svn commit: r232721 - head/sys/x86/include

[John Baldwin]

On Friday, March 09, 2012 6:48:56 am Tijl Coosemans wrote:
> 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

BTW, I think I found an old "bug" in this file.  The _gen() variants
should only use the _gen() variants of smaller types rather than using
the version that re-checks __build_constant_p() I think.  That is:

Index: x86/include/endian.h
===================================================================
--- endian.h	(revision 233184)
+++ endian.h	(working copy)
@@ -65,9 +65,9 @@
 
 #define	__bswap16_gen(x)	(__uint16_t)((x) << 8 | (x) >> 8)
 #define	__bswap32_gen(x)		\
-	(((__uint32_t)__bswap16(x) << 16) | __bswap16((x) >> 16))
+	(((__uint32_t)__bswap16_gen(x) << 16) | __bswap16_gen((x) >> 16))
 #define	__bswap64_gen(x)		\
-	(((__uint64_t)__bswap32(x) << 32) | __bswap32((x) >> 32))
+	(((__uint64_t)__bswap32_gen(x) << 32) | __bswap32_gen((x) >> 32))
 
 #ifdef __GNUCLIKE_BUILTIN_CONSTANT_P
 #define	__bswap16(x)				\

I ran into this while porting the __builtin_constant_p() functionality
over to ia64.

-- 
John Baldwin