The Tor Browser: media/libtheora/lib/arm/armcpu.c@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /********************************************************************

     2  *                                                                  *

     3  * THIS FILE IS PART OF THE OggTheora SOFTWARE CODEC SOURCE CODE.   *

     4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *

     5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *

     6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *

     7  *                                                                  *

     8  * THE Theora SOURCE CODE IS COPYRIGHT (C) 2002-2010                *

     9  * by the Xiph.Org Foundation and contributors http://www.xiph.org/ *

    10  *                                                                  *

    11  ********************************************************************

    13  CPU capability detection for ARM processors.

    15  function:

    16   last mod: $Id: cpu.c 17344 2010-07-21 01:42:18Z tterribe $

    18  ********************************************************************/

    20 #include "armcpu.h"

    22 #if !defined(OC_ARM_ASM)|| \

    23  !defined(OC_ARM_ASM_EDSP)&&!defined(OC_ARM_ASM_ARMV6)&& \

    24  !defined(OC_ARM_ASM_NEON)

    25 ogg_uint32_t oc_cpu_flags_get(void){

    26   return 0;

    27 }

    29 #elif defined(_MSC_VER)

    30 /*For GetExceptionCode() and EXCEPTION_ILLEGAL_INSTRUCTION.*/

    31 # define WIN32_LEAN_AND_MEAN

    32 # define WIN32_EXTRA_LEAN

    33 # include <windows.h>

    35 ogg_uint32_t oc_cpu_flags_get(void){

    36   ogg_uint32_t flags;

    37   flags=0;

    38   /*MSVC has no inline __asm support for ARM, but it does let you __emit

    39      instructions via their assembled hex code.

    40     All of these instructions should be essentially nops.*/

    41 # if defined(OC_ARM_ASM_EDSP)

    42   __try{

    43     /*PLD [r13]*/

    44     __emit(0xF5DDF000);

    45     flags|=OC_CPU_ARM_EDSP;

    46   }

    47   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){

    48     /*Ignore exception.*/

    49   }

    50 #  if defined(OC_ARM_ASM_MEDIA)

    51   __try{

    52     /*SHADD8 r3,r3,r3*/

    53     __emit(0xE6333F93);

    54     flags|=OC_CPU_ARM_MEDIA;

    55   }

    56   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){

    57     /*Ignore exception.*/

    58   }

    59 #   if defined(OC_ARM_ASM_NEON)

    60   __try{

    61     /*VORR q0,q0,q0*/

    62     __emit(0xF2200150);

    63     flags|=OC_CPU_ARM_NEON;

    64   }

    65   __except(GetExceptionCode()==EXCEPTION_ILLEGAL_INSTRUCTION){

    66     /*Ignore exception.*/

    67   }

    68 #   endif

    69 #  endif

    70 # endif

    71   return flags;

    72 }

    74 #elif defined(__linux__)

    75 # include <stdio.h>

    76 # include <stdlib.h>

    77 # include <string.h>

    79 ogg_uint32_t oc_cpu_flags_get(void){

    80   ogg_uint32_t  flags;

    81   FILE         *fin;

    82   flags=0;

    83   /*Reading /proc/self/auxv would be easier, but that doesn't work reliably on

    84      Android.

    85     This also means that detection will fail in Scratchbox.*/

    86   fin=fopen("/proc/cpuinfo","r");

    87   if(fin!=NULL){

    88     /*512 should be enough for anybody (it's even enough for all the flags that

    89        x86 has accumulated... so far).*/

    90     char buf[512];

    91     while(fgets(buf,511,fin)!=NULL){

    92       if(memcmp(buf,"Features",8)==0){

    93         char *p;

    94         p=strstr(buf," edsp");

    95         if(p!=NULL&&(p[5]==' '||p[5]=='\n'))flags|=OC_CPU_ARM_EDSP;

    96         p=strstr(buf," neon");

    97         if(p!=NULL&&(p[5]==' '||p[5]=='\n'))flags|=OC_CPU_ARM_NEON;

    98       }

    99       if(memcmp(buf,"CPU architecture:",17)==0){

   100         int version;

   101         version=atoi(buf+17);

   102         if(version>=6)flags|=OC_CPU_ARM_MEDIA;

   103       }

   104     }

   105     fclose(fin);

   106   }

   107   return flags;

   108 }

   110 #else

   111 /*The feature registers which can tell us what the processor supports are

   112    accessible in priveleged modes only, so we can't have a general user-space

   113    detection method like on x86.*/

   114 # error "Configured to use ARM asm but no CPU detection method available for " \

   115  "your platform.  Reconfigure with --disable-asm (or send patches)."

   116 #endif

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