IABSD.fr/xenocara/lib/libpng/powerpc/powerpc_init.c

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• Author : ajacoutot
  Date : 2025-09-17 14:44:36
  Hash : e8681e75
  Message : Import source for libpng 1.6.50 (verbatim).

• lib/libpng/powerpc/powerpc_init.c

• /* powerpc_init.c - POWERPC optimised filter functions
   *
   * Copyright (c) 2018 Cosmin Truta
   * Copyright (c) 2017 Glenn Randers-Pehrson
   * Written by Vadim Barkov, 2017.
   *
   * This code is released under the libpng license.
   * For conditions of distribution and use, see the disclaimer
   * and license in png.h
   */
  
  /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
   * called.
   */
  #define _POSIX_SOURCE 1
  
  #include <stdio.h>
  #include "../pngpriv.h"
  
  #ifdef PNG_READ_SUPPORTED
  
  #if PNG_POWERPC_VSX_OPT > 0
  #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
  /* WARNING: it is strongly recommended that you do not build libpng with
   * run-time checks for CPU features if at all possible.  In the case of the PowerPC
   * VSX instructions there is no processor-specific way of detecting the
   * presence of the required support, therefore run-time detection is extremely
   * OS specific.
   *
   * You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
   * a fragment of C source code which defines the png_have_vsx function.  There
   * are a number of implementations in contrib/powerpc-vsx, but the only one that
   * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
   * implementation which reads /proc/cpufino.
   */
  #ifndef PNG_POWERPC_VSX_FILE
  #  ifdef __linux__
  #     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
  #  endif
  #endif
  
  #ifdef PNG_POWERPC_VSX_FILE
  
  #include <signal.h> /* for sig_atomic_t */
  static int png_have_vsx(png_structp png_ptr);
  #include PNG_POWERPC_VSX_FILE
  
  #else  /* PNG_POWERPC_VSX_FILE */
  #  error PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks
  #endif /* PNG_POWERPC_VSX_FILE */
  #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
  
  void
  png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
  {
     /* The switch statement is compiled in for POWERPC_VSX_API, the call to
      * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
      * the check is only performed if the API has not set the PowerPC option on
      * or off explicitly. In this case the check controls what happens.
      */
  
  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
     switch ((pp->options >> PNG_POWERPC_VSX) & 3)
     {
        case PNG_OPTION_UNSET:
           /* Allow the run-time check to execute if it has been enabled -
            * thus both API and CHECK can be turned on.  If it isn't supported
            * this case will fall through to the 'default' below, which just
            * returns.
            */
  #endif /* PNG_POWERPC_VSX_API_SUPPORTED */
  #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
           {
              static volatile sig_atomic_t no_vsx = -1; /* not checked */
  
              if (no_vsx < 0)
                 no_vsx = !png_have_vsx(pp);
  
              if (no_vsx)
                 return;
           }
  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
           break;
  #endif
  #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
  
  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
        default: /* OFF or INVALID */
           return;
  
        case PNG_OPTION_ON:
           /* Option turned on */
           break;
     }
  #endif
  
     /* IMPORTANT: any new internal functions used here must be declared using
      * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
      * 'prefix' option to configure works:
      *
      *    ./configure --with-libpng-prefix=foobar_
      *
      * Verify you have got this right by running the above command, doing a build
      * and examining pngprefix.h; it must contain a #define for every external
      * function you add.  (Notice that this happens automatically for the
      * initialization function.)
      */
     pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
  
     if (bpp == 3)
     {
        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
     }
  
     else if (bpp == 4)
     {
        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
     }
  }
  #endif /* PNG_POWERPC_VSX_OPT > 0 */
  #endif /* READ */