loadable binary format creation, fixes #3

Author: ThomasWaldmann

esp32_ulp/link.py

@@ -0,0 +1,26 @@
+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
+

tests/00_run_tests.sh

@@ -1,6 +1,6 @@
 # export PYTHONPATH=.:$PYTHONPATH
 
-for file in opcodes assemble ; do
+for file in opcodes assemble link ; do
     echo testing $file...
     micropython $file.py
 done

tests/link.py

@@ -0,0 +1,15 @@
+from esp32_ulp.link import make_binary
+
+
+def test_make_binary():
+    text = b'\x12\x34\x56\x78'
+    data = b'\x11\x22\x33\x44'
+    bss_size = 40
+    bin = make_binary(text, data, bss_size)
+    assert len(bin) == 12 + len(text) + len(data)
+    assert bin.startswith(b'\x75\x6c\x70\x00')  # magic, LE
+    assert bin.endswith(text+data)
+
+
+test_make_binary()
+