link.py

#
# This file is part of the micropython-esp32-ulp project,
# https://github.com/micropython/micropython-esp32-ulp
#
# SPDX-FileCopyrightText: 2018-2023, the micropython-esp32-ulp authors, see AUTHORS file.
# SPDX-License-Identifier: MIT

from uctypes import struct, addressof, LITTLE_ENDIAN, UINT16, UINT32


def make_binary(text, data, bss_size):
    if not isinstance(text, bytes):
        raise TypeError('text section must be binary bytes')
    if not isinstance(data, bytes):
        raise TypeError('data section must be binary bytes')
    binary_header_struct_def = dict(
        magic = 0 | UINT32,
        text_offset = 4 | UINT16,
        text_size = 6 | UINT16,
        data_size = 8 | UINT16,
        bss_size = 10 | UINT16,
    )
    header = bytearray(12)
    h = struct(addressof(header), binary_header_struct_def, LITTLE_ENDIAN)
    # https://github.com/espressif/esp-idf/blob/master/components/ulp/ld/esp32.ulp.ld
    # ULP program binary should have the following format (all values little-endian):
    h.magic = 0x00706c75  # (4 bytes)
    h.text_offset = 12  # offset of .text section from binary start (2 bytes)
    h.text_size = len(text)  # size of .text section (2 bytes)
    h.data_size = len(data)  # size of .data section (2 bytes)
    h.bss_size = bss_size  # size of .bss section (2 bytes)
    return bytes(header) + text + data