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macros: Use GCC built-ins to swap bytes

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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@redhat.com>
Acked-by: Christophe Fergeau <cfergeau@redhat.com>
This commit is contained in:
Frediano Ziglio 2018-03-09 13:04:09 +00:00
parent 4250216baf
commit d1dca6450c
1 changed files with 4 additions and 124 deletions
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128
spice/macros.h
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@ -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))