[Spice-devel] [PATCH spice-protocol 1/2] macros: Use GCC built-ins to swap bytes

[Frediano Ziglio]

GCC introduced __builtin_bswapXX intrinsics in a quite old
version.
As version 2 and 3 are no more used nowadays instead of manually
craft these functions using assembly language use the new built-ins.

Signed-off-by: Frediano Ziglio <fziglio at redhat.com>
---
 spice/macros.h | 128 ++-------------------------------------------------------
 1 file changed, 4 insertions(+), 124 deletions(-)

diff --git a/spice/macros.h b/spice/macros.h
index 79d00ee..023fd6a 100644
--- a/spice/macros.h
+++ b/spice/macros.h
@@ -248,130 +248,10 @@
 
 /* Arch specific stuff for speed
  */
-#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
-#  if defined (__i386__)
-#    define SPICE_BYTESWAP16_IA32(val) \
-       (__extension__						\
-	({ register uint16_t __v, __x = ((uint16_t) (val));	\
-	   if (__builtin_constant_p (__x))			\
-	     __v = SPICE_BYTESWAP16_CONSTANT (__x);		\
-	   else							\
-	     __asm__ ("rorw $8, %w0"				\
-		      : "=r" (__v)				\
-		      : "0" (__x)				\
-		      : "cc");					\
-	    __v; }))
-#    if !defined (__i486__) && !defined (__i586__) \
-	&& !defined (__pentium__) && !defined (__i686__) \
-	&& !defined (__pentiumpro__) && !defined (__pentium4__)
-#       define SPICE_BYTESWAP32_IA32(val) \
-	  (__extension__					\
-	   ({ register uint32_t __v, __x = ((uint32_t) (val));	\
-	      if (__builtin_constant_p (__x))			\
-		__v = SPICE_BYTESWAP32_CONSTANT (__x);	\
-	      else						\
-		__asm__ ("rorw $8, %w0\n\t"			\
-			 "rorl $16, %0\n\t"			\
-			 "rorw $8, %w0"				\
-			 : "=r" (__v)				\
-			 : "0" (__x)				\
-			 : "cc");				\
-	      __v; }))
-#    else /* 486 and higher has bswap */
-#       define SPICE_BYTESWAP32_IA32(val) \
-	  (__extension__					\
-	   ({ register uint32_t __v, __x = ((uint32_t) (val));	\
-	      if (__builtin_constant_p (__x))			\
-		__v = SPICE_BYTESWAP32_CONSTANT (__x);	\
-	      else						\
-		__asm__ ("bswap %0"				\
-			 : "=r" (__v)				\
-			 : "0" (__x));				\
-	      __v; }))
-#    endif /* processor specific 32-bit stuff */
-#    define SPICE_BYTESWAP64_IA32(val) \
-       (__extension__							\
-	({ union { uint64_t __ll;					\
-		   uint32_t __l[2]; } __w, __r;				\
-	   __w.__ll = ((uint64_t) (val));				\
-	   if (__builtin_constant_p (__w.__ll))				\
-	     __r.__ll = SPICE_BYTESWAP64_CONSTANT (__w.__ll);		\
-	   else								\
-	     {								\
-	       __r.__l[0] = SPICE_BYTESWAP32 (__w.__l[1]);		\
-	       __r.__l[1] = SPICE_BYTESWAP32 (__w.__l[0]);		\
-	     }								\
-	   __r.__ll; }))
-     /* Possibly just use the constant version and let gcc figure it out? */
-#    define SPICE_BYTESWAP16(val) (SPICE_BYTESWAP16_IA32 (val))
-#    define SPICE_BYTESWAP32(val) (SPICE_BYTESWAP32_IA32 (val))
-#    define SPICE_BYTESWAP64(val) (SPICE_BYTESWAP64_IA32 (val))
-#  elif defined (__ia64__)
-#    define SPICE_BYTESWAP16_IA64(val) \
-       (__extension__						\
-	({ register uint16_t __v, __x = ((uint16_t) (val));	\
-	   if (__builtin_constant_p (__x))			\
-	     __v = SPICE_BYTESWAP16_CONSTANT (__x);		\
-	   else							\
-	     __asm__ __volatile__ ("shl %0 = %1, 48 ;;"		\
-				   "mux1 %0 = %0, @rev ;;"	\
-				    : "=r" (__v)		\
-				    : "r" (__x));		\
-	    __v; }))
-#    define SPICE_BYTESWAP32_IA64(val) \
-       (__extension__						\
-	 ({ register uint32_t __v, __x = ((uint32_t) (val));	\
-	    if (__builtin_constant_p (__x))			\
-	      __v = SPICE_BYTESWAP32_CONSTANT (__x);		\
-	    else						\
-	     __asm__ __volatile__ ("shl %0 = %1, 32 ;;"		\
-				   "mux1 %0 = %0, @rev ;;"	\
-				    : "=r" (__v)		\
-				    : "r" (__x));		\
-	    __v; }))
-#    define SPICE_BYTESWAP64_IA64(val) \
-       (__extension__						\
-	({ register uint64_t __v, __x = ((uint64_t) (val));	\
-	   if (__builtin_constant_p (__x))			\
-	     __v = SPICE_BYTESWAP64_CONSTANT (__x);		\
-	   else							\
-	     __asm__ __volatile__ ("mux1 %0 = %1, @rev ;;"	\
-				   : "=r" (__v)			\
-				   : "r" (__x));		\
-	   __v; }))
-#    define SPICE_BYTESWAP16(val) (SPICE_BYTESWAP16_IA64 (val))
-#    define SPICE_BYTESWAP32(val) (SPICE_BYTESWAP32_IA64 (val))
-#    define SPICE_BYTESWAP64(val) (SPICE_BYTESWAP64_IA64 (val))
-#  elif defined (__x86_64__)
-#    define SPICE_BYTESWAP32_X86_64(val) \
-       (__extension__						\
-	 ({ register uint32_t __v, __x = ((uint32_t) (val));	\
-	    if (__builtin_constant_p (__x))			\
-	      __v = SPICE_BYTESWAP32_CONSTANT (__x);		\
-	    else						\
-	     __asm__ ("bswapl %0"				\
-		      : "=r" (__v)				\
-		      : "0" (__x));				\
-	    __v; }))
-#    define SPICE_BYTESWAP64_X86_64(val) \
-       (__extension__						\
-	({ register uint64_t __v, __x = ((uint64_t) (val));	\
-	   if (__builtin_constant_p (__x))			\
-	     __v = SPICE_BYTESWAP64_CONSTANT (__x);		\
-	   else							\
-	     __asm__ ("bswapq %0"				\
-		      : "=r" (__v)				\
-		      : "0" (__x));				\
-	   __v; }))
-     /* gcc seems to figure out optimal code for this on its own */
-#    define SPICE_BYTESWAP16(val) (SPICE_BYTESWAP16_CONSTANT (val))
-#    define SPICE_BYTESWAP32(val) (SPICE_BYTESWAP32_X86_64 (val))
-#    define SPICE_BYTESWAP64(val) (SPICE_BYTESWAP64_X86_64 (val))
-#  else /* generic gcc */
-#    define SPICE_BYTESWAP16(val) (SPICE_BYTESWAP16_CONSTANT (val))
-#    define SPICE_BYTESWAP32(val) (SPICE_BYTESWAP32_CONSTANT (val))
-#    define SPICE_BYTESWAP64(val) (SPICE_BYTESWAP64_CONSTANT (val))
-#  endif
+#if defined (__GNUC__) && (__GNUC__ >= 4) && defined (__OPTIMIZE__)
+#  define SPICE_BYTESWAP16(val) __builtin_bswap16(val)
+#  define SPICE_BYTESWAP32(val) __builtin_bswap32(val)
+#  define SPICE_BYTESWAP64(val) __builtin_bswap64(val)
 #else /* generic */
 #  define SPICE_BYTESWAP16(val) (SPICE_BYTESWAP16_CONSTANT (val))
 #  define SPICE_BYTESWAP32(val) (SPICE_BYTESWAP32_CONSTANT (val))
-- 
2.14.3