| |
| /* arm_init.c - NEON optimised filter functions |
| * |
| * Copyright (c) 2014 Glenn Randers-Pehrson |
| * Written by Mans Rullgard, 2011. |
| * Last changed in libpng 1.6.10 [(PENDING RELEASE)] |
| * |
| * 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 "../pngpriv.h" |
| |
| #ifdef PNG_READ_SUPPORTED |
| #if PNG_ARM_NEON_OPT > 0 |
| #ifdef PNG_ARM_NEON_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 ARM |
| * NEON 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_ARM_NEON_FILE to the file name of file containing |
| * a fragment of C source code which defines the png_have_neon function. There |
| * are a number of implementations in contrib/arm-neon, but the only one that |
| * has partial support is contrib/arm-neon/linux.c - a generic Linux |
| * implementation which reads /proc/cpufino. |
| */ |
| #ifndef PNG_ARM_NEON_FILE |
| # ifdef __linux__ |
| # define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c" |
| # endif |
| #endif |
| |
| #ifdef PNG_ARM_NEON_FILE |
| |
| #include <signal.h> /* for sig_atomic_t */ |
| static int png_have_neon(png_structp png_ptr); |
| #include PNG_ARM_NEON_FILE |
| |
| #else /* PNG_ARM_NEON_FILE */ |
| # error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks" |
| #endif /* PNG_ARM_NEON_FILE */ |
| #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ |
| |
| #ifndef PNG_ALIGNED_MEMORY_SUPPORTED |
| # error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED" |
| #endif |
| |
| void |
| png_init_filter_functions_neon(png_structp pp, unsigned int bpp) |
| { |
| /* The switch statement is compiled in for ARM_NEON_API, the call to |
| * png_have_neon is compiled in for ARM_NEON_CHECK. If both are defined |
| * the check is only performed if the API has not set the NEON option on |
| * or off explicitly. In this case the check controls what happens. |
| * |
| * If the CHECK is not compiled in and the option is UNSET the behavior prior |
| * to 1.6.7 was to use the NEON code - this was a bug caused by having the |
| * wrong order of the 'ON' and 'default' cases. UNSET now defaults to OFF, |
| * as documented in png.h |
| */ |
| #ifdef PNG_ARM_NEON_API_SUPPORTED |
| switch ((pp->options >> PNG_ARM_NEON) & 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_ARM_NEON_API_SUPPORTED */ |
| #ifdef PNG_ARM_NEON_CHECK_SUPPORTED |
| { |
| static volatile sig_atomic_t no_neon = -1; /* not checked */ |
| |
| if (no_neon < 0) |
| no_neon = !png_have_neon(pp); |
| |
| if (no_neon) |
| return; |
| } |
| #ifdef PNG_ARM_NEON_API_SUPPORTED |
| break; |
| #endif |
| #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ |
| |
| #ifdef PNG_ARM_NEON_API_SUPPORTED |
| default: /* OFF or INVALID */ |
| return; |
| |
| case PNG_OPTION_ON: |
| /* Option turned on */ |
| break; |
| } |
| #endif |
| |
| /* IMPORTANT: any new external 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_neon; |
| |
| if (bpp == 3) |
| { |
| pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon; |
| pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon; |
| pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = |
| png_read_filter_row_paeth3_neon; |
| } |
| |
| else if (bpp == 4) |
| { |
| pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon; |
| pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon; |
| pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = |
| png_read_filter_row_paeth4_neon; |
| } |
| } |
| #endif /* PNG_ARM_NEON_OPT > 0 */ |
| #endif /* PNG_READ_SUPPORTED */ |