external/libpng-1.6.37/powerpc/powerpc_init.c

   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 */