svn commit: r190853 - in head/sys: amd64/include i386/include
Ed Schouten
ed at FreeBSD.org
Wed Apr 8 12:06:48 PDT 2009
Author: ed
Date: Wed Apr 8 19:06:47 2009
New Revision: 190853
URL: http://svn.freebsd.org/changeset/base/190853
Log:
Implement __bswap16() without using inline assembly.
Most compilers nowadays (including GCC) are smart enough to know what's
going on and generate more efficient code anyway.
Submitted by: Christoph Mallon <christoph.mallon at gmx.de>
Modified:
head/sys/amd64/include/endian.h
head/sys/i386/include/endian.h
Modified: head/sys/amd64/include/endian.h
==============================================================================
--- head/sys/amd64/include/endian.h Wed Apr 8 18:30:42 2009 (r190852)
+++ head/sys/amd64/include/endian.h Wed Apr 8 19:06:47 2009 (r190853)
@@ -135,26 +135,6 @@ __extension__ ({ register __uint64_t __X
#endif /* __OPTIMIZE__ */
-#define __byte_swap_word_var(x) \
-__extension__ ({ register __uint16_t __X = (x); \
- __asm ("xchgb %h0, %b0" : "+Q" (__X)); \
- __X; })
-
-#ifdef __OPTIMIZE__
-
-#define __byte_swap_word_const(x) \
- ((((x) & 0xff00) >> 8) | \
- (((x) & 0x00ff) << 8))
-
-#define __byte_swap_word(x) (__builtin_constant_p(x) ? \
- __byte_swap_word_const(x) : __byte_swap_word_var(x))
-
-#else /* __OPTIMIZE__ */
-
-#define __byte_swap_word(x) __byte_swap_word_var(x)
-
-#endif /* __OPTIMIZE__ */
-
static __inline __uint64_t
__bswap64(__uint64_t _x)
{
@@ -172,8 +152,7 @@ __bswap32(__uint32_t _x)
static __inline __uint16_t
__bswap16(__uint16_t _x)
{
-
- return (__byte_swap_word(_x));
+ return (_x << 8 | _x >> 8);
}
#define __htonl(x) __bswap32(x)
Modified: head/sys/i386/include/endian.h
==============================================================================
--- head/sys/i386/include/endian.h Wed Apr 8 18:30:42 2009 (r190852)
+++ head/sys/i386/include/endian.h Wed Apr 8 19:06:47 2009 (r190853)
@@ -109,26 +109,6 @@ __extension__ ({ register __uint32_t __X
#endif /* __OPTIMIZE__ */
-#define __byte_swap_word_var(x) \
-__extension__ ({ register __uint16_t __X = (x); \
- __asm ("xchgb %h0, %b0" : "+q" (__X)); \
- __X; })
-
-#ifdef __OPTIMIZE__
-
-#define __byte_swap_word_const(x) \
- ((((x) & 0xff00) >> 8) | \
- (((x) & 0x00ff) << 8))
-
-#define __byte_swap_word(x) (__builtin_constant_p(x) ? \
- __byte_swap_word_const(x) : __byte_swap_word_var(x))
-
-#else /* __OPTIMIZE__ */
-
-#define __byte_swap_word(x) __byte_swap_word_var(x)
-
-#endif /* __OPTIMIZE__ */
-
static __inline __uint64_t
__bswap64(__uint64_t _x)
{
@@ -149,8 +129,7 @@ __bswap32(__uint32_t _x)
static __inline __uint16_t
__bswap16(__uint16_t _x)
{
-
- return (__byte_swap_word(_x));
+ return (_x << 8 | _x >> 8);
}
#define __htonl(x) __bswap32(x)
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