1
  2/* mips_init.c - MSA optimised filter functions
  3 *
  4 * Copyright (c) 2016 Glenn Randers-Pehrson
  5 * Written by Mandar Sahastrabuddhe, 2016.
  6 * Last changed in libpng 1.6.25 [September 1, 2016]
  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_MIPS_MSA_OPT > 0
 23#ifdef PNG_MIPS_MSA_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 MIPS
 26 * MSA 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_MIPS_MSA_FILE to the file name of file containing
 31 * a fragment of C source code which defines the png_have_msa function.  There
 32 * are a number of implementations in contrib/mips-msa, but the only one that
 33 * has partial support is contrib/mips-msa/linux.c - a generic Linux
 34 * implementation which reads /proc/cpufino.
 35 */
 36#ifndef PNG_MIPS_MSA_FILE
 37#  ifdef __linux__
 38#     define PNG_MIPS_MSA_FILE "contrib/mips-msa/linux.c"
 39#  endif
 40#endif
 41
 42#ifdef PNG_MIPS_MSA_FILE
 43
 44#include <signal.h> /* for sig_atomic_t */
 45static int png_have_msa(png_structp png_ptr);
 46#include PNG_MIPS_MSA_FILE
 47
 48#else  /* PNG_MIPS_MSA_FILE */
 49#  error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
 50#endif /* PNG_MIPS_MSA_FILE */
 51#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
 52
 53#ifndef PNG_ALIGNED_MEMORY_SUPPORTED
 54#  error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
 55#endif
 56
 57void
 58png_init_filter_functions_msa(png_structp pp, unsigned int bpp)
 59{
 60   /* The switch statement is compiled in for MIPS_MSA_API, the call to
 61    * png_have_msa is compiled in for MIPS_MSA_CHECK. If both are defined
 62    * the check is only performed if the API has not set the MSA option on
 63    * or off explicitly. In this case the check controls what happens.
 64    */
 65
 66#ifdef PNG_MIPS_MSA_API_SUPPORTED
 67   switch ((pp->options >> PNG_MIPS_MSA) & 3)
 68   {
 69      case PNG_OPTION_UNSET:
 70         /* Allow the run-time check to execute if it has been enabled -
 71          * thus both API and CHECK can be turned on.  If it isn't supported
 72          * this case will fall through to the 'default' below, which just
 73          * returns.
 74          */
 75#endif /* PNG_MIPS_MSA_API_SUPPORTED */
 76#ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
 77         {
 78            static volatile sig_atomic_t no_msa = -1; /* not checked */
 79
 80            if (no_msa < 0)
 81               no_msa = !png_have_msa(pp);
 82
 83            if (no_msa)
 84               return;
 85         }
 86#ifdef PNG_MIPS_MSA_API_SUPPORTED
 87         break;
 88#endif
 89#endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
 90
 91#ifdef PNG_MIPS_MSA_API_SUPPORTED
 92      default: /* OFF or INVALID */
 93         return;
 94
 95      case PNG_OPTION_ON:
 96         /* Option turned on */
 97         break;
 98   }
 99#endif
100
101   /* IMPORTANT: any new external functions used here must be declared using
102    * PNG_INTERNAL_FUNCTION in ../pngpriv.h.  This is required so that the
103    * 'prefix' option to configure works:
104    *
105    *    ./configure --with-libpng-prefix=foobar_
106    *
107    * Verify you have got this right by running the above command, doing a build
108    * and examining pngprefix.h; it must contain a #define for every external
109    * function you add.  (Notice that this happens automatically for the
110    * initialization function.)
111    */
112   pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_msa;
113
114   if (bpp == 3)
115   {
116      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_msa;
117      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_msa;
118      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_msa;
119   }
120
121   else if (bpp == 4)
122   {
123      pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_msa;
124      pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_msa;
125      pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_msa;
126   }
127}
128#endif /* PNG_MIPS_MSA_OPT > 0 */
129#endif /* READ */