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bytesex: more endianness detection hacks

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A few more tricks for sussing out endinanness, and add an ultimate
fallback option.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
H. Peter Anvin 2017-04-25 12:51:17 -07:00
parent 573112ee86
commit 53cd7c7bf0
2 changed files with 54 additions and 11 deletions
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38
include/bytesex.h
View File

@ -223,8 +223,42 @@ static inline uint64_t cpu_to_le64(uint64_t v)
#else /* not WORDS_LITTLEENDIAN or WORDS_BIGENDIAN */
#error "Update byteord.h to include arbitrary byte orders"
static inline uint16_t cpu_to_le16(uint16_t v)
{
union u16 {
uint16_t v;
uint8_t c[2];
} x;
uint8_t *cp = &x.c;
WRITESHORT(cp, v);
return x.v;
}
static inline uint32_t cpu_to_le32(uint32_t v)
{
union u32 {
uint32_t v;
uint8_t c[4];
} x;
uint8_t *cp = &x.c;
WRITELONG(cp, v);
return x.v;
}
static inline uint64_t cpu_to_le64(uint64_t v)
{
union u64 {
uint64_t v;
uint8_t c[8];
} x;
uint8_t *cp = &x.c;
WRITEDLONG(cp, v);
return x.v;
}
#endif
#endif /* NASM_BYTEORD_H */
#endif /* NASM_BYTESEX_H */

27
include/compiler.h
View File

@ -96,11 +96,20 @@
#endif
/*
* If we have BYTE_ORDER defined, trust it over what autoconf came up
* with, especially since autoconf obviously can't figure things out
* for a universal compiler.
* If we have BYTE_ORDER defined, or the compiler provides
* __BIG_ENDIAN__ or __LITTLE_ENDIAN__, trust it over what autoconf
* came up with, especially since autoconf obviously can't figure
* things out for a universal compiler.
*/
#if defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
#if defined(__BIG_ENDIAN__) && !defined(__LITTLE_ENDIAN__)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# define WORDS_BIGENDIAN 1
#elif defined(__LITTLE_ENDIAN__) && !defined(__BIG_ENDIAN__)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# define WORDS_LITTLEENDIAN 1
#elif defined(BYTE_ORDER) && defined(LITTLE_ENDIAN) && defined(BIG_ENDIAN)
# undef WORDS_LITTLEENDIAN
# undef WORDS_BIGENDIAN
# if BYTE_ORDER == LITTLE_ENDIAN
@ -112,15 +121,15 @@
/*
* Define this to 1 for faster performance if this is a littleendian
* platform which can do unaligned memory references. It is safe
* to leave it defined to 0 even if that is true.
* platform *and* it can do arbitrary unaligned memory references. It
* is safe to leave it defined to 0 even if that is true.
*/
#if defined(__386__) || defined(__i386__) || defined(__x86_64__) \
|| defined(_M_IX86) || defined(_M_X64)
# define X86_MEMORY 1
# ifndef WORDS_LITTLEENDIAN
# define WORDS_LITTLEENDIAN 1
# endif
# undef WORDS_BIGENDIAN
# undef WORDS_LITTLEENDIAN
# define WORDS_LITTLEENDIAN 1
#else
# define X86_MEMORY 0
#endif