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Clean up x86 endian.h:

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- Remove extern "C". There are no functions with external linkage here. [1]
- Rename bswapNN_const(x) to bswapNN_gen(x) to indicate that these macros
  are generic implementations that can take non-constant arguments. [1]
- Split up __GNUCLIKE_ASM && __GNUCLIKE_BUILTIN_CONSTANT_P and deal with
  each separately.
- Replace _LP64 with __amd64__ because asm instructions are machine
  dependent, not ABI dependent.

Submitted by:	bde [1]
Reviewed by:	bde
This commit is contained in:
Tijl Coosemans 2012-03-09 11:48:56 +00:00
parent 9ea99cd3b5
commit 0502467707
1 changed files with 36 additions and 43 deletions
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79
sys/x86/include/endian.h
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@ -36,10 +36,6 @@
#include <sys/cdefs.h>
#include <sys/_types.h>
#ifdef __cplusplus
extern "C" {
#endif
/*
* Define the order of 32-bit words in 64-bit words.
*/
@ -67,51 +63,63 @@ extern "C" {
#define BYTE_ORDER _BYTE_ORDER
#endif
#if defined(__GNUCLIKE_ASM) && defined(__GNUCLIKE_BUILTIN_CONSTANT_P)
#define __bswap16_gen(x) (__uint16_t)((x) << 8 | (x) >> 8)
#define __bswap32_gen(x) \
(((__uint32_t)__bswap16(x) << 16) | __bswap16((x) >> 16))
#define __bswap64_gen(x) \
(((__uint64_t)__bswap32(x) << 32) | __bswap32((x) >> 32))
#define __bswap16_const(_x) (__uint16_t)((_x) << 8 | (_x) >> 8)
#ifdef __GNUCLIKE_BUILTIN_CONSTANT_P
#define __bswap16(x) \
(__builtin_constant_p(x) ? \
__bswap16_gen((__uint16_t)(x)) : __bswap16_var(x))
#define __bswap32(x) \
(__builtin_constant_p(x) ? \
__bswap32_gen((__uint32_t)(x)) : __bswap32_var(x))
#define __bswap64(x) \
(__builtin_constant_p(x) ? \
__bswap64_gen((__uint64_t)(x)) : __bswap64_var(x))
#else
/* XXX these are broken for use in static initializers. */
#define __bswap16(x) __bswap16_var(x)
#define __bswap32(x) __bswap32_var(x)
#define __bswap64(x) __bswap64_var(x)
#endif
#define __bswap16(_x) \
(__builtin_constant_p(_x) ? \
__bswap16_const((__uint16_t)(_x)) : __bswap16_var(_x))
#define __bswap32_const(_x) \
(((__uint32_t)__bswap16(_x) << 16) | __bswap16((_x) >> 16))
#define __bswap32(_x) \
(__builtin_constant_p(_x) ? \
__bswap32_const((__uint32_t)(_x)) : __bswap32_var(_x))
#define __bswap64_const(_x) \
(((__uint64_t)__bswap32(_x) << 32) | __bswap32((_x) >> 32))
#define __bswap64(_x) \
(__builtin_constant_p(_x) ? \
__bswap64_const((__uint64_t)(_x)) : __bswap64_var(_x))
/* These are defined as functions to avoid multiple evaluation of x. */
static __inline __uint16_t
__bswap16_var(__uint16_t _x)
{
return (__bswap16_const(_x));
return (__bswap16_gen(_x));
}
static __inline __uint32_t
__bswap32_var(__uint32_t _x)
{
__asm ("bswap %0" : "+r" (_x));
#ifdef __GNUCLIKE_ASM
__asm("bswap %0" : "+r" (_x));
return (_x);
#else
return (__bswap32_gen(_x));
#endif
}
static __inline __uint64_t
__bswap64_var(__uint64_t _x)
{
#ifdef _LP64
__asm ("bswap %0" : "+r" (_x));
#if defined(__amd64__) && defined(__GNUCLIKE_ASM)
__asm("bswap %0" : "+r" (_x));
return (_x);
#else
return (__bswap64_const(_x));
/*
* It is important for the optimizations that the following is not
* really generic, but expands to 2 __bswap32_var()'s.
*/
return (__bswap64_gen(_x));
#endif
}
@ -120,19 +128,4 @@ __bswap64_var(__uint64_t _x)
#define __ntohl(x) __bswap32(x)
#define __ntohs(x) __bswap16(x)
#else /* !(__GNUCLIKE_ASM && __GNUCLIKE_BUILTIN_CONSTANT_P) */
/*
* No optimizations are available for this compiler. Fall back to
* non-optimized functions by defining the constant usually used to prevent
* redefinition.
*/
#define _BYTEORDER_FUNC_DEFINED
#endif /* __GNUCLIKE_ASM && __GNUCLIKE_BUILTIN_CONSTANT_P */
#ifdef __cplusplus
}
#endif
#endif /* !_MACHINE_ENDIAN_H_ */