py/emitglue.c - lite/micropython - Linaro Git Browser

 /*
  * This file is part of the Micro Python project, http://micropython.org/
  *
  * The MIT License (MIT)
  *
  * Copyright (c) 2013, 2014 Damien P. George
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
  * in the Software without restriction, including without limitation the rights
  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  * copies of the Software, and to permit persons to whom the Software is
  * furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  * THE SOFTWARE.
  */

 // This code glues the code emitters to the runtime.

 #include <stdint.h>
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>

 #include "py/emitglue.h"
 #include "py/runtime0.h"
 #include "py/bc.h"

 #if 0 // print debugging info
 #define DEBUG_PRINT (1)
 #define WRITE_CODE (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

 #if MICROPY_DEBUG_PRINTERS
 mp_uint_t mp_verbose_flag = 0;
 #endif

 struct _mp_raw_code_t {
     mp_raw_code_kind_t kind : 3;
     mp_uint_t scope_flags : 7;
     mp_uint_t n_pos_args : 11;
     union {
         struct {
             const byte *bytecode;
             const mp_uint_t *const_table;
             #if MICROPY_PERSISTENT_CODE_SAVE
             mp_uint_t bc_len;
             uint16_t n_obj;
             uint16_t n_raw_code;
             #endif
         } u_byte;
         struct {
             void *fun_data;
             const mp_uint_t *const_table;
             mp_uint_t type_sig; // for viper, compressed as 2-bit types; ret is MSB, then arg0, arg1, etc
         } u_native;
     } data;
 };

 mp_raw_code_t *mp_emit_glue_new_raw_code(void) {
     mp_raw_code_t *rc = m_new0(mp_raw_code_t, 1);
     rc->kind = MP_CODE_RESERVED;
     return rc;
 }

 void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, const byte *code, mp_uint_t len,
     const mp_uint_t *const_table,
     #if MICROPY_PERSISTENT_CODE_SAVE
     uint16_t n_obj, uint16_t n_raw_code,
     #endif
     mp_uint_t scope_flags) {

     rc->kind = MP_CODE_BYTECODE;
     rc->scope_flags = scope_flags;
     rc->data.u_byte.bytecode = code;
     rc->data.u_byte.const_table = const_table;
     #if MICROPY_PERSISTENT_CODE_SAVE
     rc->data.u_byte.bc_len = len;
     rc->data.u_byte.n_obj = n_obj;
     rc->data.u_byte.n_raw_code = n_raw_code;
     #endif

 #ifdef DEBUG_PRINT
     DEBUG_printf("assign byte code: code=%p len=" UINT_FMT " flags=%x\n", code, len, (uint)scope_flags);
 #endif
 #if MICROPY_DEBUG_PRINTERS
     if (mp_verbose_flag >= 2) {
         mp_bytecode_print(rc, code, len, const_table);
     }
 #endif
 }

 #if MICROPY_EMIT_NATIVE || MICROPY_EMIT_INLINE_THUMB
 void mp_emit_glue_assign_native(mp_raw_code_t *rc, mp_raw_code_kind_t kind, void *fun_data, mp_uint_t fun_len, const mp_uint_t *const_table, mp_uint_t n_pos_args, mp_uint_t scope_flags, mp_uint_t type_sig) {
     assert(kind == MP_CODE_NATIVE_PY || kind == MP_CODE_NATIVE_VIPER || kind == MP_CODE_NATIVE_ASM);
     rc->kind = kind;
     rc->scope_flags = scope_flags;
     rc->n_pos_args = n_pos_args;
     rc->data.u_native.fun_data = fun_data;
     rc->data.u_native.const_table = const_table;
     rc->data.u_native.type_sig = type_sig;

 #ifdef DEBUG_PRINT
     DEBUG_printf("assign native: kind=%d fun=%p len=" UINT_FMT " n_pos_args=" UINT_FMT " flags=%x\n", kind, fun_data, fun_len, n_pos_args, (uint)scope_flags);
     for (mp_uint_t i = 0; i < fun_len; i++) {
         if (i > 0 && i % 16 == 0) {
             DEBUG_printf("\n");
         }
         DEBUG_printf(" %02x", ((byte*)fun_data)[i]);
     }
     DEBUG_printf("\n");

 #ifdef WRITE_CODE
     FILE *fp_write_code = fopen("out-code", "wb");
     fwrite(fun_data, fun_len, 1, fp_write_code);
     fclose(fp_write_code);
 #endif
 #else
     (void)fun_len;
 #endif
 }
 #endif

 mp_obj_t mp_make_function_from_raw_code(mp_raw_code_t *rc, mp_obj_t def_args, mp_obj_t def_kw_args) {
     DEBUG_OP_printf("make_function_from_raw_code %p\n", rc);
     assert(rc != NULL);

     // def_args must be MP_OBJ_NULL or a tuple
     assert(def_args == MP_OBJ_NULL || MP_OBJ_IS_TYPE(def_args, &mp_type_tuple));

     // def_kw_args must be MP_OBJ_NULL or a dict
     assert(def_kw_args == MP_OBJ_NULL || MP_OBJ_IS_TYPE(def_kw_args, &mp_type_dict));

     // make the function, depending on the raw code kind
     mp_obj_t fun;
     switch (rc->kind) {
         case MP_CODE_BYTECODE:
         no_other_choice:
             fun = mp_obj_new_fun_bc(def_args, def_kw_args, rc->data.u_byte.bytecode, rc->data.u_byte.const_table);
             break;
         #if MICROPY_EMIT_NATIVE
         case MP_CODE_NATIVE_PY:
             fun = mp_obj_new_fun_native(def_args, def_kw_args, rc->data.u_native.fun_data, rc->data.u_native.const_table);
             break;
         case MP_CODE_NATIVE_VIPER:
             fun = mp_obj_new_fun_viper(rc->n_pos_args, rc->data.u_native.fun_data, rc->data.u_native.type_sig);
             break;
         #endif
         #if MICROPY_EMIT_INLINE_THUMB
         case MP_CODE_NATIVE_ASM:
             fun = mp_obj_new_fun_asm(rc->n_pos_args, rc->data.u_native.fun_data, rc->data.u_native.type_sig);
             break;
         #endif
         default:
             // raw code was never set (this should not happen)
             assert(0);
             goto no_other_choice; // to help flow control analysis
     }

     // check for generator functions and if so wrap in generator object
     if ((rc->scope_flags & MP_SCOPE_FLAG_GENERATOR) != 0) {
         fun = mp_obj_new_gen_wrap(fun);
     }

     return fun;
 }

 mp_obj_t mp_make_closure_from_raw_code(mp_raw_code_t *rc, mp_uint_t n_closed_over, const mp_obj_t *args) {
     DEBUG_OP_printf("make_closure_from_raw_code %p " UINT_FMT " %p\n", rc, n_closed_over, args);
     // make function object
     mp_obj_t ffun;
     if (n_closed_over & 0x100) {
         // default positional and keyword args given
         ffun = mp_make_function_from_raw_code(rc, args[0], args[1]);
     } else {
         // default positional and keyword args not given
         ffun = mp_make_function_from_raw_code(rc, MP_OBJ_NULL, MP_OBJ_NULL);
     }
     // wrap function in closure object
     return mp_obj_new_closure(ffun, n_closed_over & 0xff, args + ((n_closed_over >> 7) & 2));
 }

 #if MICROPY_PERSISTENT_CODE

 #include "py/smallint.h"

 // The feature flags byte encodes the compile-time config options that
 // affect the generate bytecode.
 #define MPY_FEATURE_FLAGS ( \
     ((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE) << 0) \
     | ((MICROPY_PY_BUILTINS_STR_UNICODE) << 1) \
     )
 // This is a version of the flags that can be configured at runtime.
 #define MPY_FEATURE_FLAGS_DYNAMIC ( \
     ((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE_DYNAMIC) << 0) \
     | ((MICROPY_PY_BUILTINS_STR_UNICODE_DYNAMIC) << 1) \
     )

 #if MICROPY_PERSISTENT_CODE_LOAD || (MICROPY_PERSISTENT_CODE_SAVE && !MICROPY_DYNAMIC_COMPILER)
 // The bytecode will depend on the number of bits in a small-int, and
 // this function computes that (could make it a fixed constant, but it
 // would need to be defined in mpconfigport.h).
 STATIC int mp_small_int_bits(void) {
     mp_int_t i = MP_SMALL_INT_MAX;
     int n = 1;
     while (i != 0) {
         i >>= 1;
         ++n;
     }
     return n;
 }
 #endif

 typedef struct _bytecode_prelude_t {
     uint n_state;
     uint n_exc_stack;
     uint scope_flags;
     uint n_pos_args;
     uint n_kwonly_args;
     uint n_def_pos_args;
     uint code_info_size;
 } bytecode_prelude_t;

 // ip will point to start of opcodes
 // ip2 will point to simple_name, source_file qstrs
 STATIC void extract_prelude(const byte **ip, const byte **ip2, bytecode_prelude_t *prelude) {
     prelude->n_state = mp_decode_uint(ip);
     prelude->n_exc_stack = mp_decode_uint(ip);
     prelude->scope_flags = *(*ip)++;
     prelude->n_pos_args = *(*ip)++;
     prelude->n_kwonly_args = *(*ip)++;
     prelude->n_def_pos_args = *(*ip)++;
     *ip2 = *ip;
     prelude->code_info_size = mp_decode_uint(ip2);
     *ip += prelude->code_info_size;
     while (*(*ip)++ != 255) {
     }
 }

 #endif // MICROPY_PERSISTENT_CODE

 #if MICROPY_PERSISTENT_CODE_LOAD

 #include "py/parsenum.h"
 #include "py/bc0.h"

 STATIC int read_byte(mp_reader_t *reader) {
     return reader->read_byte(reader->data);
 }

 STATIC void read_bytes(mp_reader_t *reader, byte *buf, size_t len) {
     while (len-- > 0) {
         *buf++ = reader->read_byte(reader->data);
     }
 }

 STATIC mp_uint_t read_uint(mp_reader_t *reader) {
     mp_uint_t unum = 0;
     for (;;) {
         byte b = reader->read_byte(reader->data);
         unum = (unum << 7) | (b & 0x7f);
         if ((b & 0x80) == 0) {
             break;
         }
     }
     return unum;
 }

 STATIC qstr load_qstr(mp_reader_t *reader) {
     mp_uint_t len = read_uint(reader);
     char *str = m_new(char, len);
     read_bytes(reader, (byte*)str, len);
     qstr qst = qstr_from_strn(str, len);
     m_del(char, str, len);
     return qst;
 }

 STATIC mp_obj_t load_obj(mp_reader_t *reader) {
     byte obj_type = read_byte(reader);
     if (obj_type == 'e') {
         return MP_OBJ_FROM_PTR(&mp_const_ellipsis_obj);
     } else {
         size_t len = read_uint(reader);
         vstr_t vstr;
         vstr_init_len(&vstr, len);
         read_bytes(reader, (byte*)vstr.buf, len);
         if (obj_type == 's' || obj_type == 'b') {
             return mp_obj_new_str_from_vstr(obj_type == 's' ? &mp_type_str : &mp_type_bytes, &vstr);
         } else if (obj_type == 'i') {
             return mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
         } else {
             assert(obj_type == 'f' || obj_type == 'c');
             return mp_parse_num_decimal(vstr.buf, vstr.len, obj_type == 'c', false, NULL);
         }
     }
 }

 STATIC void load_bytecode_qstrs(mp_reader_t *reader, byte *ip, byte *ip_top) {
     while (ip < ip_top) {
         size_t sz;
         uint f = mp_opcode_format(ip, &sz);
         if (f == MP_OPCODE_QSTR) {
             qstr qst = load_qstr(reader);
             ip[1] = qst;
             ip[2] = qst >> 8;
         }
         ip += sz;
     }
 }

 STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
     // load bytecode
     mp_uint_t bc_len = read_uint(reader);
     byte *bytecode = m_new(byte, bc_len);
     read_bytes(reader, bytecode, bc_len);

     // extract prelude
     const byte *ip = bytecode;
     const byte *ip2;
     bytecode_prelude_t prelude;
     extract_prelude(&ip, &ip2, &prelude);

     // load qstrs and link global qstr ids into bytecode
     qstr simple_name = load_qstr(reader);
     qstr source_file = load_qstr(reader);
     ((byte*)ip2)[0] = simple_name; ((byte*)ip2)[1] = simple_name >> 8;
     ((byte*)ip2)[2] = source_file; ((byte*)ip2)[3] = source_file >> 8;
     load_bytecode_qstrs(reader, (byte*)ip, bytecode + bc_len);

     // load constant table
     mp_uint_t n_obj = read_uint(reader);
     mp_uint_t n_raw_code = read_uint(reader);
     mp_uint_t *const_table = m_new(mp_uint_t, prelude.n_pos_args + prelude.n_kwonly_args + n_obj + n_raw_code);
     mp_uint_t *ct = const_table;
     for (mp_uint_t i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
         *ct++ = (mp_uint_t)MP_OBJ_NEW_QSTR(load_qstr(reader));
     }
     for (mp_uint_t i = 0; i < n_obj; ++i) {
         *ct++ = (mp_uint_t)load_obj(reader);
     }
     for (mp_uint_t i = 0; i < n_raw_code; ++i) {
         *ct++ = (mp_uint_t)(uintptr_t)load_raw_code(reader);
     }

     // create raw_code and return it
     mp_raw_code_t *rc = mp_emit_glue_new_raw_code();
     mp_emit_glue_assign_bytecode(rc, bytecode, bc_len, const_table,
         #if MICROPY_PERSISTENT_CODE_SAVE
         n_obj, n_raw_code,
         #endif
         prelude.scope_flags);
     return rc;
 }

 mp_raw_code_t *mp_raw_code_load(mp_reader_t *reader) {
     byte header[4];
     read_bytes(reader, header, sizeof(header));
     if (strncmp((char*)header, "M\x00", 2) != 0) {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
             "invalid .mpy file"));
     }
     if (header[2] != MPY_FEATURE_FLAGS || header[3] > mp_small_int_bits()) {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
             "incompatible .mpy file"));
     }
     return load_raw_code(reader);
 }

 typedef struct _mp_mem_reader_t {
     const byte *cur;
     const byte *end;
 } mp_mem_reader_t;

 STATIC mp_uint_t mp_mem_reader_next_byte(void *br_in) {
     mp_mem_reader_t *br = br_in;
     if (br->cur < br->end) {
         return *br->cur++;
     } else {
         return (mp_uint_t)-1;
     }
 }

 mp_raw_code_t *mp_raw_code_load_mem(const byte *buf, size_t len) {
     mp_mem_reader_t mr = {buf, buf + len};
     mp_reader_t reader = {&mr, mp_mem_reader_next_byte};
     return mp_raw_code_load(&reader);
 }

 // here we define mp_raw_code_load_file depending on the port
 // TODO abstract this away properly

 #if defined(__i386__) || defined(__x86_64__) || (defined(__arm__) && (defined(__unix__)))
 // unix file reader

 #include <sys/stat.h>
 #include <fcntl.h>
 #include <unistd.h>

 typedef struct _mp_lexer_file_buf_t {
     int fd;
     byte buf[20];
     mp_uint_t len;
     mp_uint_t pos;
 } mp_lexer_file_buf_t;

 STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
     mp_lexer_file_buf_t *fb = fb_in;
     if (fb->pos >= fb->len) {
         if (fb->len == 0) {
             return (mp_uint_t)-1;
         } else {
             int n = read(fb->fd, fb->buf, sizeof(fb->buf));
             if (n <= 0) {
                 fb->len = 0;
                 return (mp_uint_t)-1;
             }
             fb->len = n;
             fb->pos = 0;
         }
     }
     return fb->buf[fb->pos++];
 }

 mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
     mp_lexer_file_buf_t fb;
     fb.fd = open(filename, O_RDONLY, 0644);
     int n = read(fb.fd, fb.buf, sizeof(fb.buf));
     fb.len = n;
     fb.pos = 0;
     mp_reader_t reader;
     reader.data = &fb;
     reader.read_byte = file_buf_next_byte;
     mp_raw_code_t *rc = mp_raw_code_load(&reader);
     close(fb.fd);
     return rc;
 }

 #elif defined(__thumb2__)
 // fatfs file reader (assume thumb2 arch uses fatfs...)

 #include "lib/fatfs/ff.h"

 typedef struct _mp_lexer_file_buf_t {
     FIL fp;
     byte buf[20];
     uint16_t len;
     uint16_t pos;
 } mp_lexer_file_buf_t;

 STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
     mp_lexer_file_buf_t *fb = fb_in;
     if (fb->pos >= fb->len) {
         if (fb->len < sizeof(fb->buf)) {
             return (mp_uint_t)-1;
         } else {
             UINT n;
             f_read(&fb->fp, fb->buf, sizeof(fb->buf), &n);
             if (n == 0) {
                 return (mp_uint_t)-1;
             }
             fb->len = n;
             fb->pos = 0;
         }
     }
     return fb->buf[fb->pos++];
 }

 mp_raw_code_t *mp_raw_code_load_file(const char *filename) {
     mp_lexer_file_buf_t fb;
     /*FRESULT res =*/ f_open(&fb.fp, filename, FA_READ);
     UINT n;
     f_read(&fb.fp, fb.buf, sizeof(fb.buf), &n);
     fb.len = n;
     fb.pos = 0;

     mp_reader_t reader;
     reader.data = &fb;
     reader.read_byte = file_buf_next_byte;
     mp_raw_code_t *rc = mp_raw_code_load(&reader);

     f_close(&fb.fp);

     return rc;
 }

 #endif

 #endif // MICROPY_PERSISTENT_CODE_LOAD

 #if MICROPY_PERSISTENT_CODE_SAVE

 #include "py/objstr.h"

 STATIC void mp_print_bytes(mp_print_t *print, const byte *data, size_t len) {
     print->print_strn(print->data, (const char*)data, len);
 }

 #define BYTES_FOR_INT ((BYTES_PER_WORD * 8 + 6) / 7)
 STATIC void mp_print_uint(mp_print_t *print, mp_uint_t n) {
     byte buf[BYTES_FOR_INT];
     byte *p = buf + sizeof(buf);
     *--p = n & 0x7f;
     n >>= 7;
     for (; n != 0; n >>= 7) {
         *--p = 0x80 | (n & 0x7f);
     }
     print->print_strn(print->data, (char*)p, buf + sizeof(buf) - p);
 }

 STATIC void save_qstr(mp_print_t *print, qstr qst) {
     size_t len;
     const byte *str = qstr_data(qst, &len);
     mp_print_uint(print, len);
     mp_print_bytes(print, str, len);
 }

 STATIC void save_obj(mp_print_t *print, mp_obj_t o) {
     if (MP_OBJ_IS_STR_OR_BYTES(o)) {
         byte obj_type;
         if (MP_OBJ_IS_STR(o)) {
             obj_type = 's';
         } else {
             obj_type = 'b';
         }
         mp_uint_t len;
         const char *str = mp_obj_str_get_data(o, &len);
         mp_print_bytes(print, &obj_type, 1);
         mp_print_uint(print, len);
         mp_print_bytes(print, (const byte*)str, len);
     } else if (MP_OBJ_TO_PTR(o) == &mp_const_ellipsis_obj) {
         byte obj_type = 'e';
         mp_print_bytes(print, &obj_type, 1);
     } else {
         // we save numbers using a simplistic text representation
         // TODO could be improved
         byte obj_type;
         if (MP_OBJ_IS_TYPE(o, &mp_type_int)) {
             obj_type = 'i';
         } else if (mp_obj_is_float(o)) {
             obj_type = 'f';
         } else {
             assert(MP_OBJ_IS_TYPE(o, &mp_type_complex));
             obj_type = 'c';
         }
         vstr_t vstr;
         mp_print_t pr;
         vstr_init_print(&vstr, 10, &pr);
         mp_obj_print_helper(&pr, o, PRINT_REPR);
         mp_print_bytes(print, &obj_type, 1);
         mp_print_uint(print, vstr.len);
         mp_print_bytes(print, (const byte*)vstr.buf, vstr.len);
         vstr_clear(&vstr);
     }
 }

 STATIC void save_bytecode_qstrs(mp_print_t *print, const byte *ip, const byte *ip_top) {
     while (ip < ip_top) {
         size_t sz;
         uint f = mp_opcode_format(ip, &sz);
         if (f == MP_OPCODE_QSTR) {
             qstr qst = ip[1] | (ip[2] << 8);
             save_qstr(print, qst);
         }
         ip += sz;
     }
 }

 STATIC void save_raw_code(mp_print_t *print, mp_raw_code_t *rc) {
     if (rc->kind != MP_CODE_BYTECODE) {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
             "can only save bytecode"));
     }

     // save bytecode
     mp_print_uint(print, rc->data.u_byte.bc_len);
     mp_print_bytes(print, rc->data.u_byte.bytecode, rc->data.u_byte.bc_len);

     // extract prelude
     const byte *ip = rc->data.u_byte.bytecode;
     const byte *ip2;
     bytecode_prelude_t prelude;
     extract_prelude(&ip, &ip2, &prelude);

     // save qstrs
     save_qstr(print, ip2[0] | (ip2[1] << 8)); // simple_name
     save_qstr(print, ip2[2] | (ip2[3] << 8)); // source_file
     save_bytecode_qstrs(print, ip, rc->data.u_byte.bytecode + rc->data.u_byte.bc_len);

     // save constant table
     mp_print_uint(print, rc->data.u_byte.n_obj);
     mp_print_uint(print, rc->data.u_byte.n_raw_code);
     const mp_uint_t *const_table = rc->data.u_byte.const_table;
     for (uint i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
         mp_obj_t o = (mp_obj_t)*const_table++;
         save_qstr(print, MP_OBJ_QSTR_VALUE(o));
     }
     for (uint i = 0; i < rc->data.u_byte.n_obj; ++i) {
         save_obj(print, (mp_obj_t)*const_table++);
     }
     for (uint i = 0; i < rc->data.u_byte.n_raw_code; ++i) {
         save_raw_code(print, (mp_raw_code_t*)(uintptr_t)*const_table++);
     }
 }

 void mp_raw_code_save(mp_raw_code_t *rc, mp_print_t *print) {
     // header contains:
     //  byte  'M'
     //  byte  version
     //  byte  feature flags
     //  byte  number of bits in a small int
     byte header[4] = {'M', 0, MPY_FEATURE_FLAGS_DYNAMIC,
         #if MICROPY_DYNAMIC_COMPILER
         mp_dynamic_compiler.small_int_bits,
         #else
         mp_small_int_bits(),
         #endif
     };
     mp_print_bytes(print, header, sizeof(header));

     save_raw_code(print, rc);
 }

 // here we define mp_raw_code_save_file depending on the port
 // TODO abstract this away properly

 #if defined(__i386__) || defined(__x86_64__) || (defined(__arm__) && (defined(__unix__)))

 #include <unistd.h>
 #include <sys/stat.h>
 #include <fcntl.h>

 STATIC void fd_print_strn(void *env, const char *str, size_t len) {
     int fd = (intptr_t)env;
     ssize_t ret = write(fd, str, len);
     (void)ret;
 }

 void mp_raw_code_save_file(mp_raw_code_t *rc, const char *filename) {
     int fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0644);
     mp_print_t fd_print = {(void*)(intptr_t)fd, fd_print_strn};
     mp_raw_code_save(rc, &fd_print);
     close(fd);
 }

 #else
 #error mp_raw_code_save_file not implemented for this platform
 #endif

 #endif // MICROPY_PERSISTENT_CODE_SAVE
	/*
	* This file is part of the Micro Python project, http://micropython.org/
	*
	* The MIT License (MIT)
	*
	* Copyright (c) 2013, 2014 Damien P. George
	*
	* Permission is hereby granted, free of charge, to any person obtaining a copy
	* of this software and associated documentation files (the "Software"), to deal
	* in the Software without restriction, including without limitation the rights
	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	* copies of the Software, and to permit persons to whom the Software is
	* furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
	* THE SOFTWARE.
	*/

	// This code glues the code emitters to the runtime.

	#include <stdint.h>
	#include <stdio.h>
	#include <string.h>
	#include <assert.h>

	#include "py/emitglue.h"
	#include "py/runtime0.h"
	#include "py/bc.h"

	#if 0 // print debugging info
	#define DEBUG_PRINT (1)
	#define WRITE_CODE (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

	#if MICROPY_DEBUG_PRINTERS
	mp_uint_t mp_verbose_flag = 0;
	#endif

	struct _mp_raw_code_t {
	mp_raw_code_kind_t kind : 3;
	mp_uint_t scope_flags : 7;
	mp_uint_t n_pos_args : 11;
	union {
	struct {
	const byte *bytecode;
	const mp_uint_t *const_table;
	#if MICROPY_PERSISTENT_CODE_SAVE
	mp_uint_t bc_len;
	uint16_t n_obj;
	uint16_t n_raw_code;
	#endif
	} u_byte;
	struct {
	void *fun_data;
	const mp_uint_t *const_table;
	mp_uint_t type_sig; // for viper, compressed as 2-bit types; ret is MSB, then arg0, arg1, etc
	} u_native;
	} data;
	};

	mp_raw_code_t *mp_emit_glue_new_raw_code(void) {
	mp_raw_code_t *rc = m_new0(mp_raw_code_t, 1);
	rc->kind = MP_CODE_RESERVED;
	return rc;
	}

	void mp_emit_glue_assign_bytecode(mp_raw_code_t rc, const byte code, mp_uint_t len,
	const mp_uint_t *const_table,
	#if MICROPY_PERSISTENT_CODE_SAVE
	uint16_t n_obj, uint16_t n_raw_code,
	#endif
	mp_uint_t scope_flags) {

	rc->kind = MP_CODE_BYTECODE;
	rc->scope_flags = scope_flags;
	rc->data.u_byte.bytecode = code;
	rc->data.u_byte.const_table = const_table;
	#if MICROPY_PERSISTENT_CODE_SAVE
	rc->data.u_byte.bc_len = len;
	rc->data.u_byte.n_obj = n_obj;
	rc->data.u_byte.n_raw_code = n_raw_code;
	#endif

	#ifdef DEBUG_PRINT
	DEBUG_printf("assign byte code: code=%p len=" UINT_FMT " flags=%x\n", code, len, (uint)scope_flags);
	#endif
	#if MICROPY_DEBUG_PRINTERS
	if (mp_verbose_flag >= 2) {
	mp_bytecode_print(rc, code, len, const_table);
	}
	#endif
	}

	#if MICROPY_EMIT_NATIVE \|\| MICROPY_EMIT_INLINE_THUMB
	void mp_emit_glue_assign_native(mp_raw_code_t rc, mp_raw_code_kind_t kind, void fun_data, mp_uint_t fun_len, const mp_uint_t *const_table, mp_uint_t n_pos_args, mp_uint_t scope_flags, mp_uint_t type_sig) {
	assert(kind == MP_CODE_NATIVE_PY \|\| kind == MP_CODE_NATIVE_VIPER \|\| kind == MP_CODE_NATIVE_ASM);
	rc->kind = kind;
	rc->scope_flags = scope_flags;
	rc->n_pos_args = n_pos_args;
	rc->data.u_native.fun_data = fun_data;
	rc->data.u_native.const_table = const_table;
	rc->data.u_native.type_sig = type_sig;

	#ifdef DEBUG_PRINT
	DEBUG_printf("assign native: kind=%d fun=%p len=" UINT_FMT " n_pos_args=" UINT_FMT " flags=%x\n", kind, fun_data, fun_len, n_pos_args, (uint)scope_flags);
	for (mp_uint_t i = 0; i < fun_len; i++) {
	if (i > 0 && i % 16 == 0) {
	DEBUG_printf("\n");
	}
	DEBUG_printf(" %02x", ((byte*)fun_data)[i]);
	}
	DEBUG_printf("\n");

	#ifdef WRITE_CODE
	FILE *fp_write_code = fopen("out-code", "wb");
	fwrite(fun_data, fun_len, 1, fp_write_code);
	fclose(fp_write_code);
	#endif
	#else
	(void)fun_len;
	#endif
	}
	#endif

	mp_obj_t mp_make_function_from_raw_code(mp_raw_code_t *rc, mp_obj_t def_args, mp_obj_t def_kw_args) {
	DEBUG_OP_printf("make_function_from_raw_code %p\n", rc);
	assert(rc != NULL);

	// def_args must be MP_OBJ_NULL or a tuple
	assert(def_args == MP_OBJ_NULL \|\| MP_OBJ_IS_TYPE(def_args, &mp_type_tuple));

	// def_kw_args must be MP_OBJ_NULL or a dict
	assert(def_kw_args == MP_OBJ_NULL \|\| MP_OBJ_IS_TYPE(def_kw_args, &mp_type_dict));

	// make the function, depending on the raw code kind
	mp_obj_t fun;
	switch (rc->kind) {
	case MP_CODE_BYTECODE:
	no_other_choice:
	fun = mp_obj_new_fun_bc(def_args, def_kw_args, rc->data.u_byte.bytecode, rc->data.u_byte.const_table);
	break;
	#if MICROPY_EMIT_NATIVE
	case MP_CODE_NATIVE_PY:
	fun = mp_obj_new_fun_native(def_args, def_kw_args, rc->data.u_native.fun_data, rc->data.u_native.const_table);
	break;
	case MP_CODE_NATIVE_VIPER:
	fun = mp_obj_new_fun_viper(rc->n_pos_args, rc->data.u_native.fun_data, rc->data.u_native.type_sig);
	break;
	#endif
	#if MICROPY_EMIT_INLINE_THUMB
	case MP_CODE_NATIVE_ASM:
	fun = mp_obj_new_fun_asm(rc->n_pos_args, rc->data.u_native.fun_data, rc->data.u_native.type_sig);
	break;
	#endif
	default:
	// raw code was never set (this should not happen)
	assert(0);
	goto no_other_choice; // to help flow control analysis
	}

	// check for generator functions and if so wrap in generator object
	if ((rc->scope_flags & MP_SCOPE_FLAG_GENERATOR) != 0) {
	fun = mp_obj_new_gen_wrap(fun);
	}

	return fun;
	}

	mp_obj_t mp_make_closure_from_raw_code(mp_raw_code_t rc, mp_uint_t n_closed_over, const mp_obj_t args) {
	DEBUG_OP_printf("make_closure_from_raw_code %p " UINT_FMT " %p\n", rc, n_closed_over, args);
	// make function object
	mp_obj_t ffun;
	if (n_closed_over & 0x100) {
	// default positional and keyword args given
	ffun = mp_make_function_from_raw_code(rc, args[0], args[1]);
	} else {
	// default positional and keyword args not given
	ffun = mp_make_function_from_raw_code(rc, MP_OBJ_NULL, MP_OBJ_NULL);
	}
	// wrap function in closure object
	return mp_obj_new_closure(ffun, n_closed_over & 0xff, args + ((n_closed_over >> 7) & 2));
	}

	#if MICROPY_PERSISTENT_CODE

	#include "py/smallint.h"

	// The feature flags byte encodes the compile-time config options that
	// affect the generate bytecode.
	#define MPY_FEATURE_FLAGS ( \
	((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE) << 0) \
	\| ((MICROPY_PY_BUILTINS_STR_UNICODE) << 1) \
	)
	// This is a version of the flags that can be configured at runtime.
	#define MPY_FEATURE_FLAGS_DYNAMIC ( \
	((MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE_DYNAMIC) << 0) \
	\| ((MICROPY_PY_BUILTINS_STR_UNICODE_DYNAMIC) << 1) \
	)

	#if MICROPY_PERSISTENT_CODE_LOAD \|\| (MICROPY_PERSISTENT_CODE_SAVE && !MICROPY_DYNAMIC_COMPILER)
	// The bytecode will depend on the number of bits in a small-int, and
	// this function computes that (could make it a fixed constant, but it
	// would need to be defined in mpconfigport.h).
	STATIC int mp_small_int_bits(void) {
	mp_int_t i = MP_SMALL_INT_MAX;
	int n = 1;
	while (i != 0) {
	i >>= 1;
	++n;
	}
	return n;
	}
	#endif

	typedef struct _bytecode_prelude_t {
	uint n_state;
	uint n_exc_stack;
	uint scope_flags;
	uint n_pos_args;
	uint n_kwonly_args;
	uint n_def_pos_args;
	uint code_info_size;
	} bytecode_prelude_t;

	// ip will point to start of opcodes
	// ip2 will point to simple_name, source_file qstrs
	STATIC void extract_prelude(const byte ip, const byte ip2, bytecode_prelude_t *prelude) {
	prelude->n_state = mp_decode_uint(ip);
	prelude->n_exc_stack = mp_decode_uint(ip);
	prelude->scope_flags = (ip)++;
	prelude->n_pos_args = (ip)++;
	prelude->n_kwonly_args = (ip)++;
	prelude->n_def_pos_args = (ip)++;
	ip2 = ip;
	prelude->code_info_size = mp_decode_uint(ip2);
	*ip += prelude->code_info_size;
	while ((ip)++ != 255) {
	}
	}

	#endif // MICROPY_PERSISTENT_CODE

	#if MICROPY_PERSISTENT_CODE_LOAD

	#include "py/parsenum.h"
	#include "py/bc0.h"

	STATIC int read_byte(mp_reader_t *reader) {
	return reader->read_byte(reader->data);
	}

	STATIC void read_bytes(mp_reader_t reader, byte buf, size_t len) {
	while (len-- > 0) {
	*buf++ = reader->read_byte(reader->data);
	}
	}

	STATIC mp_uint_t read_uint(mp_reader_t *reader) {
	mp_uint_t unum = 0;
	for (;;) {
	byte b = reader->read_byte(reader->data);
	unum = (unum << 7) \| (b & 0x7f);
	if ((b & 0x80) == 0) {
	break;
	}
	}
	return unum;
	}

	STATIC qstr load_qstr(mp_reader_t *reader) {
	mp_uint_t len = read_uint(reader);
	char *str = m_new(char, len);
	read_bytes(reader, (byte*)str, len);
	qstr qst = qstr_from_strn(str, len);
	m_del(char, str, len);
	return qst;
	}

	STATIC mp_obj_t load_obj(mp_reader_t *reader) {
	byte obj_type = read_byte(reader);
	if (obj_type == 'e') {
	return MP_OBJ_FROM_PTR(&mp_const_ellipsis_obj);
	} else {
	size_t len = read_uint(reader);
	vstr_t vstr;
	vstr_init_len(&vstr, len);
	read_bytes(reader, (byte*)vstr.buf, len);
	if (obj_type == 's' \|\| obj_type == 'b') {
	return mp_obj_new_str_from_vstr(obj_type == 's' ? &mp_type_str : &mp_type_bytes, &vstr);
	} else if (obj_type == 'i') {
	return mp_parse_num_integer(vstr.buf, vstr.len, 10, NULL);
	} else {
	assert(obj_type == 'f' \|\| obj_type == 'c');
	return mp_parse_num_decimal(vstr.buf, vstr.len, obj_type == 'c', false, NULL);
	}
	}
	}

	STATIC void load_bytecode_qstrs(mp_reader_t reader, byte ip, byte *ip_top) {
	while (ip < ip_top) {
	size_t sz;
	uint f = mp_opcode_format(ip, &sz);
	if (f == MP_OPCODE_QSTR) {
	qstr qst = load_qstr(reader);
	ip[1] = qst;
	ip[2] = qst >> 8;
	}
	ip += sz;
	}
	}

	STATIC mp_raw_code_t load_raw_code(mp_reader_t reader) {
	// load bytecode
	mp_uint_t bc_len = read_uint(reader);
	byte *bytecode = m_new(byte, bc_len);
	read_bytes(reader, bytecode, bc_len);

	// extract prelude
	const byte *ip = bytecode;
	const byte *ip2;
	bytecode_prelude_t prelude;
	extract_prelude(&ip, &ip2, &prelude);

	// load qstrs and link global qstr ids into bytecode
	qstr simple_name = load_qstr(reader);
	qstr source_file = load_qstr(reader);
	((byte)ip2)[0] = simple_name; ((byte)ip2)[1] = simple_name >> 8;
	((byte)ip2)[2] = source_file; ((byte)ip2)[3] = source_file >> 8;
	load_bytecode_qstrs(reader, (byte*)ip, bytecode + bc_len);

	// load constant table
	mp_uint_t n_obj = read_uint(reader);
	mp_uint_t n_raw_code = read_uint(reader);
	mp_uint_t *const_table = m_new(mp_uint_t, prelude.n_pos_args + prelude.n_kwonly_args + n_obj + n_raw_code);
	mp_uint_t *ct = const_table;
	for (mp_uint_t i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
	*ct++ = (mp_uint_t)MP_OBJ_NEW_QSTR(load_qstr(reader));
	}
	for (mp_uint_t i = 0; i < n_obj; ++i) {
	*ct++ = (mp_uint_t)load_obj(reader);
	}
	for (mp_uint_t i = 0; i < n_raw_code; ++i) {
	*ct++ = (mp_uint_t)(uintptr_t)load_raw_code(reader);
	}

	// create raw_code and return it
	mp_raw_code_t *rc = mp_emit_glue_new_raw_code();
	mp_emit_glue_assign_bytecode(rc, bytecode, bc_len, const_table,
	#if MICROPY_PERSISTENT_CODE_SAVE
	n_obj, n_raw_code,
	#endif
	prelude.scope_flags);
	return rc;
	}

	mp_raw_code_t mp_raw_code_load(mp_reader_t reader) {
	byte header[4];
	read_bytes(reader, header, sizeof(header));
	if (strncmp((char*)header, "M\x00", 2) != 0) {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
	"invalid .mpy file"));
	}
	if (header[2] != MPY_FEATURE_FLAGS \|\| header[3] > mp_small_int_bits()) {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
	"incompatible .mpy file"));
	}
	return load_raw_code(reader);
	}

	typedef struct _mp_mem_reader_t {
	const byte *cur;
	const byte *end;
	} mp_mem_reader_t;

	STATIC mp_uint_t mp_mem_reader_next_byte(void *br_in) {
	mp_mem_reader_t *br = br_in;
	if (br->cur < br->end) {
	return *br->cur++;
	} else {
	return (mp_uint_t)-1;
	}
	}

	mp_raw_code_t mp_raw_code_load_mem(const byte buf, size_t len) {
	mp_mem_reader_t mr = {buf, buf + len};
	mp_reader_t reader = {&mr, mp_mem_reader_next_byte};
	return mp_raw_code_load(&reader);
	}

	// here we define mp_raw_code_load_file depending on the port
	// TODO abstract this away properly

	#if defined(__i386__) \|\| defined(__x86_64__) \|\| (defined(__arm__) && (defined(__unix__)))
	// unix file reader

	#include <sys/stat.h>
	#include <fcntl.h>
	#include <unistd.h>

	typedef struct _mp_lexer_file_buf_t {
	int fd;
	byte buf[20];
	mp_uint_t len;
	mp_uint_t pos;
	} mp_lexer_file_buf_t;

	STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
	mp_lexer_file_buf_t *fb = fb_in;
	if (fb->pos >= fb->len) {
	if (fb->len == 0) {
	return (mp_uint_t)-1;
	} else {
	int n = read(fb->fd, fb->buf, sizeof(fb->buf));
	if (n <= 0) {
	fb->len = 0;
	return (mp_uint_t)-1;
	}
	fb->len = n;
	fb->pos = 0;
	}
	}
	return fb->buf[fb->pos++];
	}

	mp_raw_code_t mp_raw_code_load_file(const char filename) {
	mp_lexer_file_buf_t fb;
	fb.fd = open(filename, O_RDONLY, 0644);
	int n = read(fb.fd, fb.buf, sizeof(fb.buf));
	fb.len = n;
	fb.pos = 0;
	mp_reader_t reader;
	reader.data = &fb;
	reader.read_byte = file_buf_next_byte;
	mp_raw_code_t *rc = mp_raw_code_load(&reader);
	close(fb.fd);
	return rc;
	}

	#elif defined(__thumb2__)
	// fatfs file reader (assume thumb2 arch uses fatfs...)

	#include "lib/fatfs/ff.h"

	typedef struct _mp_lexer_file_buf_t {
	FIL fp;
	byte buf[20];
	uint16_t len;
	uint16_t pos;
	} mp_lexer_file_buf_t;

	STATIC mp_uint_t file_buf_next_byte(void *fb_in) {
	mp_lexer_file_buf_t *fb = fb_in;
	if (fb->pos >= fb->len) {
	if (fb->len < sizeof(fb->buf)) {
	return (mp_uint_t)-1;
	} else {
	UINT n;
	f_read(&fb->fp, fb->buf, sizeof(fb->buf), &n);
	if (n == 0) {
	return (mp_uint_t)-1;
	}
	fb->len = n;
	fb->pos = 0;
	}
	}
	return fb->buf[fb->pos++];
	}

	mp_raw_code_t mp_raw_code_load_file(const char filename) {
	mp_lexer_file_buf_t fb;
	/FRESULT res =/ f_open(&fb.fp, filename, FA_READ);
	UINT n;
	f_read(&fb.fp, fb.buf, sizeof(fb.buf), &n);
	fb.len = n;
	fb.pos = 0;

	mp_reader_t reader;
	reader.data = &fb;
	reader.read_byte = file_buf_next_byte;
	mp_raw_code_t *rc = mp_raw_code_load(&reader);

	f_close(&fb.fp);

	return rc;
	}

	#endif

	#endif // MICROPY_PERSISTENT_CODE_LOAD

	#if MICROPY_PERSISTENT_CODE_SAVE

	#include "py/objstr.h"

	STATIC void mp_print_bytes(mp_print_t print, const byte data, size_t len) {
	print->print_strn(print->data, (const char*)data, len);
	}

	#define BYTES_FOR_INT ((BYTES_PER_WORD * 8 + 6) / 7)
	STATIC void mp_print_uint(mp_print_t *print, mp_uint_t n) {
	byte buf[BYTES_FOR_INT];
	byte *p = buf + sizeof(buf);
	*--p = n & 0x7f;
	n >>= 7;
	for (; n != 0; n >>= 7) {
	*--p = 0x80 \| (n & 0x7f);
	}
	print->print_strn(print->data, (char*)p, buf + sizeof(buf) - p);
	}

	STATIC void save_qstr(mp_print_t *print, qstr qst) {
	size_t len;
	const byte *str = qstr_data(qst, &len);
	mp_print_uint(print, len);
	mp_print_bytes(print, str, len);
	}

	STATIC void save_obj(mp_print_t *print, mp_obj_t o) {
	if (MP_OBJ_IS_STR_OR_BYTES(o)) {
	byte obj_type;
	if (MP_OBJ_IS_STR(o)) {
	obj_type = 's';
	} else {
	obj_type = 'b';
	}
	mp_uint_t len;
	const char *str = mp_obj_str_get_data(o, &len);
	mp_print_bytes(print, &obj_type, 1);
	mp_print_uint(print, len);
	mp_print_bytes(print, (const byte*)str, len);
	} else if (MP_OBJ_TO_PTR(o) == &mp_const_ellipsis_obj) {
	byte obj_type = 'e';
	mp_print_bytes(print, &obj_type, 1);
	} else {
	// we save numbers using a simplistic text representation
	// TODO could be improved
	byte obj_type;
	if (MP_OBJ_IS_TYPE(o, &mp_type_int)) {
	obj_type = 'i';
	} else if (mp_obj_is_float(o)) {
	obj_type = 'f';
	} else {
	assert(MP_OBJ_IS_TYPE(o, &mp_type_complex));
	obj_type = 'c';
	}
	vstr_t vstr;
	mp_print_t pr;
	vstr_init_print(&vstr, 10, &pr);
	mp_obj_print_helper(&pr, o, PRINT_REPR);
	mp_print_bytes(print, &obj_type, 1);
	mp_print_uint(print, vstr.len);
	mp_print_bytes(print, (const byte*)vstr.buf, vstr.len);
	vstr_clear(&vstr);
	}
	}

	STATIC void save_bytecode_qstrs(mp_print_t print, const byte ip, const byte *ip_top) {
	while (ip < ip_top) {
	size_t sz;
	uint f = mp_opcode_format(ip, &sz);
	if (f == MP_OPCODE_QSTR) {
	qstr qst = ip[1] \| (ip[2] << 8);
	save_qstr(print, qst);
	}
	ip += sz;
	}
	}

	STATIC void save_raw_code(mp_print_t print, mp_raw_code_t rc) {
	if (rc->kind != MP_CODE_BYTECODE) {
	nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
	"can only save bytecode"));
	}

	// save bytecode
	mp_print_uint(print, rc->data.u_byte.bc_len);
	mp_print_bytes(print, rc->data.u_byte.bytecode, rc->data.u_byte.bc_len);

	// extract prelude
	const byte *ip = rc->data.u_byte.bytecode;
	const byte *ip2;
	bytecode_prelude_t prelude;
	extract_prelude(&ip, &ip2, &prelude);

	// save qstrs
	save_qstr(print, ip2[0] \| (ip2[1] << 8)); // simple_name
	save_qstr(print, ip2[2] \| (ip2[3] << 8)); // source_file
	save_bytecode_qstrs(print, ip, rc->data.u_byte.bytecode + rc->data.u_byte.bc_len);

	// save constant table
	mp_print_uint(print, rc->data.u_byte.n_obj);
	mp_print_uint(print, rc->data.u_byte.n_raw_code);
	const mp_uint_t *const_table = rc->data.u_byte.const_table;
	for (uint i = 0; i < prelude.n_pos_args + prelude.n_kwonly_args; ++i) {
	mp_obj_t o = (mp_obj_t)*const_table++;
	save_qstr(print, MP_OBJ_QSTR_VALUE(o));
	}
	for (uint i = 0; i < rc->data.u_byte.n_obj; ++i) {
	save_obj(print, (mp_obj_t)*const_table++);
	}
	for (uint i = 0; i < rc->data.u_byte.n_raw_code; ++i) {
	save_raw_code(print, (mp_raw_code_t)(uintptr_t)const_table++);
	}
	}

	void mp_raw_code_save(mp_raw_code_t rc, mp_print_t print) {
	// header contains:
	// byte 'M'
	// byte version
	// byte feature flags
	// byte number of bits in a small int
	byte header[4] = {'M', 0, MPY_FEATURE_FLAGS_DYNAMIC,
	#if MICROPY_DYNAMIC_COMPILER
	mp_dynamic_compiler.small_int_bits,
	#else
	mp_small_int_bits(),
	#endif
	};
	mp_print_bytes(print, header, sizeof(header));

	save_raw_code(print, rc);
	}

	// here we define mp_raw_code_save_file depending on the port
	// TODO abstract this away properly

	#if defined(__i386__) \|\| defined(__x86_64__) \|\| (defined(__arm__) && (defined(__unix__)))

	#include <unistd.h>
	#include <sys/stat.h>
	#include <fcntl.h>

	STATIC void fd_print_strn(void env, const char str, size_t len) {
	int fd = (intptr_t)env;
	ssize_t ret = write(fd, str, len);
	(void)ret;
	}

	void mp_raw_code_save_file(mp_raw_code_t rc, const char filename) {
	int fd = open(filename, O_WRONLY \| O_CREAT \| O_TRUNC, 0644);
	mp_print_t fd_print = {(void*)(intptr_t)fd, fd_print_strn};
	mp_raw_code_save(rc, &fd_print);
	close(fd);
	}

	#else
	#error mp_raw_code_save_file not implemented for this platform
	#endif

	#endif // MICROPY_PERSISTENT_CODE_SAVE