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py: Try to autodetect machine endianness when not defined by port.

This commit is contained in:
Damien George 2014-10-06 13:44:59 +00:00
parent 5a04e2cca8
commit a9bcd51dc7
1 changed files with 20 additions and 7 deletions
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23
py/mpconfig.h
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@ -434,14 +434,27 @@ typedef double mp_float_t;
// mp_int_t value with most significant bit set
#define WORD_MSBIT_HIGH (((mp_uint_t)1) << (BYTES_PER_WORD * 8 - 1))
#if !defined(MP_ENDIANNESS_LITTLE) && !defined(MP_ENDIANNESS_BIG)
// Just because most archs are such?
// Make sure both MP_ENDIANNESS_LITTLE and MP_ENDIANNESS_BIG are
// defined and that they are the opposite of each other.
#if defined(MP_ENDIANNESS_LITTLE)
#define MP_ENDIANNESS_BIG (!MP_ENDIANNESS_LITTLE)
#elif defined(MP_ENDIANNESS_BIG)
#define MP_ENDIANNESS_LITTLE (!MP_ENDIANNESS_BIG)
#else
// Endiannes not defined by port so try to autodetect it.
#if defined(__BYTE_ORDER__)
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define MP_ENDIANNESS_LITTLE (1)
#endif
// Ensure we don't accidentally set both endiannesses
#if MP_ENDIANNESS_BIG
#else
#define MP_ENDIANNESS_LITTLE (0)
#endif
#elif defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined (_BIG_ENDIAN)
#define MP_ENDIANNESS_LITTLE (0)
#else
#error endianness not defined and cannot detect it
#endif
#define MP_ENDIANNESS_BIG (!MP_ENDIANNESS_LITTLE)
#endif
// Make a pointer to RAM callable (eg set lower bit for Thumb code)
// (This scheme won't work if we want to mix Thumb and normal ARM code.)