1
  2/* powerpc_init.c - POWERPC optimised filter functions
  3 *
  4 * Copyright (c) 2017 Glenn Randers-Pehrson
  5 * Written by Vadim Barkov, 2017.
  6 * Last changed in libpng 1.6.29 [March 16, 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/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
 13 * called.
 14 */
 15#define _POSIX_SOURCE 1
 16
 17#include <stdio.h>
 18#include "../pngpriv.h"
 19
 20#ifdef PNG_READ_SUPPORTED
 21
 22#if PNG_POWERPC_VSX_OPT > 0
 23#ifdef PNG_POWERPC_VSX_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 PowerPC
 26 * VSX 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_POWERPC_VSX_FILE to the file name of file containing
 31 * a fragment of C source code which defines the png_have_vsx function.  There
 32 * are a number of implementations in contrib/powerpc-vsx, but the only one that
 33 * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
 34 * implementation which reads /proc/cpufino.
 35 */
 36#ifndef PNG_POWERPC_VSX_FILE
 37#  ifdef __linux__
 38#     define  PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
 39#  endif
 40#endif
 41
 42#ifdef PNG_POWERPC_VSX_FILE
 43
 44#include <signal.h> /* for sig_atomic_t */
 45static int png_have_vsx(png_structp png_ptr);
 46#include PNG_POWERPC_VSX_FILE
 47
 48#else  /* PNG_POWERPC_VSX_FILE */
 49#  error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
 50#endif /* PNG_POWERPC_VSX_FILE */
 51#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
 52
 53void
 54png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
 55{
 56   /* The switch statement is compiled in for POWERPC_VSX_API, the call to
 57    * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
 58    * the check is only performed if the API has not set the PowerPC option on
 59    * or off explicitly. In this case the check controls what happens.
 60    */
 61
 62#ifdef PNG_POWERPC_VSX_API_SUPPORTED
 63   switch ((pp->options >> PNG_POWERPC_VSX) & 3)
 64   {
 65      case PNG_OPTION_UNSET:
 66         /* Allow the run-time check to execute if it has been enabled -
 67          * thus both API and CHECK can be turned on.  If it isn't supported
 68          * this case will fall through to the 'default' below, which just
 69          * returns.
 70          */
 71#endif /* PNG_POWERPC_VSX_API_SUPPORTED */
 72#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
 73         {
 74            static volatile sig_atomic_t no_vsx = -1; /* not checked */
 75
 76            if (no_vsx < 0)
 77               no_vsx = !png_have_vsx(pp);
 78
 79            if (no_vsx)
 80               return;
 81         }
 82#ifdef PNG_POWERPC_VSX_API_SUPPORTED
 83         break;
 84#endif
 85#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
 86
 87#ifdef PNG_POWERPC_VSX_API_SUPPORTED
 88      default: /* OFF or INVALID */
 89         return;
 90
 91      case PNG_OPTION_ON:
 92         /* Option turned on */
 93         break;
 94   }
 95#endif
 96
 97   /* IMPORTANT: any new internal functions used here must be declared using
 98    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
 99    * 'prefix' option to configure works:
100    *
101    *    ./configure --with-libpng-prefix=foobar_
102    *
103    * Verify you have got this right by running the above command, doing a build
104    * and examining pngprefix.h; it must contain a #define for every external
105    * function you add.  (Notice that this happens automatically for the
106    * initialization function.)
107    */
108   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
109
110   if (bpp == 3)
111   {
112      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
113      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
114      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
115   }
116
117   else if (bpp == 4)
118   {
119      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
120      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
121      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
122   }
123}
124#endif /* PNG_POWERPC_VSX_OPT > 0 */
125#endif /* READ */