]> git.sesse.net Git - ffmpeg/blobdiff - libavcodec/cabac.h
Add FFMPEG_ prefix to all multiple inclusion guards.
[ffmpeg] / libavcodec / cabac.h
index b17667cd5a140c7677119543ba16079e55c77ec4..d7f58d72848f7ef1ae5e254d19c637d4f5f8555c 100644 (file)
@@ -17,7 +17,6 @@
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
  */
 
 /**
  * Context Adaptive Binary Arithmetic Coder.
  */
 
+#ifndef FFMPEG_CABAC_H
+#define FFMPEG_CABAC_H
+
+#include "bitstream.h"
 
 //#undef NDEBUG
 #include <assert.h>
+#ifdef ARCH_X86
+#include "x86_cpu.h"
+#endif
 
 #define CABAC_BITS 16
 #define CABAC_MASK ((1<<CABAC_BITS)-1)
 #define BRANCHLESS_CABAC_DECODER 1
-#define CMOV_IS_FAST 1
+//#define ARCH_X86_DISABLED 1
 
 typedef struct CABACContext{
     int low;
@@ -48,7 +54,7 @@ typedef struct CABACContext{
 }CABACContext;
 
 extern uint8_t ff_h264_mlps_state[4*64];
-extern uint8_t ff_h264_lps_range[4][2*64];  ///< rangeTabLPS
+extern uint8_t ff_h264_lps_range[4*2*64];  ///< rangeTabLPS
 extern uint8_t ff_h264_mps_state[2*64];     ///< transIdxMPS
 extern uint8_t ff_h264_lps_state[2*64];     ///< transIdxLPS
 extern const uint8_t ff_h264_norm_shift[512];
@@ -84,6 +90,7 @@ static inline void renorm_cabac_encoder(CABACContext *c){
     }
 }
 
+#if 0
 static void put_cabac(CABACContext *c, uint8_t * const state, int bit){
     int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + *state];
 
@@ -253,6 +260,7 @@ static void put_cabac_ueg(CABACContext *c, uint8_t * state, int v, int max, int
             put_cabac_bypass(c, sign);
     }
 }
+#endif /* 0 */
 
 static void refill(CABACContext *c){
 #if CABAC_BITS == 16
@@ -264,6 +272,7 @@ static void refill(CABACContext *c){
     c->bytestream+= CABAC_BITS/8;
 }
 
+#if ! ( defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) )
 static void refill2(CABACContext *c){
     int i, x;
 
@@ -281,6 +290,7 @@ static void refill2(CABACContext *c){
     c->low += x<<i;
     c->bytestream+= CABAC_BITS/8;
 }
+#endif
 
 static inline void renorm_cabac_decoder(CABACContext *c){
     while(c->range < 0x100){
@@ -360,23 +370,29 @@ static inline void renorm_cabac_decoder_once(CABACContext *c){
         refill(c);
 }
 
-static int always_inline get_cabac_inline(CABACContext *c, uint8_t * const state){
+static av_always_inline int get_cabac_inline(CABACContext *c, uint8_t * const state){
     //FIXME gcc generates duplicate load/stores for c->low and c->range
-#if defined(ARCH_X86) && !defined(PIC)
-    int bit;
-
 #define LOW          "0"
 #define RANGE        "4"
+#ifdef ARCH_X86_64
+#define BYTESTART   "16"
+#define BYTE        "24"
+#define BYTEEND     "32"
+#else
 #define BYTESTART   "12"
 #define BYTE        "16"
 #define BYTEEND     "20"
+#endif
+#if defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS)
+    int bit;
+
 #ifndef BRANCHLESS_CABAC_DECODER
     asm volatile(
-        "movzbl (%1), %%eax                     \n\t"
+        "movzbl (%1), %0                        \n\t"
         "movl "RANGE    "(%2), %%ebx            \n\t"
         "movl "RANGE    "(%2), %%edx            \n\t"
         "andl $0xC0, %%ebx                      \n\t"
-        "movzbl "MANGLE(ff_h264_lps_range)"(%%eax, %%ebx, 2), %%esi\n\t"
+        "movzbl "MANGLE(ff_h264_lps_range)"(%0, %%ebx, 2), %%esi\n\t"
         "movl "LOW      "(%2), %%ebx            \n\t"
 //eax:state ebx:low, edx:range, esi:RangeLPS
         "subl %%esi, %%edx                      \n\t"
@@ -398,19 +414,19 @@ static int always_inline get_cabac_inline(CABACContext *c, uint8_t * const state
         "shl %%cl, %%edx                        \n\t"
         "shl %%cl, %%ebx                        \n\t"
 #endif
-        "movzbl "MANGLE(ff_h264_mps_state)"(%%eax), %%ecx   \n\t"
+        "movzbl "MANGLE(ff_h264_mps_state)"(%0), %%ecx   \n\t"
         "movb %%cl, (%1)                        \n\t"
 //eax:state ebx:low, edx:range, esi:RangeLPS
         "test %%bx, %%bx                        \n\t"
         " jnz 2f                                \n\t"
-        "movl "BYTE     "(%2), %%esi            \n\t"
+        "mov  "BYTE     "(%2), %%"REG_S"        \n\t"
         "subl $0xFFFF, %%ebx                    \n\t"
-        "movzwl (%%esi), %%ecx                  \n\t"
+        "movzwl (%%"REG_S"), %%ecx              \n\t"
         "bswap %%ecx                            \n\t"
         "shrl $15, %%ecx                        \n\t"
-        "addl $2, %%esi                         \n\t"
+        "add  $2, %%"REG_S"                     \n\t"
         "addl %%ecx, %%ebx                      \n\t"
-        "movl %%esi, "BYTE    "(%2)             \n\t"
+        "mov  %%"REG_S", "BYTE    "(%2)         \n\t"
         "jmp 2f                                 \n\t"
         "1:                                     \n\t"
 //eax:state ebx:low, edx:range, esi:RangeLPS
@@ -419,19 +435,19 @@ static int always_inline get_cabac_inline(CABACContext *c, uint8_t * const state
         "movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx   \n\t"
         "shll %%cl, %%ebx                       \n\t"
         "shll %%cl, %%edx                       \n\t"
-        "movzbl "MANGLE(ff_h264_lps_state)"(%%eax), %%ecx   \n\t"
+        "movzbl "MANGLE(ff_h264_lps_state)"(%0), %%ecx   \n\t"
         "movb %%cl, (%1)                        \n\t"
-        "addl $1, %%eax                         \n\t"
+        "add  $1, %0                            \n\t"
         "test %%bx, %%bx                        \n\t"
         " jnz 2f                                \n\t"
 
-        "movl "BYTE     "(%2), %%ecx            \n\t"
-        "movzwl (%%ecx), %%esi                  \n\t"
+        "mov  "BYTE     "(%2), %%"REG_c"        \n\t"
+        "movzwl (%%"REG_c"), %%esi              \n\t"
         "bswap %%esi                            \n\t"
         "shrl $15, %%esi                        \n\t"
         "subl $0xFFFF, %%esi                    \n\t"
-        "addl $2, %%ecx                         \n\t"
-        "movl %%ecx, "BYTE    "(%2)             \n\t"
+        "add  $2, %%"REG_c"                     \n\t"
+        "mov  %%"REG_c", "BYTE    "(%2)         \n\t"
 
         "leal -1(%%ebx), %%ecx                  \n\t"
         "xorl %%ebx, %%ecx                      \n\t"
@@ -445,109 +461,111 @@ static int always_inline get_cabac_inline(CABACContext *c, uint8_t * const state
         "2:                                     \n\t"
         "movl %%edx, "RANGE    "(%2)            \n\t"
         "movl %%ebx, "LOW      "(%2)            \n\t"
-        :"=&a"(bit) //FIXME this is fragile gcc either runs out of registers or misscompiles it (for example if "+a"(bit) or "+m"(*state) is used
+        :"=&a"(bit) //FIXME this is fragile gcc either runs out of registers or miscompiles it (for example if "+a"(bit) or "+m"(*state) is used
         :"r"(state), "r"(c)
-        : "%ecx", "%ebx", "%edx", "%esi", "memory"
+        : "%"REG_c, "%ebx", "%edx", "%"REG_S, "memory"
     );
     bit&=1;
 #else /* BRANCHLESS_CABAC_DECODER */
-    asm volatile(
-        "movzbl (%1), %%eax                     \n\t"
-        "movl "RANGE    "(%2), %%ebx            \n\t"
-        "movl "RANGE    "(%2), %%edx            \n\t"
-        "andl $0xC0, %%ebx                      \n\t"
-        "movzbl "MANGLE(ff_h264_lps_range)"(%%eax, %%ebx, 2), %%esi\n\t"
-        "movl "LOW      "(%2), %%ebx            \n\t"
-//eax:state ebx:low, edx:range, esi:RangeLPS
-        "subl %%esi, %%edx                      \n\t"
-#ifdef CMOV_IS_FAST
-        "movl %%edx, %%ecx                      \n\t"
-        "shl $17, %%edx                         \n\t"
-        "cmpl %%ebx, %%edx                      \n\t"
-        "cmova %%ecx, %%esi                     \n\t"
-        "sbbl %%ecx, %%ecx                      \n\t"
-        "andl %%ecx, %%edx                      \n\t"
-        "subl %%edx, %%ebx                      \n\t"
-        "xorl %%ecx, %%eax                      \n\t"
-#else /* CMOV_IS_FAST */
-FIXTHIS
-        "movl %%edx, %%ecx                      \n\t"
-        "subl %%ebx, %%edx                      \n\t"
-        "sarl $31, %%edx                        \n\t" //lps_mask
-        "subl %%ecx, %%esi                      \n\t" //RangeLPS - range
-        "andl %%edx, %%esi                      \n\t" //(RangeLPS - range)&lps_mask
-        "addl %%ecx, %%esi                      \n\t" //new range
-        "andl %%edx, %%ecx                      \n\t"
-        "subl %%ecx, %%ebx                      \n\t"
-        "xorl %%edx, %%eax                      \n\t"
-#endif /* CMOV_IS_FAST */
 
-//eax:state ebx:low edx:mask esi:range
 
-//eax:bit ebx:low esi:range
+#if defined HAVE_FAST_CMOV
+#define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
+        "mov    "tmp"       , %%ecx                                     \n\t"\
+        "shl    $17         , "tmp"                                     \n\t"\
+        "cmp    "low"       , "tmp"                                     \n\t"\
+        "cmova  %%ecx       , "range"                                   \n\t"\
+        "sbb    %%ecx       , %%ecx                                     \n\t"\
+        "and    %%ecx       , "tmp"                                     \n\t"\
+        "sub    "tmp"       , "low"                                     \n\t"\
+        "xor    %%ecx       , "ret"                                     \n\t"
+#else /* HAVE_FAST_CMOV */
+#define BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
+        "mov    "tmp"       , %%ecx                                     \n\t"\
+        "shl    $17         , "tmp"                                     \n\t"\
+        "sub    "low"       , "tmp"                                     \n\t"\
+        "sar    $31         , "tmp"                                     \n\t" /*lps_mask*/\
+        "sub    %%ecx       , "range"                                   \n\t" /*RangeLPS - range*/\
+        "and    "tmp"       , "range"                                   \n\t" /*(RangeLPS - range)&lps_mask*/\
+        "add    %%ecx       , "range"                                   \n\t" /*new range*/\
+        "shl    $17         , %%ecx                                     \n\t"\
+        "and    "tmp"       , %%ecx                                     \n\t"\
+        "sub    %%ecx       , "low"                                     \n\t"\
+        "xor    "tmp"       , "ret"                                     \n\t"
+#endif /* HAVE_FAST_CMOV */
+
+
+#define BRANCHLESS_GET_CABAC(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
+        "movzbl "statep"    , "ret"                                     \n\t"\
+        "mov    "range"     , "tmp"                                     \n\t"\
+        "and    $0xC0       , "range"                                   \n\t"\
+        "movzbl "MANGLE(ff_h264_lps_range)"("ret", "range", 2), "range" \n\t"\
+        "sub    "range"     , "tmp"                                     \n\t"\
+        BRANCHLESS_GET_CABAC_UPDATE(ret, cabac, statep, low, lowword, range, tmp, tmpbyte)\
+        "movzbl " MANGLE(ff_h264_norm_shift) "("range"), %%ecx          \n\t"\
+        "shl    %%cl        , "range"                                   \n\t"\
+        "movzbl "MANGLE(ff_h264_mlps_state)"+128("ret"), "tmp"          \n\t"\
+        "mov    "tmpbyte"   , "statep"                                  \n\t"\
+        "shl    %%cl        , "low"                                     \n\t"\
+        "test   "lowword"   , "lowword"                                 \n\t"\
+        " jnz   1f                                                      \n\t"\
+        "mov "BYTE"("cabac"), %%"REG_c"                                 \n\t"\
+        "movzwl (%%"REG_c")     , "tmp"                                 \n\t"\
+        "bswap  "tmp"                                                   \n\t"\
+        "shr    $15         , "tmp"                                     \n\t"\
+        "sub    $0xFFFF     , "tmp"                                     \n\t"\
+        "add    $2          , %%"REG_c"                                 \n\t"\
+        "mov    %%"REG_c"   , "BYTE    "("cabac")                       \n\t"\
+        "lea    -1("low")   , %%ecx                                     \n\t"\
+        "xor    "low"       , %%ecx                                     \n\t"\
+        "shr    $15         , %%ecx                                     \n\t"\
+        "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx            \n\t"\
+        "neg    %%ecx                                                   \n\t"\
+        "add    $7          , %%ecx                                     \n\t"\
+        "shl    %%cl        , "tmp"                                     \n\t"\
+        "add    "tmp"       , "low"                                     \n\t"\
+        "1:                                                             \n\t"
 
-        "movzbl " MANGLE(ff_h264_norm_shift) "(%%esi), %%ecx   \n\t"
-        "shll %%cl, %%esi                       \n\t"
-        "movzbl "MANGLE(ff_h264_mlps_state)"+128(%%eax), %%edx   \n\t"
-        "movb %%dl, (%1)                        \n\t"
+    asm volatile(
+        "movl "RANGE    "(%2), %%esi            \n\t"
+        "movl "LOW      "(%2), %%ebx            \n\t"
+        BRANCHLESS_GET_CABAC("%0", "%2", "(%1)", "%%ebx", "%%bx", "%%esi", "%%edx", "%%dl")
         "movl %%esi, "RANGE    "(%2)            \n\t"
-        "shll %%cl, %%ebx                       \n\t"
         "movl %%ebx, "LOW      "(%2)            \n\t"
-        "test %%bx, %%bx                        \n\t"
-        " jnz 1f                                \n\t"
-
-        "movl "BYTE     "(%2), %%ecx            \n\t"
-        "movzwl (%%ecx), %%esi                  \n\t"
-        "bswap %%esi                            \n\t"
-        "shrl $15, %%esi                        \n\t"
-        "subl $0xFFFF, %%esi                    \n\t"
-        "addl $2, %%ecx                         \n\t"
-        "movl %%ecx, "BYTE    "(%2)             \n\t"
 
-        "leal -1(%%ebx), %%ecx                  \n\t"
-        "xorl %%ebx, %%ecx                      \n\t"
-        "shrl $15, %%ecx                        \n\t"
-        "movzbl " MANGLE(ff_h264_norm_shift) "(%%ecx), %%ecx   \n\t"
-        "neg %%ecx                              \n\t"
-        "add $7, %%ecx                          \n\t"
-
-        "shll %%cl , %%esi                      \n\t"
-        "addl %%esi, %%ebx                      \n\t"
-        "movl %%ebx, "LOW      "(%2)            \n\t"
-        "1:                                     \n\t"
         :"=&a"(bit)
         :"r"(state), "r"(c)
-        : "%ecx", "%ebx", "%edx", "%esi", "memory"
+        : "%"REG_c, "%ebx", "%edx", "%esi", "memory"
     );
     bit&=1;
 #endif /* BRANCHLESS_CABAC_DECODER */
-#else /* ARCH_X86 */
+#else /* defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) */
     int s = *state;
-    int RangeLPS= ff_h264_lps_range[0][2*(c->range&0xC0) + s];
-    int bit, lps_mask attribute_unused;
+    int RangeLPS= ff_h264_lps_range[2*(c->range&0xC0) + s];
+    int bit, lps_mask av_unused;
 
     c->range -= RangeLPS;
 #ifndef BRANCHLESS_CABAC_DECODER
-    if(c->low < (c->range<<17)){
+    if(c->low < (c->range<<(CABAC_BITS+1))){
         bit= s&1;
         *state= ff_h264_mps_state[s];
         renorm_cabac_decoder_once(c);
     }else{
         bit= ff_h264_norm_shift[RangeLPS];
-        c->low -= (c->range<<17);
+        c->low -= (c->range<<(CABAC_BITS+1));
         *state= ff_h264_lps_state[s];
         c->range = RangeLPS<<bit;
         c->low <<= bit;
         bit= (s&1)^1;
 
-        if(!(c->low & 0xFFFF)){
+        if(!(c->low & CABAC_MASK)){
             refill2(c);
         }
     }
 #else /* BRANCHLESS_CABAC_DECODER */
-    lps_mask= ((c->range<<17) - c->low)>>31;
+    lps_mask= ((c->range<<(CABAC_BITS+1)) - c->low)>>31;
 
-    c->low -= (c->range<<17) & lps_mask;
+    c->low -= (c->range<<(CABAC_BITS+1)) & lps_mask;
     c->range += (RangeLPS - c->range) & lps_mask;
 
     s^=lps_mask;
@@ -560,11 +578,11 @@ FIXTHIS
     if(!(c->low & CABAC_MASK))
         refill2(c);
 #endif /* BRANCHLESS_CABAC_DECODER */
-#endif /* ARCH_X86 */
+#endif /* defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) */
     return bit;
 }
 
-static int __attribute((noinline)) get_cabac_noinline(CABACContext *c, uint8_t * const state){
+static int av_noinline get_cabac_noinline(CABACContext *c, uint8_t * const state){
     return get_cabac_inline(c,state);
 }
 
@@ -573,28 +591,217 @@ static int get_cabac(CABACContext *c, uint8_t * const state){
 }
 
 static int get_cabac_bypass(CABACContext *c){
+#if 0 //not faster
+    int bit;
+    asm volatile(
+        "movl "RANGE    "(%1), %%ebx            \n\t"
+        "movl "LOW      "(%1), %%eax            \n\t"
+        "shl $17, %%ebx                         \n\t"
+        "add %%eax, %%eax                       \n\t"
+        "sub %%ebx, %%eax                       \n\t"
+        "cdq                                    \n\t"
+        "and %%edx, %%ebx                       \n\t"
+        "add %%ebx, %%eax                       \n\t"
+        "test %%ax, %%ax                        \n\t"
+        " jnz 1f                                \n\t"
+        "movl "BYTE     "(%1), %%"REG_b"        \n\t"
+        "subl $0xFFFF, %%eax                    \n\t"
+        "movzwl (%%"REG_b"), %%ecx              \n\t"
+        "bswap %%ecx                            \n\t"
+        "shrl $15, %%ecx                        \n\t"
+        "addl $2, %%"REG_b"                     \n\t"
+        "addl %%ecx, %%eax                      \n\t"
+        "movl %%"REG_b", "BYTE     "(%1)        \n\t"
+        "1:                                     \n\t"
+        "movl %%eax, "LOW      "(%1)            \n\t"
+
+        :"=&d"(bit)
+        :"r"(c)
+        : "%eax", "%"REG_b, "%ecx", "memory"
+    );
+    return bit+1;
+#else
     int range;
     c->low += c->low;
 
     if(!(c->low & CABAC_MASK))
         refill(c);
 
-    range= c->range<<17;
+    range= c->range<<(CABAC_BITS+1);
     if(c->low < range){
         return 0;
     }else{
         c->low -= range;
         return 1;
     }
+#endif
+}
+
+
+static av_always_inline int get_cabac_bypass_sign(CABACContext *c, int val){
+#if defined(ARCH_X86) && !(defined(PIC) && defined(__GNUC__))
+    asm volatile(
+        "movl "RANGE    "(%1), %%ebx            \n\t"
+        "movl "LOW      "(%1), %%eax            \n\t"
+        "shl $17, %%ebx                         \n\t"
+        "add %%eax, %%eax                       \n\t"
+        "sub %%ebx, %%eax                       \n\t"
+        "cdq                                    \n\t"
+        "and %%edx, %%ebx                       \n\t"
+        "add %%ebx, %%eax                       \n\t"
+        "xor %%edx, %%ecx                       \n\t"
+        "sub %%edx, %%ecx                       \n\t"
+        "test %%ax, %%ax                        \n\t"
+        " jnz 1f                                \n\t"
+        "mov  "BYTE     "(%1), %%"REG_b"        \n\t"
+        "subl $0xFFFF, %%eax                    \n\t"
+        "movzwl (%%"REG_b"), %%edx              \n\t"
+        "bswap %%edx                            \n\t"
+        "shrl $15, %%edx                        \n\t"
+        "add  $2, %%"REG_b"                     \n\t"
+        "addl %%edx, %%eax                      \n\t"
+        "mov  %%"REG_b", "BYTE     "(%1)        \n\t"
+        "1:                                     \n\t"
+        "movl %%eax, "LOW      "(%1)            \n\t"
+
+        :"+c"(val)
+        :"r"(c)
+        : "%eax", "%"REG_b, "%edx", "memory"
+    );
+    return val;
+#else
+    int range, mask;
+    c->low += c->low;
+
+    if(!(c->low & CABAC_MASK))
+        refill(c);
+
+    range= c->range<<(CABAC_BITS+1);
+    c->low -= range;
+    mask= c->low >> 31;
+    range &= mask;
+    c->low += range;
+    return (val^mask)-mask;
+#endif
+}
+
+//FIXME the x86 code from this file should be moved into i386/h264 or cabac something.c/h (note ill kill you if you move my code away from under my fingers before iam finished with it!)
+//FIXME use some macros to avoid duplicatin get_cabac (cannot be done yet as that would make optimization work hard)
+#if defined(ARCH_X86) && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS)
+static int decode_significance_x86(CABACContext *c, int max_coeff, uint8_t *significant_coeff_ctx_base, int *index){
+    void *end= significant_coeff_ctx_base + max_coeff - 1;
+    int minusstart= -(int)significant_coeff_ctx_base;
+    int minusindex= 4-(int)index;
+    int coeff_count;
+    asm volatile(
+        "movl "RANGE    "(%3), %%esi            \n\t"
+        "movl "LOW      "(%3), %%ebx            \n\t"
+
+        "2:                                     \n\t"
+
+        BRANCHLESS_GET_CABAC("%%edx", "%3", "(%1)", "%%ebx", "%%bx", "%%esi", "%%eax", "%%al")
+
+        "test $1, %%edx                         \n\t"
+        " jz 3f                                 \n\t"
+
+        BRANCHLESS_GET_CABAC("%%edx", "%3", "61(%1)", "%%ebx", "%%bx", "%%esi", "%%eax", "%%al")
+
+        "mov  %2, %%"REG_a"                     \n\t"
+        "movl %4, %%ecx                         \n\t"
+        "add  %1, %%"REG_c"                     \n\t"
+        "movl %%ecx, (%%"REG_a")                \n\t"
+
+        "test $1, %%edx                         \n\t"
+        " jnz 4f                                \n\t"
+
+        "add  $4, %%"REG_a"                     \n\t"
+        "mov  %%"REG_a", %2                     \n\t"
+
+        "3:                                     \n\t"
+        "add  $1, %1                            \n\t"
+        "cmp  %5, %1                            \n\t"
+        " jb 2b                                 \n\t"
+        "mov  %2, %%"REG_a"                     \n\t"
+        "movl %4, %%ecx                         \n\t"
+        "add  %1, %%"REG_c"                     \n\t"
+        "movl %%ecx, (%%"REG_a")                \n\t"
+        "4:                                     \n\t"
+        "add  %6, %%eax                         \n\t"
+        "shr $2, %%eax                          \n\t"
+
+        "movl %%esi, "RANGE    "(%3)            \n\t"
+        "movl %%ebx, "LOW      "(%3)            \n\t"
+        :"=&a"(coeff_count), "+r"(significant_coeff_ctx_base), "+m"(index)\
+        :"r"(c), "m"(minusstart), "m"(end), "m"(minusindex)\
+        : "%"REG_c, "%ebx", "%edx", "%esi", "memory"\
+    );
+    return coeff_count;
 }
 
+static int decode_significance_8x8_x86(CABACContext *c, uint8_t *significant_coeff_ctx_base, int *index, uint8_t *sig_off){
+    int minusindex= 4-(int)index;
+    int coeff_count;
+    long last=0;
+    asm volatile(
+        "movl "RANGE    "(%3), %%esi            \n\t"
+        "movl "LOW      "(%3), %%ebx            \n\t"
+
+        "mov %1, %%"REG_D"                      \n\t"
+        "2:                                     \n\t"
+
+        "mov %6, %%"REG_a"                      \n\t"
+        "movzbl (%%"REG_a", %%"REG_D"), %%edi   \n\t"
+        "add %5, %%"REG_D"                      \n\t"
+
+        BRANCHLESS_GET_CABAC("%%edx", "%3", "(%%"REG_D")", "%%ebx", "%%bx", "%%esi", "%%eax", "%%al")
+
+        "mov %1, %%edi                          \n\t"
+        "test $1, %%edx                         \n\t"
+        " jz 3f                                 \n\t"
+
+        "movzbl "MANGLE(last_coeff_flag_offset_8x8)"(%%edi), %%edi\n\t"
+        "add %5, %%"REG_D"                      \n\t"
+
+        BRANCHLESS_GET_CABAC("%%edx", "%3", "15(%%"REG_D")", "%%ebx", "%%bx", "%%esi", "%%eax", "%%al")
+
+        "mov %2, %%"REG_a"                      \n\t"
+        "mov %1, %%edi                          \n\t"
+        "movl %%edi, (%%"REG_a")                \n\t"
+
+        "test $1, %%edx                         \n\t"
+        " jnz 4f                                \n\t"
+
+        "add $4, %%"REG_a"                      \n\t"
+        "mov %%"REG_a", %2                      \n\t"
+
+        "3:                                     \n\t"
+        "addl $1, %%edi                         \n\t"
+        "mov %%edi, %1                          \n\t"
+        "cmpl $63, %%edi                        \n\t"
+        " jb 2b                                 \n\t"
+        "mov %2, %%"REG_a"                      \n\t"
+        "movl %%edi, (%%"REG_a")                \n\t"
+        "4:                                     \n\t"
+        "addl %4, %%eax                         \n\t"
+        "shr $2, %%eax                          \n\t"
+
+        "movl %%esi, "RANGE    "(%3)            \n\t"
+        "movl %%ebx, "LOW      "(%3)            \n\t"
+        :"=&a"(coeff_count),"+m"(last), "+m"(index)\
+        :"r"(c), "m"(minusindex), "m"(significant_coeff_ctx_base), "m"(sig_off)\
+        : "%"REG_c, "%ebx", "%edx", "%esi", "%"REG_D, "memory"\
+    );
+    return coeff_count;
+}
+#endif /* defined(ARCH_X86) && && defined(HAVE_7REGS) && defined(HAVE_EBX_AVAILABLE) && !defined(BROKEN_RELOCATIONS) */
+
 /**
  *
  * @return the number of bytes read or 0 if no end
  */
 static int get_cabac_terminate(CABACContext *c){
     c->range -= 2;
-    if(c->low < c->range<<17){
+    if(c->low < c->range<<(CABAC_BITS+1)){
         renorm_cabac_decoder_once(c);
         return 0;
     }else{
@@ -602,8 +809,9 @@ static int get_cabac_terminate(CABACContext *c){
     }
 }
 
+#if 0
 /**
- * get (truncated) unnary binarization.
+ * Get (truncated) unary binarization.
  */
 static int get_cabac_u(CABACContext *c, uint8_t * state, int max, int max_index, int truncated){
     int i;
@@ -657,3 +865,6 @@ static int get_cabac_ueg(CABACContext *c, uint8_t * state, int max, int is_signe
     }else
         return i;
 }
+#endif /* 0 */
+
+#endif /* FFMPEG_CABAC_H */