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Description
Documentation
The current documentation for ctypes bit fields is very limited and doesn't cover the definition order. AFAICT this is:
Little endian - LSB first -> MSB last
Big endian - MSB first -> LSB last
Native - ??? This is LSB first -> MSB last on x86 but is that just because it's a little endian architecture?
For example:
class BigOnes(BigEndianStructure):
_pack_ = 1
_fields_ = (
("bit_0", c_uint16, 1), # MSBit
("bit_1", c_uint16, 1),
("bit_2", c_uint16, 1),
("bit_3", c_uint16, 1),
("nibble_1", c_uint16, 4),
("nibble_2", c_uint16, 4),
("nibble_3", c_uint16, 4), # LSBit
("byte_3", c_uint16, 8), # MSByte
("byte_4", c_uint16, 8), # LSByte
)
Versus:
class LittleOnes(LittleEndianStructure):
_pack_ = 1
_fields_ = (
("bit_0", c_uint16, 1), # LSBit
("bit_1", c_uint16, 1),
("bit_2", c_uint16, 1),
("bit_3", c_uint16, 1),
("nibble_1", c_uint16, 4),
("nibble_2", c_uint16, 4),
("nibble_3", c_uint16, 4), # MSBit
("byte_3", c_uint16, 8), # LSByte
("byte_4", c_uint16, 8), # MSByte
)