From 9630376dbca0202321f2aae6ef88ef75cdb5374e Mon Sep 17 00:00:00 2001 From: Damien George Date: Mon, 7 May 2018 13:36:52 +1000 Subject: [PATCH] py/mpconfig.h: Be stricter when autodetecting machine endianness. This patch changes 2 things in the endianness detection: 1. Don't assume that __BYTE_ORDER__ not being __ORDER_LITTLE_ENDIAN__ means that the machine is big endian, so add an explicit check that this macro is indeed __ORDER_BIG_ENDIAN__ (same with __BYTE_ORDER, __LITTLE_ENDIAN and __BIG_ENDIAN). A machine could have PDP endianness. 2. Remove the checks which base their autodetection decision on whether any little or big endian macros are defined (eg __LITTLE_ENDIAN__ or __BIG_ENDIAN__). Just because a system defines these does not mean it has that endianness. See issue #3760. --- py/mpconfig.h | 15 ++++++--------- 1 file changed, 6 insertions(+), 9 deletions(-) diff --git a/py/mpconfig.h b/py/mpconfig.h index 532b54ab0b..c42fe78536 100644 --- a/py/mpconfig.h +++ b/py/mpconfig.h @@ -1256,29 +1256,26 @@ typedef double mp_float_t; #elif defined(MP_ENDIANNESS_BIG) #define MP_ENDIANNESS_LITTLE (!MP_ENDIANNESS_BIG) #else - // Endiannes not defined by port so try to autodetect it. + // Endianness not defined by port so try to autodetect it. #if defined(__BYTE_ORDER__) #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__ #define MP_ENDIANNESS_LITTLE (1) - #else + #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__ #define MP_ENDIANNESS_LITTLE (0) #endif - #elif defined(__LITTLE_ENDIAN__) || defined(__LITTLE_ENDIAN) || defined (_LITTLE_ENDIAN) - #define MP_ENDIANNESS_LITTLE (1) - #elif defined(__BIG_ENDIAN__) || defined(__BIG_ENDIAN) || defined (_BIG_ENDIAN) - #define MP_ENDIANNESS_LITTLE (0) #else #include #if defined(__BYTE_ORDER) #if __BYTE_ORDER == __LITTLE_ENDIAN #define MP_ENDIANNESS_LITTLE (1) - #else + #elif __BYTE_ORDER == __BIG_ENDIAN #define MP_ENDIANNESS_LITTLE (0) #endif - #else - #error endianness not defined and cannot detect it #endif #endif + #ifndef MP_ENDIANNESS_LITTLE + #error endianness not defined and cannot detect it + #endif #define MP_ENDIANNESS_BIG (!MP_ENDIANNESS_LITTLE) #endif