1  
       2  /* powerpc_init.c - POWERPC optimised filter functions
       3   *
       4   * Copyright (c) 2018 Cosmin Truta
       5   * Copyright (c) 2017 Glenn Randers-Pehrson
       6   * Written by Vadim Barkov, 2017.
       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 <stdio.h>
      19  #include "../pngpriv.h"
      20  
      21  #ifdef PNG_READ_SUPPORTED
      22  
      23  #if PNG_POWERPC_VSX_OPT > 0
      24  #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
      25  /* WARNING: it is strongly recommended that you do not build libpng with
      26   * run-time checks for CPU features if at all possible.  In the case of the PowerPC
      27   * VSX instructions there is no processor-specific way of detecting the
      28   * presence of the required support, therefore run-time detection is extremely
      29   * OS specific.
      30   *
      31   * You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
      32   * a fragment of C source code which defines the png_have_vsx function.  There
      33   * are a number of implementations in contrib/powerpc-vsx, but the only one that
      34   * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
      35   * implementation which reads /proc/cpufino.
      36   */
      37  #ifndef PNG_POWERPC_VSX_FILE
      38  #  ifdef __linux__
      39  #     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
      40  #  endif
      41  #endif
      42  
      43  #ifdef PNG_POWERPC_VSX_FILE
      44  
      45  #include <signal.h> /* for sig_atomic_t */
      46  static int png_have_vsx(png_structp png_ptr);
      47  #include PNG_POWERPC_VSX_FILE
      48  
      49  #else  /* PNG_POWERPC_VSX_FILE */
      50  #  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
      51  #endif /* PNG_POWERPC_VSX_FILE */
      52  #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
      53  
      54  void
      55  png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
      56  {
      57     /* The switch statement is compiled in for POWERPC_VSX_API, the call to
      58      * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
      59      * the check is only performed if the API has not set the PowerPC option on
      60      * or off explicitly. In this case the check controls what happens.
      61      */
      62  
      63  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
      64     switch ((pp->options >> PNG_POWERPC_VSX) & 3)
      65     {
      66        case PNG_OPTION_UNSET:
      67           /* Allow the run-time check to execute if it has been enabled -
      68            * thus both API and CHECK can be turned on.  If it isn't supported
      69            * this case will fall through to the 'default' below, which just
      70            * returns.
      71            */
      72  #endif /* PNG_POWERPC_VSX_API_SUPPORTED */
      73  #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
      74           {
      75              static volatile sig_atomic_t no_vsx = -1; /* not checked */
      76  
      77              if (no_vsx < 0)
      78                 no_vsx = !png_have_vsx(pp);
      79  
      80              if (no_vsx)
      81                 return;
      82           }
      83  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
      84           break;
      85  #endif
      86  #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
      87  
      88  #ifdef PNG_POWERPC_VSX_API_SUPPORTED
      89        default: /* OFF or INVALID */
      90           return;
      91  
      92        case PNG_OPTION_ON:
      93           /* Option turned on */
      94           break;
      95     }
      96  #endif
      97  
      98     /* IMPORTANT: any new internal functions used here must be declared using
      99      * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
     100      * 'prefix' option to configure works:
     101      *
     102      *    ./configure --with-libpng-prefix=foobar_
     103      *
     104      * Verify you have got this right by running the above command, doing a build
     105      * and examining pngprefix.h; it must contain a #define for every external
     106      * function you add.  (Notice that this happens automatically for the
     107      * initialization function.)
     108      */
     109     pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
     110  
     111     if (bpp == 3)
     112     {
     113        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
     114        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
     115        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
     116     }
     117  
     118     else if (bpp == 4)
     119     {
     120        pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
     121        pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
     122        pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
     123     }
     124  }
     125  #endif /* PNG_POWERPC_VSX_OPT > 0 */
     126  #endif /* READ */