workbench/libs/png/arm/arm_init.c

   1
   2 /* arm_init.c - NEON optimised filter functions
   3  *
   4  * Copyright (c) 2018 Cosmin Truta
   5  * Copyright (c) 2014,2016 Glenn Randers-Pehrson
   6  * Written by Mans Rullgard, 2011.
   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
  13 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
  14  * called.
  15  */
  16 #define _POSIX_SOURCE 1
  17
  18 #include "../pngpriv.h"
  19
  20 #ifdef PNG_READ_SUPPORTED
  21
  22 #if PNG_ARM_NEON_OPT > 0
  23 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */
  24 /* WARNING: it is strongly recommended that you do not build libpng with
  25  * run-time checks for CPU features if at all possible.  In the case of the ARM
  26  * NEON instructions there is no processor-specific way of detecting the
  27  * presence of the required support, therefore run-time detection is extremely
  28  * OS specific.
  29  *
  30  * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing
  31  * a fragment of C source code which defines the png_have_neon function.  There
  32  * are a number of implementations in contrib/arm-neon, but the only one that
  33  * has partial support is contrib/arm-neon/linux.c - a generic Linux
  34  * implementation which reads /proc/cpufino.
  35  */
  36 #ifndef PNG_ARM_NEON_FILE
  37 #  ifdef __linux__
  38 #     define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c"
  39 #  endif
  40 #endif
  41
  42 #ifdef PNG_ARM_NEON_FILE
  43
  44 #include <signal.h> /* for sig_atomic_t */
  45 static int png_have_neon(png_structp png_ptr);
  46 #include PNG_ARM_NEON_FILE
  47
  48 #else  /* PNG_ARM_NEON_FILE */
  49 #  error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks"
  50 #endif /* PNG_ARM_NEON_FILE */
  51 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
  52
  53 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
  54 #  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
  55 #endif
  56
  57 void
  58 png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
  59 {
  60    /* The switch statement is compiled in for ARM_NEON_API, the call to
  61     * png_have_neon is compiled in for ARM_NEON_CHECK.  If both are defined
  62     * the check is only performed if the API has not set the NEON option on
  63     * or off explicitly.  In this case the check controls what happens.
  64     *
  65     * If the CHECK is not compiled in and the option is UNSET the behavior prior
  66     * to 1.6.7 was to use the NEON code - this was a bug caused by having the
  67     * wrong order of the 'ON' and 'default' cases.  UNSET now defaults to OFF,
  68     * as documented in png.h
  69     */
  70    png_debug(1, "in png_init_filter_functions_neon");
  71 #ifdef PNG_ARM_NEON_API_SUPPORTED
  72    switch ((pp->options >> PNG_ARM_NEON) & 3)
  73    {
  74       case PNG_OPTION_UNSET:
  75          /* Allow the run-time check to execute if it has been enabled -
  76           * thus both API and CHECK can be turned on.  If it isn't supported
  77           * this case will fall through to the 'default' below, which just
  78           * returns.
  79           */
  80 #endif /* PNG_ARM_NEON_API_SUPPORTED */
  81 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED
  82          {
  83             static volatile sig_atomic_t no_neon = -1; /* not checked */
  84
  85             if (no_neon < 0)
  86                no_neon = !png_have_neon(pp);
  87
  88             if (no_neon)
  89                return;
  90          }
  91 #ifdef PNG_ARM_NEON_API_SUPPORTED
  92          break;
  93 #endif
  94 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */
  95
  96 #ifdef PNG_ARM_NEON_API_SUPPORTED
  97       default: /* OFF or INVALID */
  98          return;
  99
 100       case PNG_OPTION_ON:
 101          /* Option turned on */
 102          break;
 103    }
 104 #endif
 105
 106    /* IMPORTANT: any new external functions used here must be declared using
 107     * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
 108     * 'prefix' option to configure works:
 109     *
 110     *    ./configure --with-libpng-prefix=foobar_
 111     *
 112     * Verify you have got this right by running the above command, doing a build
 113     * and examining pngprefix.h; it must contain a #define for every external
 114     * function you add.  (Notice that this happens automatically for the
 115     * initialization function.)
 116     */
 117    pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
 118
 119    if (bpp == 3)
 120    {
 121       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
 122       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
 123       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
 124          png_read_filter_row_paeth3_neon;
 125    }
 126
 127    else if (bpp == 4)
 128    {
 129       pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
 130       pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
 131       pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
 132           png_read_filter_row_paeth4_neon;
 133    }
 134 }
 135 #endif /* PNG_ARM_NEON_OPT > 0 */
 136 #endif /* READ */