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Code Issues Releases Activity

c std doesnt like negative shifts -> use asm

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Originally committed as revision 730 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2002-07-09 19:22:50 +00:00
parent df595131bb
commit ef5e74bbfd
1 changed files with 26 additions and 12 deletions
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38
libavcodec/common.h
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@ -165,11 +165,25 @@ inline void dprintf(const char* fmt,...) {}
#define MAX(a,b) ((a) > (b) ? (a) : (b))
#define MIN(a,b) ((a) > (b) ? (b) : (a))
#if defined ARCH_X86 && (__GNUC__ != 3 || __GNUC_MINOR__ > 1)
// inverse for shift optimization (gcc should do that ...)
#define INV32(a) (-a)
#ifdef ARCH_X86
// avoid +32 for shift optimization (gcc should do that ...)
static inline int32_t NEG_SSR32( int32_t a, int8_t s){
asm ("sarl %1, %0\n\t"
: "+r" (a)
: "ic" ((uint8_t)(-s))
);
return a;
}
static inline uint32_t NEG_USR32(uint32_t a, int8_t s){
asm ("shrl %1, %0\n\t"
: "+r" (a)
: "ic" ((uint8_t)(-s))
);
return a;
}
#else
#define INV32(a) (32-a)
#define NEG_SSR32(a,s) ((( int32_t)(a))>>(32-(s)))
#define NEG_USR32(a,s) (((uint32_t)(a))>>(32-(s)))
#endif
/* bit output */
@ -530,10 +544,10 @@ for examples see get_bits, show_bits, skip_bits, get_vlc
# define LAST_SKIP_CACHE(name, gb, num) ;
# define SHOW_UBITS(name, gb, num)\
(((uint32_t)name##_cache)>>INV32(num))
NEG_USR32(name##_cache, num)
# define SHOW_SBITS(name, gb, num)\
(((int32_t)name##_cache)>>INV32(num))
NEG_SSR32(name##_cache, num)
# define GET_CACHE(name, gb)\
((uint32_t)name##_cache)
@ -579,10 +593,10 @@ static inline int get_bits_count(GetBitContext *s){
# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
# define SHOW_UBITS(name, gb, num)\
(((uint32_t)name##_cache)>>INV32(num))
NEG_USR32(name##_cache, num)
# define SHOW_SBITS(name, gb, num)\
(((int32_t)name##_cache)>>INV32(num))
NEG_SSR32(name##_cache, num)
# define GET_CACHE(name, gb)\
((uint32_t)name##_cache)
@ -610,7 +624,7 @@ static inline int get_bits_count(GetBitContext *s){
# define UPDATE_CACHE(name, gb)\
if(name##_bit_count > 0){\
const uint32_t next= be2me_32( *name##_buffer_ptr );\
name##_cache0 |= next>>INV32(name##_bit_count);\
name##_cache0 |= NEG_USR32(next,name##_bit_count);\
name##_cache1 |= next<<name##_bit_count;\
name##_buffer_ptr++;\
name##_bit_count-= 32;\
@ -627,7 +641,7 @@ static inline int get_bits_count(GetBitContext *s){
#else
# define SKIP_CACHE(name, gb, num)\
name##_cache0 <<= (num);\
name##_cache0 |= name##_cache1 >>INV32(num);\
name##_cache0 |= NEG_USR32(name##_cache1,num);\
name##_cache1 <<= (num);
#endif
@ -644,10 +658,10 @@ static inline int get_bits_count(GetBitContext *s){
# define LAST_SKIP_CACHE(name, gb, num) SKIP_CACHE(name, gb, num)
# define SHOW_UBITS(name, gb, num)\
(((uint32_t)name##_cache0)>>INV32(num))
NEG_USR32(name##_cache0, num)
# define SHOW_SBITS(name, gb, num)\
(((int32_t)name##_cache0)>>INV32(num))
NEG_SSR32(name##_cache0, num)
# define GET_CACHE(name, gb)\
(name##_cache0)