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Member "pngcrush-1.8.13/arm_init.c" (27 Aug 2016, 4691 Bytes) of package /linux/privat/pngcrush-1.8.13.tar.gz:


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    1 
    2 /* arm_init.c - NEON optimised filter functions
    3  *
    4  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
    5  * Written by Mans Rullgard, 2011.
    6  * Last changed in libpng 1.6.22 [May 26, 2016]
    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
   16 
   17 #include "pngpriv.h"
   18 
   19 #ifdef PNG_READ_SUPPORTED
   20 
   21 #if PNG_ARM_NEON_OPT > 0
   22 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
   23 /* WARNING: it is strongly recommended that you do not build libpng with
   24  * run-time checks for CPU features if at all possible.  In the case of the ARM
   25  * NEON instructions there is no processor-specific way of detecting the
   26  * presence of the required support, therefore run-time detection is extremely
   27  * OS specific.
   28  *
   29  * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
   30  * a fragment of C source code which defines the png_have_neon function.  There
   31  * are a number of implementations in contrib/arm-neon, but the only one that
   32  * has partial support is contrib/arm-neon/linux.c - a generic Linux
   33  * implementation which reads /proc/cpufino.
   34  */
   35 #ifndef PNG_ARM_NEON_FILE
   36 #  ifdef __linux__
   37 #     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
   38 #  endif
   39 #endif
   40 
   41 #ifdef PNG_ARM_NEON_FILE
   42 
   43 #include <signal.h> /* for sig_atomic_t */
   44 static int png_have_neon(png_structp png_ptr);
   45 #include PNG_ARM_NEON_FILE
   46 
   47 #else  /* PNG_ARM_NEON_FILE */
   48 #  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
   49 #endif /* PNG_ARM_NEON_FILE */
   50 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
   51 
   52 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
   53 #  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
   54 #endif
   55 
   56 void
   57 png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
   58 {
   59    /* The switch statement is compiled in for ARM_NEON_API, the call to
   60     * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined
   61     * the check is only performed if the API has not set the NEON option on
   62     * or off explicitly.  In this case the check controls what happens.
   63     *
   64     * If the CHECK is not compiled in and the option is UNSET the behavior prior
   65     * to 1.6.7 was to use the NEON code - this was a bug caused by having the
   66     * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
   67     * as documented in png.h
   68     */
   69    png_debug(1, "in png_init_filter_functions_neon");
   70 #ifdef PNG_ARM_NEON_API_SUPPORTED
   71    switch ((pp->options >> PNG_ARM_NEON) & 3)
   72    {
   73       case PNG_OPTION_UNSET:
   74          /* Allow the run-time check to execute if it has been enabled -
   75           * thus both API and CHECK can be turned on.  If it isn't supported
   76           * this case will fall through to the 'default' below, which just
   77           * returns.
   78           */
   79 #endif /* PNG_ARM_NEON_API_SUPPORTED */
   80 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED
   81          {
   82             static volatile sig_atomic_t no_neon = -1; /* not checked */
   83 
   84             if (no_neon < 0)
   85                no_neon = !png_have_neon(pp);
   86 
   87             if (no_neon)
   88                return;
   89          }
   90 #ifdef PNG_ARM_NEON_API_SUPPORTED
   91          break;
   92 #endif
   93 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
   94 
   95 #ifdef PNG_ARM_NEON_API_SUPPORTED
   96       default: /* OFF or INVALID */
   97          return;
   98 
   99       case PNG_OPTION_ON:
  100          /* Option turned on */
  101          break;
  102    }
  103 #endif
  104 
  105    /* IMPORTANT: any new external functions used here must be declared using
  106     * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
  107     * 'prefix' option to configure works:
  108     *
  109     *    ./configure --with-libpng-prefix=foobar_
  110     *
  111     * Verify you have got this right by running the above command, doing a build
  112     * and examining pngprefix.h; it must contain a #define for every external
  113     * function you add.  (Notice that this happens automatically for the
  114     * initialization function.)
  115     */
  116    pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
  117 
  118    if (bpp == 3)
  119    {
  120       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
  121       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
  122       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
  123          png_read_filter_row_paeth3_neon;
  124    }
  125 
  126    else if (bpp == 4)
  127    {
  128       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
  129       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
  130       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
  131           png_read_filter_row_paeth4_neon;
  132    }
  133 }
  134 #endif /* PNG_ARM_NEON_OPT > 0 */
  135 #endif /* READ */