1 2 /* arm_init.c - NEON optimised filter functions 3 * 4 * Copyright (c) 2014,2016 Glenn Randers-Pehrson 5 * Written by Mans Rullgard, 2011. 6 * Last changed in libpng 1.6.22 [May 26, 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 "../pngpriv.h" 18 19 #ifdef PNG_READ_SUPPORTED 20 21 #if PNG_ARM_NEON_OPT > 0 22 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */ 23 /* WARNING: it is strongly recommended that you do not build libpng with 24 * run-time checks for CPU features if at all possible. In the case of the ARM 25 * NEON instructions there is no processor-specific way of detecting the 26 * presence of the required support, therefore run-time detection is extremely 27 * OS specific. 28 * 29 * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing 30 * a fragment of C source code which defines the png_have_neon function. There 31 * are a number of implementations in contrib/arm-neon, but the only one that 32 * has partial support is contrib/arm-neon/linux.c - a generic Linux 33 * implementation which reads /proc/cpufino. 34 */ 35 #ifndef PNG_ARM_NEON_FILE 36 # ifdef __linux__ 37 # define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c" 38 # endif 39 #endif 40 41 #ifdef PNG_ARM_NEON_FILE 42 43 #include <signal.h> /* for sig_atomic_t */ 44 static int png_have_neon(png_structp png_ptr); 45 #include PNG_ARM_NEON_FILE 46 47 #else /* PNG_ARM_NEON_FILE */ 48 # error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks" 49 #endif /* PNG_ARM_NEON_FILE */ 50 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ 51 52 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED 53 # error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED" 54 #endif 55 56 void 57 png_init_filter_functions_neon(png_structp pp, unsigned int bpp) 58 { 59 /* The switch statement is compiled in for ARM_NEON_API, the call to 60 * png_have_neon is compiled in for ARM_NEON_CHECK. If both are defined 61 * the check is only performed if the API has not set the NEON option on 62 * or off explicitly. In this case the check controls what happens. 63 * 64 * If the CHECK is not compiled in and the option is UNSET the behavior prior 65 * to 1.6.7 was to use the NEON code - this was a bug caused by having the 66 * wrong order of the 'ON' and 'default' cases. UNSET now defaults to OFF, 67 * as documented in png.h 68 */ 69 png_debug(1, "in png_init_filter_functions_neon"); 70 #ifdef PNG_ARM_NEON_API_SUPPORTED 71 switch ((pp->options >> PNG_ARM_NEON) & 3) 72 { 73 case PNG_OPTION_UNSET: 74 /* Allow the run-time check to execute if it has been enabled - 75 * thus both API and CHECK can be turned on. If it isn't supported 76 * this case will fall through to the 'default' below, which just 77 * returns. 78 */ 79 #endif /* PNG_ARM_NEON_API_SUPPORTED */ 80 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED 81 { 82 static volatile sig_atomic_t no_neon = -1; /* not checked */ 83 84 if (no_neon < 0) 85 no_neon = !png_have_neon(pp); 86 87 if (no_neon) 88 return; 89 } 90 #ifdef PNG_ARM_NEON_API_SUPPORTED 91 break; 92 #endif 93 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ 94 95 #ifdef PNG_ARM_NEON_API_SUPPORTED 96 default: /* OFF or INVALID */ 97 return; 98 99 case PNG_OPTION_ON: 100 /* Option turned on */ 101 break; 102 } 103 #endif 104 105 /* IMPORTANT: any new external functions used here must be declared using 106 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the 107 * 'prefix' option to configure works: 108 * 109 * ./configure --with-libpng-prefix=foobar_ 110 * 111 * Verify you have got this right by running the above command, doing a build 112 * and examining pngprefix.h; it must contain a #define for every external 113 * function you add. (Notice that this happens automatically for the 114 * initialization function.) 115 */ 116 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon; 117 118 if (bpp == 3) 119 { 120 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon; 121 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon; 122 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 123 png_read_filter_row_paeth3_neon; 124 } 125 126 else if (bpp == 4) 127 { 128 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon; 129 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon; 130 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 131 png_read_filter_row_paeth4_neon; 132 } 133 } 134 #endif /* PNG_ARM_NEON_OPT > 0 */ 135 #endif /* READ */ 136
