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+/* This example demonstrates the following features in a native module:
+ - defining simple functions exposed to Python
+ - defining local, helper C functions
+ - defining constant integers and strings exposed to Python
+ - getting and creating integer objects
+ - creating Python lists
+ - raising exceptions
+ - allocating memory
+ - BSS and constant data (rodata)
+ - relocated pointers in rodata
+*/
+
+// Include the header file to get access to the MicroPython API
+#include "py/dynruntime.h"
+
+// BSS (zero) data
+uint16_t data16[4];
+
+// Constant data (rodata)
+const uint8_t table8[] = { 0, 1, 1, 2, 3, 5, 8, 13 };
+const uint16_t table16[] = { 0x1000, 0x2000 };
+
+// Constant data pointing to BSS/constant data
+uint16_t *const table_ptr16a[] = { &data16[0], &data16[1], &data16[2], &data16[3] };
+const uint16_t *const table_ptr16b[] = { &table16[0], &table16[1] };
+
+// A simple function that adds its 2 arguments (must be integers)
+STATIC mp_obj_t add(mp_obj_t x_in, mp_obj_t y_in) {
+ mp_int_t x = mp_obj_get_int(x_in);
+ mp_int_t y = mp_obj_get_int(y_in);
+ return mp_obj_new_int(x + y);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(add_obj, add);
+
+// A local helper function (not exposed to Python)
+STATIC mp_int_t fibonacci_helper(mp_int_t x) {
+ if (x < MP_ARRAY_SIZE(table8)) {
+ return table8[x];
+ } else {
+ return fibonacci_helper(x - 1) + fibonacci_helper(x - 2);
+ }
+}
+
+// A function which computes Fibonacci numbers
+STATIC mp_obj_t fibonacci(mp_obj_t x_in) {
+ mp_int_t x = mp_obj_get_int(x_in);
+ if (x < 0) {
+ mp_raise_ValueError("can't compute negative Fibonacci number");
+ }
+ return mp_obj_new_int(fibonacci_helper(x));
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(fibonacci_obj, fibonacci);
+
+// A function that accesses the BSS data
+STATIC mp_obj_t access(size_t n_args, const mp_obj_t *args) {
+ if (n_args == 0) {
+ // Create a list holding all items from data16
+ mp_obj_list_t *lst = MP_OBJ_TO_PTR(mp_obj_new_list(MP_ARRAY_SIZE(data16), NULL));
+ for (int i = 0; i < MP_ARRAY_SIZE(data16); ++i) {
+ lst->items[i] = mp_obj_new_int(data16[i]);
+ }
+ return MP_OBJ_FROM_PTR(lst);
+ } else if (n_args == 1) {
+ // Get one item from data16
+ mp_int_t idx = mp_obj_get_int(args[0]) & 3;
+ return mp_obj_new_int(data16[idx]);
+ } else {
+ // Set one item in data16 (via table_ptr16a)
+ mp_int_t idx = mp_obj_get_int(args[0]) & 3;
+ *table_ptr16a[idx] = mp_obj_get_int(args[1]);
+ return mp_const_none;
+ }
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(access_obj, 0, 2, access);
+
+// A function that allocates memory and creates a bytearray
+STATIC mp_obj_t make_array(void) {
+ uint16_t *ptr = m_new(uint16_t, MP_ARRAY_SIZE(table_ptr16b));
+ for (int i = 0; i < MP_ARRAY_SIZE(table_ptr16b); ++i) {
+ ptr[i] = *table_ptr16b[i];
+ }
+ return mp_obj_new_bytearray_by_ref(sizeof(uint16_t) * MP_ARRAY_SIZE(table_ptr16b), ptr);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_0(make_array_obj, make_array);
+
+// This is the entry point and is called when the module is imported
+mp_obj_t mpy_init(mp_obj_fun_bc_t *self, size_t n_args, size_t n_kw, mp_obj_t *args) {
+ // This must be first, it sets up the globals dict and other things
+ MP_DYNRUNTIME_INIT_ENTRY
+
+ // Messages can be printed as usualy
+ mp_printf(&mp_plat_print, "initialising module self=%p\n", self);
+
+ // Make the functions available in the module's namespace
+ mp_store_global(MP_QSTR_add, MP_OBJ_FROM_PTR(&add_obj));
+ mp_store_global(MP_QSTR_fibonacci, MP_OBJ_FROM_PTR(&fibonacci_obj));
+ mp_store_global(MP_QSTR_access, MP_OBJ_FROM_PTR(&access_obj));
+ mp_store_global(MP_QSTR_make_array, MP_OBJ_FROM_PTR(&make_array_obj));
+
+ // Add some constants to the module's namespace
+ mp_store_global(MP_QSTR_VAL, MP_OBJ_NEW_SMALL_INT(42));
+ mp_store_global(MP_QSTR_MSG, MP_OBJ_NEW_QSTR(MP_QSTR_HELLO_MICROPYTHON));
+
+ // This must be last, it restores the globals dict
+ MP_DYNRUNTIME_INIT_EXIT
+}