));
}

mp_obj_t mp_call_function_0(mp_obj_t fun) {
 return mp_call_function_n_kw(fun, 0, 0, NULL);
}

mp_obj_t mp_call_function_1(mp_obj_t fun, mp_obj_t arg) {
 return mp_call_function_n_kw(fun, 1, 0, &arg);
}

mp_obj_t mp_call_function_2(mp_obj_t fun, mp_obj_t arg1, mp_obj_t arg2) {
 mp_obj_t args[2];
 args[0] = arg1;
 args[1] = arg2;
 return mp_call_function_n_kw(fun, 2, 0, args);
}

// args contains, eg: arg0 arg1 key0 value0 key1 value1
mp_obj_t mp_call_function_n_kw(mp_obj_t fun_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 // TODO improve this: fun object can specify its type and we parse here the arguments,
 // passing to the function arrays of fixed and keyword arguments

 DEBUG_OP_printf("calling function %p(n_args=" UINT_FMT ", n_kw=" UINT_FMT ", args=%p)\n", fun_in, n_args, n_kw, args);

 // get the type
 const mp_obj_type_t *type = mp_obj_get_type(fun_in);

 // do the call
 if (type->call != NULL) {
 return type->call(fun_in, n_args, n_kw, args);
 }

 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_TypeError(MP_ERROR_TEXT("object not callable"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("'%s' object isn't callable"), mp_obj_get_type_str(fun_in));
 #endif
}

// args contains: fun self/NULL arg(0) ... arg(n_args-2) arg(n_args-1) kw_key(0) kw_val(0) ... kw_key(n_kw-1) kw_val(n_kw-1)
// if n_args==0 and n_kw==0 then there are only fun and self/NULL
mp_obj_t mp_call_method_n_kw(size_t n_args, size_t n_kw, const mp_obj_t *args) {
 DEBUG_OP_printf("call method (fun=%p, self=%p, n_args=" UINT_FMT ", n_kw=" UINT_FMT ", args=%p)\n", args[0], args[1], n_args, n_kw, args);
 int adjust = (args[1] == MP_OBJ_NULL) ? 0 : 1;
 return mp_call_function_n_kw(args[0], n_args + adjust, n_kw, args + 2 - adjust);
}

// This function only needs to be exposed externally when in stackless mode.
#if !MICROPY_STACKLESS
STATIC
#endif
void mp_call_prepare_args_n_kw_var(bool have_self, size_t n_args_n_kw, const mp_obj_t *args, mp_call_args_t *out_args) {
 mp_obj_t fun = *args++;
 mp_obj_t self = MP_OBJ_NULL;
 if (have_self) {
 self = *args++; // may be MP_OBJ_NULL
 }
 uint n_args = n_args_n_kw & 0xff;
 uint n_kw = (n_args_n_kw >> 8) & 0xff;
 mp_obj_t pos_seq = args[n_args + 2 * n_kw]; // may be MP_OBJ_NULL
 mp_obj_t kw_dict = args[n_args + 2 * n_kw + 1]; // may be MP_OBJ_NULL

 DEBUG_OP_printf("call method var (fun=%p, self=%p, n_args=%u, n_kw=%u, args=%p, seq=%p, dict=%p)\n", fun, self, n_args, n_kw, args, pos_seq, kw_dict);

 // We need to create the following array of objects:
 // args[0 .. n_args] unpacked(pos_seq) args[n_args .. n_args + 2 * n_kw] unpacked(kw_dict)
 // TODO: optimize one day to avoid constructing new arg array? Will be hard.

 // The new args array
 mp_obj_t *args2;
 uint args2_alloc;
 uint args2_len = 0;

 // Try to get a hint for the size of the kw_dict
 uint kw_dict_len = 0;
 if (kw_dict != MP_OBJ_NULL && mp_obj_is_type(kw_dict, &mp_type_dict)) {
 kw_dict_len = mp_obj_dict_len(kw_dict);
 }

 // Extract the pos_seq sequence to the new args array.
 // Note that it can be arbitrary iterator.
 if (pos_seq == MP_OBJ_NULL) {
 // no sequence

 // allocate memory for the new array of args
 args2_alloc = 1 + n_args + 2 * (n_kw + kw_dict_len);
 args2 = mp_nonlocal_alloc(args2_alloc * sizeof(mp_obj_t));

 // copy the self
 if (self != MP_OBJ_NULL) {
 args2[args2_len++] = self;
 }

 // copy the fixed pos args
 mp_seq_copy(args2 + args2_len, args, n_args, mp_obj_t);
 args2_len += n_args;

 } else if (mp_obj_is_type(pos_seq, &mp_type_tuple) || mp_obj_is_type(pos_seq, &mp_type_list)) {
 // optimise the case of a tuple and list

 // get the items
 size_t len;
 mp_obj_t *items;
 mp_obj_get_array(pos_seq, &len, &items);

 // allocate memory for the new array of args
 args2_alloc = 1 + n_args + len + 2 * (n_kw + kw_dict_len);
 args2 = mp_nonlocal_alloc(args2_alloc * sizeof(mp_obj_t));

 // copy the self
 if (self != MP_OBJ_NULL) {
 args2[args2_len++] = self;
 }

 // copy the fixed and variable position args
 mp_seq_cat(args2 + args2_len, args, n_args, items, len, mp_obj_t);
 args2_len += n_args + len;

 } else {
 // generic iterator

 // allocate memory for the new array of args
 args2_alloc = 1 + n_args + 2 * (n_kw + kw_dict_len) + 3;
 args2 = mp_nonlocal_alloc(args2_alloc * sizeof(mp_obj_t));

 // copy the self
 if (self != MP_OBJ_NULL) {
 args2[args2_len++] = self;
 }

 // copy the fixed position args
 mp_seq_copy(args2 + args2_len, args, n_args, mp_obj_t);
 args2_len += n_args;

 // extract the variable position args from the iterator
 mp_obj_iter_buf_t iter_buf;
 mp_obj_t iterable = mp_getiter(pos_seq, &iter_buf);
 mp_obj_t item;
 while ((item = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
 if (args2_len >= args2_alloc) {
 args2 = mp_nonlocal_realloc(args2, args2_alloc * sizeof(mp_obj_t), args2_alloc * 2 * sizeof(mp_obj_t));
 args2_alloc *= 2;
 }
 args2[args2_len++] = item;
 }
 }

 // The size of the args2 array now is the number of positional args.
 uint pos_args_len = args2_len;

 // Copy the fixed kw args.
 mp_seq_copy(args2 + args2_len, args + n_args, 2 * n_kw, mp_obj_t);
 args2_len += 2 * n_kw;

 // Extract (key,value) pairs from kw_dict dictionary and append to args2.
 // Note that it can be arbitrary iterator.
 if (kw_dict == MP_OBJ_NULL) {
 // pass
 } else if (mp_obj_is_type(kw_dict, &mp_type_dict)) {
 // dictionary
 mp_map_t *map = mp_obj_dict_get_map(kw_dict);
 assert(args2_len + 2 * map->used <= args2_alloc); // should have enough, since kw_dict_len is in this case hinted correctly above
 for (size_t i = 0; i < map->alloc; i++) {
 if (mp_map_slot_is_filled(map, i)) {
 // the key must be a qstr, so intern it if it's a string
 mp_obj_t key = map->table[i].key;
 if (!mp_obj_is_qstr(key)) {
 key = mp_obj_str_intern_checked(key);
 }
 args2[args2_len++] = key;
 args2[args2_len++] = map->table[i].value;
 }
 }
 } else {
 // generic mapping:
 // - call keys() to get an iterable of all keys in the mapping
 // - call __getitem__ for each key to get the corresponding value

 // get the keys iterable
 mp_obj_t dest[3];
 mp_load_method(kw_dict, MP_QSTR_keys, dest);
 mp_obj_t iterable = mp_getiter(mp_call_method_n_kw(0, 0, dest), NULL);

 mp_obj_t key;
 while ((key = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
 // expand size of args array if needed
 if (args2_len + 1 >= args2_alloc) {
 uint new_alloc = args2_alloc * 2;
 if (new_alloc < 4) {
 new_alloc = 4;
 }
 args2 = mp_nonlocal_realloc(args2, args2_alloc * sizeof(mp_obj_t), new_alloc * sizeof(mp_obj_t));
 args2_alloc = new_alloc;
 }

 // the key must be a qstr, so intern it if it's a string
 if (!mp_obj_is_qstr(key)) {
 key = mp_obj_str_intern_checked(key);
 }

 // get the value corresponding to the key
 mp_load_method(kw_dict, MP_QSTR___getitem__, dest);
 dest[2] = key;
 mp_obj_t value = mp_call_method_n_kw(1, 0, dest);

 // store the key/value pair in the argument array
 args2[args2_len++] = key;
 args2[args2_len++] = value;
 }
 }

 out_args->fun = fun;
 out_args->args = args2;
 out_args->n_args = pos_args_len;
 out_args->n_kw = (args2_len - pos_args_len) / 2;
 out_args->n_alloc = args2_alloc;
}

mp_obj_t mp_call_method_n_kw_var(bool have_self, size_t n_args_n_kw, const mp_obj_t *args) {
 mp_call_args_t out_args;
 mp_call_prepare_args_n_kw_var(have_self, n_args_n_kw, args, &out_args);

 mp_obj_t res = mp_call_function_n_kw(out_args.fun, out_args.n_args, out_args.n_kw, out_args.args);
 mp_nonlocal_free(out_args.args, out_args.n_alloc * sizeof(mp_obj_t));

 return res;
}

// unpacked items are stored in reverse order into the array pointed to by items
void mp_unpack_sequence(mp_obj_t seq_in, size_t num, mp_obj_t *items) {
 size_t seq_len;
 if (mp_obj_is_type(seq_in, &mp_type_tuple) || mp_obj_is_type(seq_in, &mp_type_list)) {
 mp_obj_t *seq_items;
 mp_obj_get_array(seq_in, &seq_len, &seq_items);
 if (seq_len < num) {
 goto too_short;
 } else if (seq_len > num) {
 goto too_long;
 }
 for (size_t i = 0; i < num; i++) {
 items[i] = seq_items[num - 1 - i];
 }
 } else {
 mp_obj_iter_buf_t iter_buf;
 mp_obj_t iterable = mp_getiter(seq_in, &iter_buf);

 for (seq_len = 0; seq_len < num; seq_len++) {
 mp_obj_t el = mp_iternext(iterable);
 if (el == MP_OBJ_STOP_ITERATION) {
 goto too_short;
 }
 items[num - 1 - seq_len] = el;
 }
 if (mp_iternext(iterable) != MP_OBJ_STOP_ITERATION) {
 goto too_long;
 }
 }
 return;

too_short:
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_ValueError(MP_ERROR_TEXT("wrong number of values to unpack"));
 #else
 mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("need more than %d values to unpack"), (int)seq_len);
 #endif
too_long:
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_ValueError(MP_ERROR_TEXT("wrong number of values to unpack"));
 #else
 mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("too many values to unpack (expected %d)"), (int)num);
 #endif
}

// unpacked items are stored in reverse order into the array pointed to by items
void mp_unpack_ex(mp_obj_t seq_in, size_t num_in, mp_obj_t *items) {
 size_t num_left = num_in & 0xff;
 size_t num_right = (num_in >> 8) & 0xff;
 DEBUG_OP_printf("unpack ex " UINT_FMT " " UINT_FMT "\n", num_left, num_right);
 size_t seq_len;
 if (mp_obj_is_type(seq_in, &mp_type_tuple) || mp_obj_is_type(seq_in, &mp_type_list)) {
 // Make the seq variable volatile so the compiler keeps a reference to it,
 // since if it's a tuple then seq_items points to the interior of the GC cell
 // and mp_obj_new_list may trigger a GC which doesn't trace this and reclaims seq.
 volatile mp_obj_t seq = seq_in;
 mp_obj_t *seq_items;
 mp_obj_get_array(seq, &seq_len, &seq_items);
 if (seq_len < num_left + num_right) {
 goto too_short;
 }
 for (size_t i = 0; i < num_right; i++) {
 items[i] = seq_items[seq_len - 1 - i];
 }
 items[num_right] = mp_obj_new_list(seq_len - num_left - num_right, seq_items + num_left);
 for (size_t i = 0; i < num_left; i++) {
 items[num_right + 1 + i] = seq_items[num_left - 1 - i];
 }
 seq = MP_OBJ_NULL;
 } else {
 // Generic iterable; this gets a bit messy: we unpack known left length to the
 // items destination array, then the rest to a dynamically created list. Once the
 // iterable is exhausted, we take from this list for the right part of the items.
 // TODO Improve to waste less memory in the dynamically created list.
 mp_obj_t iterable = mp_getiter(seq_in, NULL);
 mp_obj_t item;
 for (seq_len = 0; seq_len < num_left; seq_len++) {
 item = mp_iternext(iterable);
 if (item == MP_OBJ_STOP_ITERATION) {
 goto too_short;
 }
 items[num_left + num_right + 1 - 1 - seq_len] = item;
 }
 mp_obj_list_t *rest = MP_OBJ_TO_PTR(mp_obj_new_list(0, NULL));
 while ((item = mp_iternext(iterable)) != MP_OBJ_STOP_ITERATION) {
 mp_obj_list_append(MP_OBJ_FROM_PTR(rest), item);
 }
 if (rest->len < num_right) {
 goto too_short;
 }
 items[num_right] = MP_OBJ_FROM_PTR(rest);
 for (size_t i = 0; i < num_right; i++) {
 items[num_right - 1 - i] = rest->items[rest->len - num_right + i];
 }
 mp_obj_list_set_len(MP_OBJ_FROM_PTR(rest), rest->len - num_right);
 }
 return;

too_short:
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_ValueError(MP_ERROR_TEXT("wrong number of values to unpack"));
 #else
 mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("need more than %d values to unpack"), (int)seq_len);
 #endif
}

mp_obj_t mp_load_attr(mp_obj_t base, qstr attr) {
 DEBUG_OP_printf("load attr %p.%s\n", base, qstr_str(attr));
 // use load_method
 mp_obj_t dest[2];
 mp_load_method(base, attr, dest);
 if (dest[1] == MP_OBJ_NULL) {
 // load_method returned just a normal attribute
 return dest[0];
 } else {
 // load_method returned a method, so build a bound method object
 return mp_obj_new_bound_meth(dest[0], dest[1]);
 }
}

#if MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG

// The following "checked fun" type is local to the mp_convert_member_lookup
// function, and serves to check that the first argument to a builtin function
// has the correct type.

typedef struct _mp_obj_checked_fun_t {
 mp_obj_base_t base;
 const mp_obj_type_t *type;
 mp_obj_t fun;
} mp_obj_checked_fun_t;

STATIC mp_obj_t checked_fun_call(mp_obj_t self_in, size_t n_args, size_t n_kw, const mp_obj_t *args) {
 mp_obj_checked_fun_t *self = MP_OBJ_TO_PTR(self_in);
 if (n_args > 0) {
 const mp_obj_type_t *arg0_type = mp_obj_get_type(args[0]);
 if (arg0_type != self->type) {
 #if MICROPY_ERROR_REPORTING != MICROPY_ERROR_REPORTING_DETAILED
 mp_raise_TypeError(MP_ERROR_TEXT("argument has wrong type"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("argument should be a '%q' not a '%q'"), self->type->name, arg0_type->name);
 #endif
 }
 }
 return mp_call_function_n_kw(self->fun, n_args, n_kw, args);
}

STATIC const mp_obj_type_t mp_type_checked_fun = {
 { &mp_type_type },
 .flags = MP_TYPE_FLAG_BINDS_SELF,
 .name = MP_QSTR_function,
 .call = checked_fun_call,
};

STATIC mp_obj_t mp_obj_new_checked_fun(const mp_obj_type_t *type, mp_obj_t fun) {
 mp_obj_checked_fun_t *o = m_new_obj(mp_obj_checked_fun_t);
 o->base.type = &mp_type_checked_fun;
 o->type = type;
 o->fun = fun;
 return MP_OBJ_FROM_PTR(o);
}

#endif // MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG

// Given a member that was extracted from an instance, convert it correctly
// and put the result in the dest[] array for a possible method call.
// Conversion means dealing with static/class methods, callables, and values.
// see http://docs.python.org/3/howto/descriptor.html
// and also https://mail.python.org/pipermail/python-dev/2015-March/138950.html
void mp_convert_member_lookup(mp_obj_t self, const mp_obj_type_t *type, mp_obj_t member, mp_obj_t *dest) {
 if (mp_obj_is_obj(member)) {
 const mp_obj_type_t *m_type = ((mp_obj_base_t *)MP_OBJ_TO_PTR(member))->type;
 if (m_type->flags & MP_TYPE_FLAG_BINDS_SELF) {
 // `member` is a function that binds self as its first argument.
 if (m_type->flags & MP_TYPE_FLAG_BUILTIN_FUN) {
 // `member` is a built-in function, which has special behaviour.
 if (mp_obj_is_instance_type(type)) {
 // Built-in functions on user types always behave like a staticmethod.
 dest[0] = member;
 }
 #if MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG
 else if (self == MP_OBJ_NULL && type != &mp_type_object) {
 // `member` is a built-in method without a first argument, so wrap
 // it in a type checker that will check self when it's supplied.
 // Note that object will do its own checking so shouldn't be wrapped.
 dest[0] = mp_obj_new_checked_fun(type, member);
 }
 #endif
 else {
 // Return a (built-in) bound method, with self being this object.
 dest[0] = member;
 dest[1] = self;
 }
 } else {
 // Return a bound method, with self being this object.
 dest[0] = member;
 dest[1] = self;
 }
 } else if (m_type == &mp_type_staticmethod) {
 // `member` is a staticmethod, return the function that it wraps.
 dest[0] = ((mp_obj_static_class_method_t *)MP_OBJ_TO_PTR(member))->fun;
 } else if (m_type == &mp_type_classmethod) {
 // `member` is a classmethod, return a bound method with self being the type of
 // this object. This type should be the type of the original instance, not the
 // base type (which is what is passed in the `type` argument to this function).
 if (self != MP_OBJ_NULL) {
 type = mp_obj_get_type(self);
 }
 dest[0] = ((mp_obj_static_class_method_t *)MP_OBJ_TO_PTR(member))->fun;
 dest[1] = MP_OBJ_FROM_PTR(type);
 } else {
 // `member` is a value, so just return that value.
 dest[0] = member;
 }
 } else {
 // `member` is a value, so just return that value.
 dest[0] = member;
 }
}

// no attribute found, returns: dest[0] == MP_OBJ_NULL, dest[1] == MP_OBJ_NULL
// normal attribute found, returns: dest[0] == <attribute>, dest[1] == MP_OBJ_NULL
// method attribute found, returns: dest[0] == <method>, dest[1] == <self>
void mp_load_method_maybe(mp_obj_t obj, qstr attr, mp_obj_t *dest) {
 // clear output to indicate no attribute/method found yet
 dest[0] = MP_OBJ_NULL;
 dest[1] = MP_OBJ_NULL;

 // get the type
 const mp_obj_type_t *type = mp_obj_get_type(obj);

 // look for built-in names
 #if MICROPY_CPYTHON_COMPAT
 if (attr == MP_QSTR___class__) {
 // a.__class__ is equivalent to type(a)
 dest[0] = MP_OBJ_FROM_PTR(type);
 return;
 }
 #endif

 if (attr == MP_QSTR___next__ && type->iternext != NULL) {
 dest[0] = MP_OBJ_FROM_PTR(&mp_builtin_next_obj);
 dest[1] = obj;

 } else if (type->attr != NULL) {
 // this type can do its own load, so call it
 type->attr(obj, attr, dest);

 } else if (type->locals_dict != NULL) {
 // generic method lookup
 // this is a lookup in the object (ie not class or type)
 assert(type->locals_dict->base.type == &mp_type_dict); // MicroPython restriction, for now
 mp_map_t *locals_map = &type->locals_dict->map;
 mp_map_elem_t *elem = mp_map_lookup(locals_map, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
 if (elem != NULL) {
 mp_convert_member_lookup(obj, type, elem->value, dest);
 }
 }
}

void mp_load_method(mp_obj_t base, qstr attr, mp_obj_t *dest) {
 DEBUG_OP_printf("load method %p.%s\n", base, qstr_str(attr));

 mp_load_method_maybe(base, attr, dest);

 if (dest[0] == MP_OBJ_NULL) {
 // no attribute/method called attr
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_msg(&mp_type_AttributeError, MP_ERROR_TEXT("no such attribute"));
 #else
 // following CPython, we give a more detailed error message for type objects
 if (mp_obj_is_type(base, &mp_type_type)) {
 mp_raise_msg_varg(&mp_type_AttributeError,
 MP_ERROR_TEXT("type object '%q' has no attribute '%q'"),
 ((mp_obj_type_t *)MP_OBJ_TO_PTR(base))->name, attr);
 } else {
 mp_raise_msg_varg(&mp_type_AttributeError,
 MP_ERROR_TEXT("'%s' object has no attribute '%q'"),
 mp_obj_get_type_str(base), attr);
 }
 #endif
 }
}

// Acts like mp_load_method_maybe but catches AttributeError, and all other exceptions if requested
void mp_load_method_protected(mp_obj_t obj, qstr attr, mp_obj_t *dest, bool catch_all_exc) {
 nlr_buf_t nlr;
 if (nlr_push(&nlr) == 0) {
 mp_load_method_maybe(obj, attr, dest);
 nlr_pop();
 } else {
 if (!catch_all_exc
 && !mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(((mp_obj_base_t *)nlr.ret_val)->type),
 MP_OBJ_FROM_PTR(&mp_type_AttributeError))) {
 // Re-raise the exception
 nlr_raise(MP_OBJ_FROM_PTR(nlr.ret_val));
 }
 }
}

void mp_store_attr(mp_obj_t base, qstr attr, mp_obj_t value) {
 DEBUG_OP_printf("store attr %p.%s <- %p\n", base, qstr_str(attr), value);
 const mp_obj_type_t *type = mp_obj_get_type(base);
 if (type->attr != NULL) {
 mp_obj_t dest[2] = {MP_OBJ_SENTINEL, value};
 type->attr(base, attr, dest);
 if (dest[0] == MP_OBJ_NULL) {
 // success
 return;
 }
 }
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_msg(&mp_type_AttributeError, MP_ERROR_TEXT("no such attribute"));
 #else
 mp_raise_msg_varg(&mp_type_AttributeError,
 MP_ERROR_TEXT("'%s' object has no attribute '%q'"),
 mp_obj_get_type_str(base), attr);
 #endif
}

mp_obj_t mp_getiter(mp_obj_t o_in, mp_obj_iter_buf_t *iter_buf) {
 assert(o_in);
 const mp_obj_type_t *type = mp_obj_get_type(o_in);

 // Check for native getiter which is the identity. We handle this case explicitly
 // so we don't unnecessarily allocate any RAM for the iter_buf, which won't be used.
 if (type->getiter == mp_identity_getiter) {
 return o_in;
 }

 // check for native getiter (corresponds to __iter__)
 if (type->getiter != NULL) {
 if (iter_buf == NULL && type->getiter != mp_obj_instance_getiter) {
 // if caller did not provide a buffer then allocate one on the heap
 // mp_obj_instance_getiter is special, it will allocate only if needed
 iter_buf = m_new_obj(mp_obj_iter_buf_t);
 }
 mp_obj_t iter = type->getiter(o_in, iter_buf);
 if (iter != MP_OBJ_NULL) {
 return iter;
 }
 }

 // check for __getitem__
 mp_obj_t dest[2];
 mp_load_method_maybe(o_in, MP_QSTR___getitem__, dest);
 if (dest[0] != MP_OBJ_NULL) {
 // __getitem__ exists, create and return an iterator
 if (iter_buf == NULL) {
 // if caller did not provide a buffer then allocate one on the heap
 iter_buf = m_new_obj(mp_obj_iter_buf_t);
 }
 return mp_obj_new_getitem_iter(dest, iter_buf);
 }

 // object not iterable
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_TypeError(MP_ERROR_TEXT("object not iterable"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("'%s' object isn't iterable"), mp_obj_get_type_str(o_in));
 #endif

}

// may return MP_OBJ_STOP_ITERATION as an optimisation instead of raise StopIteration()
// may also raise StopIteration()
mp_obj_t mp_iternext_allow_raise(mp_obj_t o_in) {
 const mp_obj_type_t *type = mp_obj_get_type(o_in);
 if (type->iternext != NULL) {
 return type->iternext(o_in);
 } else {
 // check for __next__ method
 mp_obj_t dest[2];
 mp_load_method_maybe(o_in, MP_QSTR___next__, dest);
 if (dest[0] != MP_OBJ_NULL) {
 // __next__ exists, call it and return its result
 return mp_call_method_n_kw(0, 0, dest);
 } else {
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_TypeError(MP_ERROR_TEXT("object not an iterator"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("'%s' object isn't an iterator"), mp_obj_get_type_str(o_in));
 #endif
 }
 }
}

// will always return MP_OBJ_STOP_ITERATION instead of raising StopIteration() (or any subclass thereof)
// may raise other exceptions
mp_obj_t mp_iternext(mp_obj_t o_in) {
 MP_STACK_CHECK(); // enumerate, filter, map and zip can recursively call mp_iternext
 const mp_obj_type_t *type = mp_obj_get_type(o_in);
 if (type->iternext != NULL) {
 return type->iternext(o_in);
 } else {
 // check for __next__ method
 mp_obj_t dest[2];
 mp_load_method_maybe(o_in, MP_QSTR___next__, dest);
 if (dest[0] != MP_OBJ_NULL) {
 // __next__ exists, call it and return its result
 nlr_buf_t nlr;
 if (nlr_push(&nlr) == 0) {
 mp_obj_t ret = mp_call_method_n_kw(0, 0, dest);
 nlr_pop();
 return ret;
 } else {
 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))) {
 return MP_OBJ_STOP_ITERATION;
 } else {
 nlr_jump(nlr.ret_val);
 }
 }
 } else {
 #if MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE
 mp_raise_TypeError(MP_ERROR_TEXT("object not an iterator"));
 #else
 mp_raise_msg_varg(&mp_type_TypeError,
 MP_ERROR_TEXT("'%s' object isn't an iterator"), mp_obj_get_type_str(o_in));
 #endif
 }
 }
}

// TODO: Unclear what to do with StopIterarion exception here.
mp_vm_return_kind_t mp_resume(mp_obj_t self_in, mp_obj_t send_value, mp_obj_t throw_value, mp_obj_t *ret_val) {
 assert((send_value != MP_OBJ_NULL) ^ (throw_value != MP_OBJ_NULL));
 const mp_obj_type_t *type = mp_obj_get_type(self_in);

 if (type == &mp_type_gen_instance) {
 return mp_obj_gen_resume(self_in, send_value, throw_value, ret_val);
 }

 if (type->iternext != NULL && send_value == mp_const_none) {
 mp_obj_t ret = type->iternext(self_in);
 *ret_val = ret;
 if (ret != MP_OBJ_STOP_ITERATION) {
 return MP_VM_RETURN_YIELD;
 } else {
 // Emulate raise StopIteration()
 // Special case, handled in vm.c
 return MP_VM_RETURN_NORMAL;
 }
 }

 mp_obj_t dest[3]; // Reserve slot for send() arg

 // Python instance iterator protocol
 if (send_value == mp_const_none) {
 mp_load_method_maybe(self_in, MP_QSTR___next__, dest);
 if (dest[0] != MP_OBJ_NULL) {
 *ret_val = mp_call_method_n_kw(0, 0, dest);
 return MP_VM_RETURN_YIELD;
 }
 }

 // Either python instance generator protocol, or native object
 // generator protocol.
 if (send_value != MP_OBJ_NULL) {
 mp_load_method(self_in, MP_QSTR_send, dest);
 dest[2] = send_value;
 *ret_val = mp_call_method_n_kw(1, 0, dest);
 return MP_VM_RETURN_YIELD;
 }

 assert(throw_value != MP_OBJ_NULL);
 {
 if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(mp_obj_get_type(throw_value)), MP_OBJ_FROM_PTR(&mp_type_GeneratorExit))) {
 mp_load_method_maybe(self_in, MP_QSTR_close, dest);
 if (dest[0] != MP_OBJ_NULL) {
 // TODO: Exceptions raised in close() are not propagated,
 // printed to sys.stderr
 *ret_val = mp_call_method_n_kw(0, 0, dest);
 // We assume one can't "yield" from close()
 return MP_VM_RETURN_NORMAL;
 }
 } else {
 mp_load_method_maybe(self_in, MP_QSTR_throw, dest);
 if (dest[0] != MP_OBJ_NULL) {
 dest[2] = throw_value;
 *ret_val = mp_call_method_n_kw(1, 0, dest);
 // If .throw() method returned, we assume it's value to yield
 // - any exception would be thrown with nlr_raise().
 return MP_VM_RETURN_YIELD;
 }
 }
 // If there's nowhere to throw exception into, then we assume that object
 // is just incapable to handle it, so any exception thrown into it
 // will be propagated up. This behavior is approved by test_pep380.py
 // test_delegation_of_close_to_non_generator(),
 // test_delegating_throw_to_non_generator()
 if (mp_obj_exception_match(throw_value, MP_OBJ_FROM_PTR(&mp_type_StopIteration))) {
 // PEP479: if StopIteration is raised inside a generator it is replaced with RuntimeError
 *ret_val = mp_obj_new_exception_msg(&mp_type_RuntimeError, MP_ERROR_TEXT("generator raised StopIteration"));
 } else {
 *ret_val = mp_make_raise_obj(throw_value);
 }
 return MP_VM_RETURN_EXCEPTION;
 }
}

mp_obj_t mp_make_raise_obj(mp_obj_t o) {
 DEBUG_printf("raise %p\n", o);
 if (mp_obj_is_exception_type(o)) {
 // o is an exception type (it is derived from BaseException (or is BaseException))
 // create and return a new exception instance by calling o
 // TODO could have an option to disable traceback, then builtin exceptions (eg TypeError)
 // could have const instances in ROM which we return here instead
 return mp_call_function_n_kw(o, 0, 0, NULL);
 } else if (mp_obj_is_exception_instance(o)) {
 // o is an instance of an exception, so use it as the exception
 return o;
 } else {
 // o cannot be used as an exception, so return a type error (which will be raised by the caller)
 return mp_obj_new_exception_msg(&mp_type_TypeError, MP_ERROR_TEXT("exceptions must derive from BaseException"));
 }
}

mp_obj_t mp_import_name(qstr name, mp_obj_t fromlist, mp_obj_t level) {
 DEBUG_printf("import name '%s' level=%d\n", qstr_str(name), MP_OBJ_SMALL_INT_VALUE(level));

 // build args array
 mp_obj_t args[5];
 args[0] = MP_OBJ_NEW_QSTR(name);
 args[1] = mp_const_none; // TODO should be globals
 args[2] = mp_const_none; // TODO should be locals
 args[3] = fromlist;
 args[4] = level;

 #if MICROPY_CAN_OVERRIDE_BUILTINS
 // Lookup __import__ and call that if it exists
 mp_obj_dict_t *bo_dict = MP_STATE_VM(mp_module_builtins_override_dict);
 if (bo_dict != NULL) {
 mp_map_elem_t *import = mp_map_lookup(&bo_dict->map, MP_OBJ_NEW_QSTR(MP_QSTR___import__), MP_MAP_LOOKUP);
 if (import != NULL) {
 return mp_call_function_n_kw(import->value, 5, 0, args);
 }
 }
 #endif

 return mp_builtin___import__(5, args);
}

mp_obj_t mp_import_from(mp_obj_t module, qstr name) {
 DEBUG_printf("import from %p %s\n", module, qstr_str(name));

 mp_obj_t dest[2];

 mp_load_method_maybe(module, name, dest);

 if (dest[1] != MP_OBJ_NULL) {
 // Hopefully we can't import bound method from an object
 import_error:
 mp_raise_msg_varg(&mp_type_ImportError, MP_ERROR_TEXT("can't import name %q"), name);
 }

 if (dest[0] != MP_OBJ_NULL) {
 return dest[0];
 }

 #if MICROPY_ENABLE_EXTERNAL_IMPORT

 // See if it's a package, then can try FS import
 if (!mp_obj_is_package(module)) {
 goto import_error;
 }

 mp_load_method_maybe(module, MP_QSTR___name__, dest);
 size_t pkg_name_len;
 const char *pkg_name = mp_obj_str_get_data(dest[0], &pkg_name_len);

 const uint dot_name_len = pkg_name_len + 1 + qstr_len(name);
 char *dot_name = mp_local_alloc(dot_name_len);
 memcpy(dot_name, pkg_name, pkg_name_len);
 dot_name[pkg_name_len] = '.';
 memcpy(dot_name + pkg_name_len + 1, qstr_str(name), qstr_len(name));
 qstr dot_name_q = qstr_from_strn(dot_name, dot_name_len);
 mp_local_free(dot_name);

 // For fromlist, pass sentinel "non empty" value to force returning of leaf module
 return mp_import_name(dot_name_q, mp_const_true, MP_OBJ_NEW_SMALL_INT(0));

 #else

 // Package import not supported with external imports disabled
 goto import_error;

 #endif
}

void mp_import_all(mp_obj_t module) {
 DEBUG_printf("import all %p\n", module);

 // TODO: Support __all__
 mp_map_t *map = &mp_obj_module_get_globals(module)->map;
 for (size_t i = 0; i < map->alloc; i++) {
 if (mp_map_slot_is_filled(map, i)) {
 // Entry in module global scope may be generated programmatically
 // (and thus be not a qstr for longer names). Avoid turning it in
 // qstr if it has '_' and was used exactly to save memory.
 const char *name = mp_obj_str_get_str(map->table[i].key);
 if (*name != '_') {
 qstr qname = mp_obj_str_get_qstr(map->table[i].key);
 mp_store_name(qname, map->table[i].value);
 }
 }
 }
}

#if MICROPY_ENABLE_COMPILER

mp_obj_t mp_parse_compile_execute(mp_lexer_t *lex, mp_parse_input_kind_t parse_input_kind, mp_obj_dict_t *globals, mp_obj_dict_t *locals) {
 // save context
 mp_obj_dict_t *volatile old_globals = mp_globals_get();
 mp_obj_dict_t *volatile old_locals = mp_locals_get();

 // set new context
 mp_globals_set(globals);
 mp_locals_set(locals);

 nlr_buf_t nlr;
 if (nlr_push(&nlr) == 0) {
 qstr source_name = lex->source_name;
 mp_parse_tree_t parse_tree = mp_parse(lex, parse_input_kind);
 mp_obj_t module_fun = mp_compile(&parse_tree, source_name, parse_input_kind == MP_PARSE_SINGLE_INPUT);

 mp_obj_t ret;
 if (MICROPY_PY_BUILTINS_COMPILE && globals == NULL) {
 // for compile only, return value is the module function
 ret = module_fun;
 } else {
 // execute module function and get return value
 ret = mp_call_function_0(module_fun);
 }

 // finish nlr block, restore context and return value
 nlr_pop();
 mp_globals_set(old_globals);
 mp_locals_set(old_locals);
 return ret;
 } else {
 // exception; restore context and re-raise same exception
 mp_globals_set(old_globals);
 mp_locals_set(old_locals);
 nlr_jump(nlr.ret_val);
 }
}

#endif // MICROPY_ENABLE_COMPILER

NORETURN void m_malloc_fail(size_t num_bytes) {
 DEBUG_printf("memory allocation failed, allocating %u bytes\n", (uint)num_bytes);
 #if MICROPY_ENABLE_GC
 if (gc_is_locked()) {
 mp_raise_msg(&mp_type_MemoryError, MP_ERROR_TEXT("memory allocation failed, heap is locked"));
 }
 #endif
 mp_raise_msg_varg(&mp_type_MemoryError,
 MP_ERROR_TEXT("memory allocation failed, allocating %u bytes"), (uint)num_bytes);
}

NORETURN void mp_raise_msg(const mp_obj_type_t *exc_type, mp_rom_error_text_t msg) {
 if (msg == NULL) {
 nlr_raise(mp_obj_new_exception(exc_type));
 } else {
 nlr_raise(mp_obj_new_exception_msg(exc_type, msg));
 }
}

NORETURN void mp_raise_msg_varg(const mp_obj_type_t *exc_type, mp_rom_error_text_t fmt, ...) {
 va_list args;
 va_start(args, fmt);
 mp_obj_t exc = mp_obj_new_exception_msg_vlist(exc_type, fmt, args);
 va_end(args);
 nlr_raise(exc);
}

NORETURN void mp_raise_ValueError(mp_rom_error_text_t msg) {
 mp_raise_msg(&mp_type_ValueError, msg);
}

NORETURN void mp_raise_TypeError(mp_rom_error_text_t msg) {
 mp_raise_msg(&mp_type_TypeError, msg);
}

NORETURN void mp_raise_OSError(int errno_) {
 nlr_raise(mp_obj_new_exception_arg1(&mp_type_OSError, MP_OBJ_NEW_SMALL_INT(errno_)));
}

NORETURN void mp_raise_NotImplementedError(mp_rom_error_text_t msg) {
 mp_raise_msg(&mp_type_NotImplementedError, msg);
}

#if MICROPY_STACK_CHECK || MICROPY_ENABLE_PYSTACK
NORETURN void mp_raise_recursion_depth(void) {
 nlr_raise(mp_obj_new_exception_arg1(&mp_type_RuntimeError,
 MP_OBJ_NEW_QSTR(MP_QSTR_maximum_space_recursion_space_depth_space_exceeded)));
}
#endif