add circuitpython code

1 files changed, 793 insertions, 0 deletions

diff --git a/circuitpython/py/objexcept.c b/circuitpython/py/objexcept.c
new file mode 100644
index 0000000..fc07876
--- /dev/null
+++ b/circuitpython/py/objexcept.c
@@ -0,0 +1,793 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * SPDX-FileCopyrightText: Copyright (c) 2013, 2014 Damien P. George
+ * SPDX-FileCopyrightText: Copyright (c) 2014-2016 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 <string.h>
+#include <stdarg.h>
+#include <assert.h>
+#include <stdio.h>
+
+#include "py/objlist.h"
+#include "py/objnamedtuple.h"
+#include "py/objstr.h"
+#include "py/objtuple.h"
+#include "py/objtype.h"
+#include "py/runtime.h"
+#include "py/gc.h"
+#include "py/mperrno.h"
+
+#include "supervisor/shared/translate.h"
+
+// Number of items per traceback entry (file, line, block)
+#define TRACEBACK_ENTRY_LEN (3)
+
+// Optionally allocated buffer for storing some traceback, the tuple argument,
+// and possible string object and data, for when the heap is locked.
+#if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+
+// When used the layout of the emergency exception buffer is:
+//  - traceback entry (file, line, block)
+//  - traceback entry (file, line, block)
+//  - mp_obj_tuple_t object
+//  - n_args * mp_obj_t for tuple
+//  - mp_obj_str_t object
+//  - string data
+#define EMG_BUF_TRACEBACK_OFFSET    (0)
+#define EMG_BUF_TRACEBACK_SIZE      (2 * TRACEBACK_ENTRY_LEN * sizeof(size_t))
+#define EMG_BUF_TUPLE_OFFSET        (EMG_BUF_TRACEBACK_OFFSET + EMG_BUF_TRACEBACK_SIZE)
+#define EMG_BUF_TUPLE_SIZE(n_args)  (sizeof(mp_obj_tuple_t) + n_args * sizeof(mp_obj_t))
+#define EMG_BUF_STR_OFFSET          (EMG_BUF_TUPLE_OFFSET + EMG_BUF_TUPLE_SIZE(1))
+#define EMG_BUF_STR_BUF_OFFSET      (EMG_BUF_STR_OFFSET + sizeof(mp_obj_str_t))
+
+#if MICROPY_EMERGENCY_EXCEPTION_BUF_SIZE > 0
+#define mp_emergency_exception_buf_size MICROPY_EMERGENCY_EXCEPTION_BUF_SIZE
+
+void mp_init_emergency_exception_buf(void) {
+    // Nothing to do since the buffer was declared statically. We put this
+    // definition here so that the calling code can call this function
+    // regardless of how its configured (makes the calling code a bit cleaner).
+}
+
+#else
+#define mp_emergency_exception_buf_size MP_STATE_VM(mp_emergency_exception_buf_size)
+
+void mp_init_emergency_exception_buf(void) {
+    mp_emergency_exception_buf_size = 0;
+    MP_STATE_VM(mp_emergency_exception_buf) = NULL;
+}
+
+mp_obj_t mp_alloc_emergency_exception_buf(mp_obj_t size_in) {
+    mp_int_t size = mp_obj_get_int(size_in);
+    void *buf = NULL;
+    if (size > 0) {
+        buf = m_new(byte, size);
+    }
+
+    int old_size = mp_emergency_exception_buf_size;
+    void *old_buf = MP_STATE_VM(mp_emergency_exception_buf);
+
+    // Update the 2 variables atomically so that an interrupt can't occur
+    // between the assignments.
+    mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
+    mp_emergency_exception_buf_size = size;
+    MP_STATE_VM(mp_emergency_exception_buf) = buf;
+    MICROPY_END_ATOMIC_SECTION(atomic_state);
+
+    if (old_buf != NULL) {
+        m_del(byte, old_buf, old_size);
+    }
+    return mp_const_none;
+}
+#endif
+#endif  // MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+
+mp_obj_exception_t *mp_obj_exception_get_native(mp_obj_t self_in) {
+    assert(mp_obj_is_exception_instance(self_in));
+    if (mp_obj_is_native_exception_instance(self_in)) {
+        return MP_OBJ_TO_PTR(self_in);
+    } else {
+        return MP_OBJ_TO_PTR(((mp_obj_instance_t *)MP_OBJ_TO_PTR(self_in))->subobj[0]);
+    }
+}
+
+void mp_obj_exception_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t kind) {
+    mp_obj_exception_t *o = MP_OBJ_TO_PTR(o_in);
+    mp_print_kind_t k = kind & ~PRINT_EXC_SUBCLASS;
+    bool is_subclass = kind & PRINT_EXC_SUBCLASS;
+    if (!is_subclass && (k == PRINT_REPR || k == PRINT_EXC)) {
+        mp_print_str(print, qstr_str(o->base.type->name));
+    }
+
+    if (k == PRINT_EXC) {
+        mp_print_str(print, ": ");
+    }
+
+    if (k == PRINT_STR || k == PRINT_EXC) {
+        if (o->args == NULL || o->args->len == 0) {
+            mp_print_str(print, "");
+            return;
+        }
+        #if MICROPY_PY_UERRNO
+        // try to provide a nice OSError error message
+        if (o->base.type == &mp_type_OSError && o->args->len > 0 && o->args->len < 3 && mp_obj_is_small_int(o->args->items[0])) {
+            char decompressed[50];
+            const char *msg = mp_common_errno_to_str(o->args->items[0], decompressed, sizeof(decompressed));
+            if (msg != NULL) {
+                mp_printf(print, "[Errno " INT_FMT "] %s", MP_OBJ_SMALL_INT_VALUE(o->args->items[0]), msg);
+                if (o->args->len > 1) {
+                    mp_print_str(print, ": ");
+                    mp_obj_print_helper(print, o->args->items[1], PRINT_STR);
+                }
+                return;
+            }
+        }
+        #endif
+
+        if (o->args->len == 1) {
+            mp_obj_print_helper(print, o->args->items[0], PRINT_STR);
+            return;
+        }
+    }
+
+    mp_obj_tuple_print(print, MP_OBJ_FROM_PTR(o->args), kind);
+}
+
+mp_obj_t mp_obj_exception_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
+    mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, false);
+
+    // Try to allocate memory for the exception, with fallback to emergency exception object
+    mp_obj_exception_t *o_exc = m_new_obj_maybe(mp_obj_exception_t);
+    if (o_exc == NULL) {
+        o_exc = &MP_STATE_VM(mp_emergency_exception_obj);
+    }
+
+    // Populate the exception object
+    o_exc->base.type = type;
+    o_exc->traceback = (mp_obj_traceback_t *)&mp_const_empty_traceback_obj;
+
+    mp_obj_tuple_t *o_tuple;
+    if (n_args == 0) {
+        // No args, can use the empty tuple straightaway
+        o_tuple = (mp_obj_tuple_t *)&mp_const_empty_tuple_obj;
+    } else {
+        // Try to allocate memory for the tuple containing the args
+        o_tuple = m_new_obj_var_maybe(mp_obj_tuple_t, mp_obj_t, n_args);
+
+        #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+        // If we are called by mp_obj_new_exception_msg_varg then it will have
+        // reserved room (after the traceback data) for a tuple with 1 element.
+        // Otherwise we are free to use the whole buffer after the traceback data.
+        if (o_tuple == NULL && mp_emergency_exception_buf_size >=
+            (mp_int_t)(EMG_BUF_TUPLE_OFFSET + EMG_BUF_TUPLE_SIZE(n_args))) {
+            o_tuple = (mp_obj_tuple_t *)
+                ((uint8_t *)MP_STATE_VM(mp_emergency_exception_buf) + EMG_BUF_TUPLE_OFFSET);
+        }
+        #endif
+
+        if (o_tuple == NULL) {
+            // No memory for a tuple, fallback to an empty tuple
+            o_tuple = (mp_obj_tuple_t *)&mp_const_empty_tuple_obj;
+        } else {
+            // Have memory for a tuple so populate it
+            o_tuple->base.type = &mp_type_tuple;
+            o_tuple->len = n_args;
+            memcpy(o_tuple->items, args, n_args * sizeof(mp_obj_t));
+        }
+    }
+
+    // Store the tuple of args in the exception object
+    o_exc->args = o_tuple;
+
+    return MP_OBJ_FROM_PTR(o_exc);
+}
+
+// Get exception "value" - that is, first argument, or None
+mp_obj_t mp_obj_exception_get_value(mp_obj_t self_in) {
+    mp_obj_exception_t *self = mp_obj_exception_get_native(self_in);
+    if (self->args->len == 0) {
+        return mp_const_none;
+    } else {
+        return self->args->items[0];
+    }
+}
+
+void mp_obj_exception_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
+    mp_obj_exception_t *self = MP_OBJ_TO_PTR(self_in);
+    if (dest[0] != MP_OBJ_NULL) {
+        // store/delete attribute
+        if (attr == MP_QSTR___traceback__) {
+            if (dest[1] == mp_const_none) {
+                self->traceback = (mp_obj_traceback_t *)&mp_const_empty_traceback_obj;
+            } else {
+                if (!mp_obj_is_type(dest[1], &mp_type_traceback)) {
+                    mp_raise_TypeError(MP_ERROR_TEXT("invalid traceback"));
+                }
+                self->traceback = MP_OBJ_TO_PTR(dest[1]);
+            }
+            dest[0] = MP_OBJ_NULL; // indicate success
+        }
+        return;
+    }
+    if (attr == MP_QSTR_args) {
+        dest[0] = MP_OBJ_FROM_PTR(self->args);
+    } else if (attr == MP_QSTR_value && self->base.type == &mp_type_StopIteration) {
+        dest[0] = mp_obj_exception_get_value(self_in);
+    } else if (attr == MP_QSTR___traceback__) {
+        dest[0] = (self->traceback) ? MP_OBJ_FROM_PTR(self->traceback) : mp_const_none;
+    #if MICROPY_CPYTHON_COMPAT
+    } else if (mp_obj_is_subclass_fast(MP_OBJ_FROM_PTR(self->base.type), MP_OBJ_FROM_PTR(&mp_type_OSError))) {
+        if (attr == MP_QSTR_errno) {
+            dest[0] = mp_obj_exception_get_value(self_in);
+        } else if (attr == MP_QSTR_strerror) {
+            if (self->args->len > 1) {
+                dest[0] = self->args->items[1];
+            } else if (self->args->len > 0) {
+                char decompressed[50];
+                const char *msg = mp_common_errno_to_str(self->args->items[0], decompressed, sizeof(decompressed));
+                if (msg != NULL) {
+                    dest[0] = mp_obj_new_str(msg, strlen(msg));
+                } else {
+                    dest[0] = mp_const_none;
+                }
+            } else {
+                dest[0] = mp_const_none;
+            }
+        } else if (attr == MP_QSTR_filename) {
+            dest[0] = self->args->len > 2 ? self->args->items[2] : mp_const_none;
+            // skip winerror
+        } else if (attr == MP_QSTR_filename2) {
+            dest[0] = self->args->len > 4 ? self->args->items[4] : mp_const_none;
+        }
+    #endif
+    }
+}
+
+const mp_obj_type_t mp_type_BaseException = {
+    { &mp_type_type },
+    .name = MP_QSTR_BaseException,
+    .print = mp_obj_exception_print,
+    .make_new = mp_obj_exception_make_new,
+    .attr = mp_obj_exception_attr,
+};
+
+// *FORMAT-OFF*
+
+// List of all exceptions, arranged as in the table at:
+// http://docs.python.org/3/library/exceptions.html
+MP_DEFINE_EXCEPTION(SystemExit, BaseException)
+MP_DEFINE_EXCEPTION(KeyboardInterrupt, BaseException)
+MP_DEFINE_EXCEPTION(ReloadException, BaseException)
+MP_DEFINE_EXCEPTION(GeneratorExit, BaseException)
+MP_DEFINE_EXCEPTION(Exception, BaseException)
+  #if MICROPY_PY_ASYNC_AWAIT
+MP_DEFINE_EXCEPTION(StopAsyncIteration, Exception)
+  #endif
+MP_DEFINE_EXCEPTION(StopIteration, Exception)
+MP_DEFINE_EXCEPTION(ArithmeticError, Exception)
+// MP_DEFINE_EXCEPTION(FloatingPointError, ArithmeticError)
+MP_DEFINE_EXCEPTION(OverflowError, ArithmeticError)
+MP_DEFINE_EXCEPTION(ZeroDivisionError, ArithmeticError)
+MP_DEFINE_EXCEPTION(AssertionError, Exception)
+MP_DEFINE_EXCEPTION(AttributeError, Exception)
+// MP_DEFINE_EXCEPTION(BufferError, Exception)
+// MP_DEFINE_EXCEPTION(EnvironmentError, Exception) use OSError instead
+MP_DEFINE_EXCEPTION(EOFError, Exception)
+MP_DEFINE_EXCEPTION(ImportError, Exception)
+// MP_DEFINE_EXCEPTION(IOError, Exception) use OSError instead
+MP_DEFINE_EXCEPTION(LookupError, Exception)
+MP_DEFINE_EXCEPTION(IndexError, LookupError)
+MP_DEFINE_EXCEPTION(KeyError, LookupError)
+MP_DEFINE_EXCEPTION(MemoryError, Exception)
+MP_DEFINE_EXCEPTION(NameError, Exception)
+/*
+    MP_DEFINE_EXCEPTION(UnboundLocalError, NameError)
+    */
+MP_DEFINE_EXCEPTION(OSError, Exception)
+MP_DEFINE_EXCEPTION(TimeoutError, OSError)
+MP_DEFINE_EXCEPTION(ConnectionError, OSError)
+MP_DEFINE_EXCEPTION(BrokenPipeError, ConnectionError)
+/*
+      MP_DEFINE_EXCEPTION(ConnectionAbortedError, ConnectionError)
+      MP_DEFINE_EXCEPTION(ConnectionRefusedError, ConnectionError)
+      MP_DEFINE_EXCEPTION(ConnectionResetError, ConnectionError)
+      */
+/*
+    MP_DEFINE_EXCEPTION(BlockingIOError, OSError)
+    MP_DEFINE_EXCEPTION(ChildProcessError, OSError)
+    MP_DEFINE_EXCEPTION(InterruptedError, OSError)
+    MP_DEFINE_EXCEPTION(IsADirectoryError, OSError)
+    MP_DEFINE_EXCEPTION(NotADirectoryError, OSError)
+    MP_DEFINE_EXCEPTION(PermissionError, OSError)
+    MP_DEFINE_EXCEPTION(ProcessLookupError, OSError)
+    MP_DEFINE_EXCEPTION(TimeoutError, OSError)
+    MP_DEFINE_EXCEPTION(FileExistsError, OSError)
+    MP_DEFINE_EXCEPTION(FileNotFoundError, OSError)
+    MP_DEFINE_EXCEPTION(ReferenceError, Exception)
+    */
+MP_DEFINE_EXCEPTION(RuntimeError, Exception)
+MP_DEFINE_EXCEPTION(NotImplementedError, RuntimeError)
+MP_DEFINE_EXCEPTION(SyntaxError, Exception)
+MP_DEFINE_EXCEPTION(IndentationError, SyntaxError)
+/*
+      MP_DEFINE_EXCEPTION(TabError, IndentationError)
+      */
+// MP_DEFINE_EXCEPTION(SystemError, Exception)
+MP_DEFINE_EXCEPTION(TypeError, Exception)
+#if MICROPY_EMIT_NATIVE
+MP_DEFINE_EXCEPTION(ViperTypeError, TypeError)
+#endif
+MP_DEFINE_EXCEPTION(ValueError, Exception)
+#if MICROPY_PY_BUILTINS_STR_UNICODE
+MP_DEFINE_EXCEPTION(UnicodeError, ValueError)
+// TODO: Implement more UnicodeError subclasses which take arguments
+#endif
+#if CIRCUITPY_ALARM
+MP_DEFINE_EXCEPTION(DeepSleepRequest, BaseException)
+#endif
+MP_DEFINE_EXCEPTION(MpyError, ValueError)
+/*
+  MP_DEFINE_EXCEPTION(Warning, Exception)
+    MP_DEFINE_EXCEPTION(DeprecationWarning, Warning)
+    MP_DEFINE_EXCEPTION(PendingDeprecationWarning, Warning)
+    MP_DEFINE_EXCEPTION(RuntimeWarning, Warning)
+    MP_DEFINE_EXCEPTION(SyntaxWarning, Warning)
+    MP_DEFINE_EXCEPTION(UserWarning, Warning)
+    MP_DEFINE_EXCEPTION(FutureWarning, Warning)
+    MP_DEFINE_EXCEPTION(ImportWarning, Warning)
+    MP_DEFINE_EXCEPTION(UnicodeWarning, Warning)
+    MP_DEFINE_EXCEPTION(BytesWarning, Warning)
+    MP_DEFINE_EXCEPTION(ResourceWarning, Warning)
+    */
+
+// *FORMAT-ON*
+
+mp_obj_t mp_obj_new_exception(const mp_obj_type_t *exc_type) {
+    assert(exc_type->make_new == mp_obj_exception_make_new);
+    return mp_obj_exception_make_new(exc_type, 0, 0, NULL);
+}
+
+mp_obj_t mp_obj_new_exception_args(const mp_obj_type_t *exc_type, size_t n_args, const mp_obj_t *args) {
+    assert(exc_type->make_new == mp_obj_exception_make_new);
+    return exc_type->make_new(exc_type, n_args, 0, args);
+}
+
+#if MICROPY_ERROR_REPORTING != MICROPY_ERROR_REPORTING_NONE
+mp_obj_t mp_obj_new_exception_msg(const mp_obj_type_t *exc_type, const compressed_string_t *msg) {
+    return mp_obj_new_exception_msg_varg(exc_type, msg);
+}
+#endif
+
+// The following struct and function implement a simple printer that conservatively
+// allocates memory and truncates the output data if no more memory can be obtained.
+// It leaves room for a null byte at the end of the buffer.
+
+struct _exc_printer_t {
+    bool allow_realloc;
+    size_t alloc;
+    size_t len;
+    byte *buf;
+};
+
+STATIC void exc_add_strn(void *data, const char *str, size_t len) {
+    struct _exc_printer_t *pr = data;
+    if (pr->len + len >= pr->alloc) {
+        // Not enough room for data plus a null byte so try to grow the buffer
+        if (pr->allow_realloc) {
+            size_t new_alloc = pr->alloc + len + 16;
+            byte *new_buf = m_renew_maybe(byte, pr->buf, pr->alloc, new_alloc, true);
+            if (new_buf == NULL) {
+                pr->allow_realloc = false;
+                len = pr->alloc - pr->len - 1;
+            } else {
+                pr->alloc = new_alloc;
+                pr->buf = new_buf;
+            }
+        } else {
+            len = pr->alloc - pr->len - 1;
+        }
+    }
+    memcpy(pr->buf + pr->len, str, len);
+    pr->len += len;
+}
+
+
+mp_obj_t mp_obj_new_exception_msg_varg(const mp_obj_type_t *exc_type, const compressed_string_t *fmt, ...) {
+    va_list ap;
+    va_start(ap, fmt);
+    mp_obj_t exception = mp_obj_new_exception_msg_vlist(exc_type, fmt, ap);
+    va_end(ap);
+    return exception;
+}
+
+mp_obj_t mp_obj_new_exception_msg_vlist(const mp_obj_type_t *exc_type, const compressed_string_t *fmt, va_list ap) {
+    assert(fmt != NULL);
+
+    // Check that the given type is an exception type
+    assert(exc_type->make_new == mp_obj_exception_make_new);
+
+    // Try to allocate memory for the message
+    mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
+    size_t o_str_alloc = decompress_length(fmt);
+    byte *o_str_buf = m_new_maybe(byte, o_str_alloc);
+
+    bool used_emg_buf = false;
+    #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+    // If memory allocation failed and there is an emergency buffer then try to use
+    // that buffer to store the string object and its data (at least 16 bytes for
+    // the string data), reserving room at the start for the traceback and 1-tuple.
+    if ((o_str == NULL || o_str_buf == NULL)
+        && mp_emergency_exception_buf_size >= (mp_int_t)(EMG_BUF_STR_OFFSET + sizeof(mp_obj_str_t) + 16)) {
+        used_emg_buf = true;
+        o_str = (mp_obj_str_t *)((uint8_t *)MP_STATE_VM(mp_emergency_exception_buf)
+            + EMG_BUF_STR_OFFSET);
+        o_str_buf = (byte *)&o_str[1];
+        o_str_alloc = (uint8_t *)MP_STATE_VM(mp_emergency_exception_buf)
+            + mp_emergency_exception_buf_size - o_str_buf;
+    }
+    #endif
+
+    if (o_str == NULL) {
+        // No memory for the string object so create the exception with no args.
+        // The exception will only have a type and no message (compression is irrelevant).
+        return mp_obj_exception_make_new(exc_type, 0, 0, NULL);
+    }
+
+    if (o_str_buf == NULL) {
+        // No memory for the string buffer: the string is compressed so don't add it.
+        o_str->len = 0;
+        o_str->data = NULL;
+    } else {
+        // We have some memory to format the string.
+        struct _exc_printer_t exc_pr = {!used_emg_buf, o_str_alloc, 0, o_str_buf};
+        mp_print_t print = {&exc_pr, exc_add_strn};
+        mp_vcprintf(&print, fmt, ap);
+        exc_pr.buf[exc_pr.len] = '\0';
+        o_str->len = exc_pr.len;
+        o_str->data = exc_pr.buf;
+    }
+
+    // Create the string object and call mp_obj_exception_make_new to create the exception
+    o_str->base.type = &mp_type_str;
+    o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
+    mp_obj_t arg = MP_OBJ_FROM_PTR(o_str);
+    return mp_obj_exception_make_new(exc_type, 1, 0, &arg);
+}
+
+mp_obj_t mp_obj_new_exception_msg_str(const mp_obj_type_t *exc_type, const char *msg) {
+    assert(msg != NULL);
+
+    // Check that the given type is an exception type
+    assert(exc_type->make_new == mp_obj_exception_make_new);
+
+    // Try to allocate memory for the message
+    mp_obj_str_t *o_str = m_new_obj_maybe(mp_obj_str_t);
+
+    #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+    // If memory allocation failed and there is an emergency buffer then try to use
+    // that buffer to store the string object and its data (at least 16 bytes for
+    // the string data), reserving room at the start for the traceback and 1-tuple.
+    if (o_str == NULL
+        && mp_emergency_exception_buf_size >= EMG_BUF_STR_OFFSET + sizeof(mp_obj_str_t) + 16) {
+        o_str = (mp_obj_str_t *)((uint8_t *)MP_STATE_VM(mp_emergency_exception_buf)
+            + EMG_BUF_STR_OFFSET);
+    }
+    #endif
+
+    if (o_str == NULL) {
+        // No memory for the string object so create the exception with no args
+        return mp_obj_exception_make_new(exc_type, 0, 0, NULL);
+    }
+
+    // Assume the message is statically allocated.
+    o_str->len = strlen(msg);
+    o_str->data = (const byte *)msg;
+
+    // Create the string object and call mp_obj_exception_make_new to create the exception
+    o_str->base.type = &mp_type_str;
+    o_str->hash = qstr_compute_hash(o_str->data, o_str->len);
+    mp_obj_t arg = MP_OBJ_FROM_PTR(o_str);
+    return mp_obj_exception_make_new(exc_type, 1, 0, &arg);
+}
+
+// return true if the given object is an exception type
+bool mp_obj_is_exception_type(mp_obj_t self_in) {
+    if (mp_obj_is_type(self_in, &mp_type_type)) {
+        // optimisation when self_in is a builtin exception
+        mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in);
+        if (self->make_new == mp_obj_exception_make_new) {
+            return true;
+        }
+    }
+    return mp_obj_is_subclass_fast(self_in, MP_OBJ_FROM_PTR(&mp_type_BaseException));
+}
+
+// return true if the given object is an instance of an exception type
+bool mp_obj_is_exception_instance(mp_obj_t self_in) {
+    return mp_obj_is_exception_type(MP_OBJ_FROM_PTR(mp_obj_get_type(self_in)));
+}
+
+// Return true if exception (type or instance) is a subclass of given
+// exception type.  Assumes exc_type is a subclass of BaseException, as
+// defined by mp_obj_is_exception_type(exc_type).
+bool mp_obj_exception_match(mp_obj_t exc, mp_const_obj_t exc_type) {
+    // if exc is an instance of an exception, then extract and use its type
+    if (mp_obj_is_exception_instance(exc)) {
+        exc = MP_OBJ_FROM_PTR(mp_obj_get_type(exc));
+    }
+    return mp_obj_is_subclass_fast(exc, exc_type);
+}
+
+// traceback handling functions
+
+void mp_obj_exception_clear_traceback(mp_obj_t self_in) {
+    mp_obj_exception_t *self = mp_obj_exception_get_native(self_in);
+    // just set the traceback to the empty traceback object
+    // we don't want to call any memory management functions here
+    self->traceback = (mp_obj_traceback_t *)&mp_const_empty_traceback_obj;
+}
+
+void mp_obj_exception_add_traceback(mp_obj_t self_in, qstr file, size_t line, qstr block) {
+    mp_obj_exception_t *self = mp_obj_exception_get_native(self_in);
+
+    // Try to allocate memory for the traceback, with fallback to emergency traceback object
+    if (self->traceback == NULL || self->traceback == (mp_obj_traceback_t *)&mp_const_empty_traceback_obj) {
+        self->traceback = m_new_obj_maybe(mp_obj_traceback_t);
+        if (self->traceback == NULL) {
+            self->traceback = &MP_STATE_VM(mp_emergency_traceback_obj);
+        }
+        // populate traceback object
+        *self->traceback = mp_const_empty_traceback_obj;
+    }
+
+    // append the provided traceback info to traceback data
+    // if memory allocation fails (eg because gc is locked), just return
+    if (self->traceback->data == NULL) {
+        self->traceback->data = m_new_maybe(size_t, TRACEBACK_ENTRY_LEN);
+        if (self->traceback->data == NULL) {
+            #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+            if (mp_emergency_exception_buf_size >= (mp_int_t)(EMG_BUF_TRACEBACK_OFFSET + EMG_BUF_TRACEBACK_SIZE)) {
+                // There is room in the emergency buffer for traceback data
+                size_t *tb = (size_t *)((uint8_t *)MP_STATE_VM(mp_emergency_exception_buf)
+                    + EMG_BUF_TRACEBACK_OFFSET);
+                self->traceback->data = tb;
+                self->traceback->alloc = EMG_BUF_TRACEBACK_SIZE / sizeof(size_t);
+            } else {
+                // Can't allocate and no room in emergency buffer
+                return;
+            }
+            #else
+            // Can't allocate
+            return;
+            #endif
+        } else {
+            // Allocated the traceback data on the heap
+            self->traceback->alloc = TRACEBACK_ENTRY_LEN;
+        }
+        self->traceback->len = 0;
+    } else if (self->traceback->len + TRACEBACK_ENTRY_LEN > self->traceback->alloc) {
+        #if MICROPY_ENABLE_EMERGENCY_EXCEPTION_BUF
+        if (self->traceback->data == (size_t *)MP_STATE_VM(mp_emergency_exception_buf)) {
+            // Can't resize the emergency buffer
+            return;
+        }
+        #endif
+        // be conservative with growing traceback data
+        size_t *tb_data = m_renew_maybe(size_t, self->traceback->data, self->traceback->alloc,
+            self->traceback->alloc + TRACEBACK_ENTRY_LEN, true);
+        if (tb_data == NULL) {
+            return;
+        }
+        self->traceback->data = tb_data;
+        self->traceback->alloc += TRACEBACK_ENTRY_LEN;
+    }
+
+    size_t *tb_data = &self->traceback->data[self->traceback->len];
+    self->traceback->len += TRACEBACK_ENTRY_LEN;
+    tb_data[0] = file;
+    tb_data[1] = line;
+    tb_data[2] = block;
+}
+
+void mp_obj_exception_get_traceback(mp_obj_t self_in, size_t *n, size_t **values) {
+    mp_obj_exception_t *self = mp_obj_exception_get_native(self_in);
+
+    if (self->traceback == NULL) {
+        *n = 0;
+        *values = NULL;
+    } else {
+        *n = self->traceback->len;
+        *values = self->traceback->data;
+    }
+}
+
+#if MICROPY_PY_SYS_EXC_INFO
+STATIC const mp_obj_namedtuple_type_t code_type_obj = {
+    .base = {
+        .base = {
+            .type = &mp_type_type
+        },
+        .flags = MP_TYPE_FLAG_EXTENDED,
+        .name = MP_QSTR_code,
+        .print = namedtuple_print,
+        .make_new = namedtuple_make_new,
+        .parent = &mp_type_tuple,
+        .attr = namedtuple_attr,
+        MP_TYPE_EXTENDED_FIELDS(
+            .unary_op = mp_obj_tuple_unary_op,
+            .binary_op = mp_obj_tuple_binary_op,
+            .subscr = mp_obj_tuple_subscr,
+            .getiter = mp_obj_tuple_getiter,
+            ),
+    },
+    .n_fields = 15,
+    .fields = {
+        MP_QSTR_co_argcount,
+        MP_QSTR_co_kwonlyargcount,
+        MP_QSTR_co_nlocals,
+        MP_QSTR_co_stacksize,
+        MP_QSTR_co_flags,
+        MP_QSTR_co_code,
+        MP_QSTR_co_consts,
+        MP_QSTR_co_names,
+        MP_QSTR_co_varnames,
+        MP_QSTR_co_freevars,
+        MP_QSTR_co_cellvars,
+        MP_QSTR_co_filename,
+        MP_QSTR_co_name,
+        MP_QSTR_co_firstlineno,
+        MP_QSTR_co_lnotab,
+    },
+};
+
+STATIC mp_obj_t code_make_new(qstr file, qstr block) {
+    mp_obj_t elems[15] = {
+        mp_obj_new_int(0),             // co_argcount
+        mp_obj_new_int(0),             // co_kwonlyargcount
+        mp_obj_new_int(0),             // co_nlocals
+        mp_obj_new_int(0),             // co_stacksize
+        mp_obj_new_int(0),             // co_flags
+        mp_obj_new_bytearray(0, NULL), // co_code
+        mp_obj_new_tuple(0, NULL),     // co_consts
+        mp_obj_new_tuple(0, NULL),     // co_names
+        mp_obj_new_tuple(0, NULL),     // co_varnames
+        mp_obj_new_tuple(0, NULL),     // co_freevars
+        mp_obj_new_tuple(0, NULL),     // co_cellvars
+        MP_OBJ_NEW_QSTR(file),         // co_filename
+        MP_OBJ_NEW_QSTR(block),        // co_name
+        mp_obj_new_int(1),             // co_firstlineno
+        mp_obj_new_bytearray(0, NULL), // co_lnotab
+    };
+
+    return namedtuple_make_new((const mp_obj_type_t *)&code_type_obj, 15, 0, elems);
+}
+
+STATIC const mp_obj_namedtuple_type_t frame_type_obj = {
+    .base = {
+        .base = {
+            .type = &mp_type_type
+        },
+        .name = MP_QSTR_frame,
+        .print = namedtuple_print,
+        .make_new = namedtuple_make_new,
+        .parent = &mp_type_tuple,
+        .attr = namedtuple_attr,
+        MP_TYPE_EXTENDED_FIELDS(
+            .unary_op = mp_obj_tuple_unary_op,
+            .binary_op = mp_obj_tuple_binary_op,
+            .subscr = mp_obj_tuple_subscr,
+            .getiter = mp_obj_tuple_getiter,
+            ),
+    },
+    .n_fields = 8,
+    .fields = {
+        MP_QSTR_f_back,
+        MP_QSTR_f_builtins,
+        MP_QSTR_f_code,
+        MP_QSTR_f_globals,
+        MP_QSTR_f_lasti,
+        MP_QSTR_f_lineno,
+        MP_QSTR_f_locals,
+        MP_QSTR_f_trace,
+    },
+};
+
+STATIC mp_obj_t frame_make_new(mp_obj_t f_code, int f_lineno) {
+    mp_obj_t elems[8] = {
+        mp_const_none,             // f_back
+        mp_obj_new_dict(0),        // f_builtins
+        f_code,                    // f_code
+        mp_obj_new_dict(0),        // f_globals
+        mp_obj_new_int(0),         // f_lasti
+        mp_obj_new_int(f_lineno),  // f_lineno
+        mp_obj_new_dict(0),        // f_locals
+        mp_const_none,             // f_trace
+    };
+
+    return namedtuple_make_new((const mp_obj_type_t *)&frame_type_obj, 8, 0, elems);
+}
+
+STATIC const mp_obj_namedtuple_type_t traceback_type_obj = {
+    .base = {
+        .base = {
+            .type = &mp_type_type
+        },
+        .flags = MP_TYPE_FLAG_EXTENDED,
+        .name = MP_QSTR_traceback,
+        .print = namedtuple_print,
+        .make_new = namedtuple_make_new,
+        .parent = &mp_type_tuple,
+        .attr = namedtuple_attr,
+        MP_TYPE_EXTENDED_FIELDS(
+            .unary_op = mp_obj_tuple_unary_op,
+            .binary_op = mp_obj_tuple_binary_op,
+            .subscr = mp_obj_tuple_subscr,
+            .getiter = mp_obj_tuple_getiter,
+            ),
+    },
+    .n_fields = 4,
+    .fields = {
+        MP_QSTR_tb_frame,
+        MP_QSTR_tb_lasti,
+        MP_QSTR_tb_lineno,
+        MP_QSTR_tb_next,
+    },
+};
+
+STATIC mp_obj_t traceback_from_values(size_t *values, mp_obj_t tb_next) {
+    int lineno = values[1];
+
+    mp_obj_t elems[4] = {
+        frame_make_new(code_make_new(values[0], values[2]), lineno),
+        mp_obj_new_int(0),
+        mp_obj_new_int(lineno),
+        tb_next,
+    };
+
+    return namedtuple_make_new((const mp_obj_type_t *)&traceback_type_obj, 4, 0, elems);
+};
+
+mp_obj_t mp_obj_exception_get_traceback_obj(mp_obj_t self_in) {
+    mp_obj_exception_t *self = MP_OBJ_TO_PTR(self_in);
+
+    if (!mp_obj_is_exception_instance(self)) {
+        return mp_const_none;
+    }
+
+    size_t n, *values;
+    mp_obj_exception_get_traceback(self, &n, &values);
+    if (n == 0) {
+        return mp_const_none;
+    }
+
+    mp_obj_t tb_next = mp_const_none;
+
+    for (size_t i = 0; i < n; i += 3) {
+        tb_next = traceback_from_values(&values[i], tb_next);
+    }
+
+    return tb_next;
+}
+#endif