The Tor Browser: media/libpng/arm/arm

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revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     2 /* arm_init.c - NEON optimised filter functions

     3  *

     4  * Copyright (c) 2014 Glenn Randers-Pehrson

     5  * Written by Mans Rullgard, 2011.

     6  * Last changed in libpng 1.6.10 [March 6, 2014]

     7  *

     8  * This code is released under the libpng license.

     9  * For conditions of distribution and use, see the disclaimer

    10  * and license in png.h

    11  */

    12 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are

    13  * called.

    14  */

    15 #define _POSIX_SOURCE 1

    17 #include "../pngpriv.h"

    19 #ifdef PNG_READ_SUPPORTED

    20 #if PNG_ARM_NEON_OPT > 0

    21 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */

    22 /* WARNING: it is strongly recommended that you do not build libpng with

    23  * run-time checks for CPU features if at all possible.  In the case of the ARM

    24  * NEON instructions there is no processor-specific way of detecting the

    25  * presense of the required support, therefore run-time detectioon is extremely

    26  * OS specific.

    27  *

    28  * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing

    29  * a fragment of C source code which defines the png_have_neon function.  There

    30  * are a number of implementations in contrib/arm-neon, but the only one that

    31  * has partial support is contrib/arm-neon/linux.c - a generic Linux

    32  * implementation which reads /proc/cpufino.

    33  */

    34 #ifndef PNG_ARM_NEON_FILE

    35 #  ifdef __linux__

    36 #     define PNG_ARM_NEON_FILE "linux.c"

    37 #  endif

    38 #endif

    40 #ifdef PNG_ARM_NEON_FILE

    42 #include <signal.h> /* for sig_atomic_t */

    43 static int png_have_neon(png_structp png_ptr);

    44 #include PNG_ARM_NEON_FILE

    46 #else  /* PNG_ARM_NEON_FILE */

    47 #  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"

    48 #endif /* PNG_ARM_NEON_FILE */

    49 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */

    51 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED

    52 #  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"

    53 #endif

    55 void

    56 png_init_filter_functions_neon(png_structp pp, unsigned int bpp)

    57 {

    58    /* The switch statement is compiled in for ARM_NEON_API, the call to

    59     * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined

    60     * the check is only performed if the API has not set the NEON option on

    61     * or off explicitly.  In this case the check controls what happens.

    62     *

    63     * If the CHECK is not compiled in and the option is UNSET the behavior prior

    64     * to 1.6.7 was to use the NEON code - this was a bug caused by having the

    65     * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,

    66     * as documented in png.h

    67     */

    68 #ifdef PNG_ARM_NEON_API_SUPPORTED

    69    switch ((pp->options >> PNG_ARM_NEON) & 3)

    70    {

    71       case PNG_OPTION_UNSET:

    72          /* Allow the run-time check to execute if it has been enabled -

    73           * thus both API and CHECK can be turned on.  If it isn't supported

    74           * this case will fall through to the 'default' below, which just

    75           * returns.

    76           */

    77 #endif /* PNG_ARM_NEON_API_SUPPORTED */

    78 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED

    79          {

    80             static volatile sig_atomic_t no_neon = -1; /* not checked */

    82             if (no_neon < 0)

    83                no_neon = !png_have_neon(pp);

    85             if (no_neon)

    86                return;

    87          }

    88 #ifdef PNG_ARM_NEON_API_SUPPORTED

    89          break;

    90 #endif

    91 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */

    93 #ifdef PNG_ARM_NEON_API_SUPPORTED

    94       default: /* OFF or INVALID */

    95          return;

    97       case PNG_OPTION_ON:

    98          /* Option turned on */

    99          break;

   100    }

   101 #endif

   103    /* IMPORTANT: any new external functions used here must be declared using

   104     * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the

   105     * 'prefix' option to configure works:

   106     *

   107     *    ./configure --with-libpng-prefix=foobar_

   108     *

   109     * Verify you have got this right by running the above command, doing a build

   110     * and examining pngprefix.h; it must contain a #define for every external

   111     * function you add.  (Notice that this happens automatically for the

   112     * initialization function.)

   113     */

   114    pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;

   116    if (bpp == 3)

   117    {

   118       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;

   119       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;

   120       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =

   121          png_read_filter_row_paeth3_neon;

   122    }

   124    else if (bpp == 4)

   125    {

   126       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;

   127       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;

   128       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =

   129           png_read_filter_row_paeth4_neon;

   130    }

   131 }

   132 #endif /* PNG_ARM_NEON_OPT > 0 */

   133 #endif /* PNG_READ_SUPPORTED */

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