Author: tijl
Date: Fri Mar 9 11:48:56 2012
New Revision: 232721
URL: http://svn.freebsd.org/changeset/base/232721
Log:
Clean up x86 endian.h:
- 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
Modified:
head/sys/x86/include/endian.h
Modified: head/sys/x86/include/endian.h
==============================================================================
--- head/sys/x86/include/endian.h Fri Mar 9 09:32:20 2012
(r232720)
+++ head/sys/x86/include/endian.h Fri Mar 9 11:48:56 2012
(r232721)
@@ -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_const(_x) (__uint16_t)((_x) << 8 | (_x) >> 8)
-
-#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 __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))
+
+#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 __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_ */
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