/* arm_init.c - NEON optimised filter functions * * Copyright (c) 2018 Cosmin Truta * Copyright (c) 2014,2016 Glenn Randers-Pehrson * Written by Mans Rullgard, 2011. * * 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 */ png_debug(1, "in png_init_filter_functions_neon"); #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 /* READ */