1 2 /* arm_init.c - NEON optimised filter functions 3 * 4 * Copyright (c) 2014 Glenn Randers-Pehrson 5 * Written by Mans Rullgard, 2011. 6 * Last changed in libpng 1.6.10 [March 6, 2014] 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 #if PNG_ARM_NEON_OPT > 0 21 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED /* Do run-time checks */ 22 /* WARNING: it is strongly recommended that you do not build libpng with 23 * run-time checks for CPU features if at all possible. In the case of the ARM 24 * NEON instructions there is no processor-specific way of detecting the 25 * presense of the required support, therefore run-time detectioon is extremely 26 * OS specific. 27 * 28 * You may set the macro PNG_ARM_NEON_FILE to the file name of file containing 29 * a fragment of C source code which defines the png_have_neon function. There 30 * are a number of implementations in contrib/arm-neon, but the only one that 31 * has partial support is contrib/arm-neon/linux.c - a generic Linux 32 * implementation which reads /proc/cpufino. 33 */ 34 #ifndef PNG_ARM_NEON_FILE 35 # ifdef __linux__ 36 # define PNG_ARM_NEON_FILE "contrib/arm-neon/linux.c" 37 # endif 38 #endif 39 40 #ifdef PNG_ARM_NEON_FILE 41 42 #include <signal.h> /* for sig_atomic_t */ 43 static int png_have_neon(png_structp png_ptr); 44 #include PNG_ARM_NEON_FILE 45 46 #else /* PNG_ARM_NEON_FILE */ 47 # error "PNG_ARM_NEON_FILE undefined: no support for run-time ARM NEON checks" 48 #endif /* PNG_ARM_NEON_FILE */ 49 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ 50 51 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED 52 # error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED" 53 #endif 54 55 void 56 png_init_filter_functions_neon(png_structp pp, unsigned int bpp) 57 { 58 /* The switch statement is compiled in for ARM_NEON_API, the call to 59 * png_have_neon is compiled in for ARM_NEON_CHECK. If both are defined 60 * the check is only performed if the API has not set the NEON option on 61 * or off explicitly. In this case the check controls what happens. 62 * 63 * If the CHECK is not compiled in and the option is UNSET the behavior prior 64 * to 1.6.7 was to use the NEON code - this was a bug caused by having the 65 * wrong order of the 'ON' and 'default' cases. UNSET now defaults to OFF, 66 * as documented in png.h 67 */ 68 #ifdef PNG_ARM_NEON_API_SUPPORTED 69 switch ((pp->options >> PNG_ARM_NEON) & 3) 70 { 71 case PNG_OPTION_UNSET: 72 /* Allow the run-time check to execute if it has been enabled - 73 * thus both API and CHECK can be turned on. If it isn't supported 74 * this case will fall through to the 'default' below, which just 75 * returns. 76 */ 77 #endif /* PNG_ARM_NEON_API_SUPPORTED */ 78 #ifdef PNG_ARM_NEON_CHECK_SUPPORTED 79 { 80 static volatile sig_atomic_t no_neon = -1; /* not checked */ 81 82 if (no_neon < 0) 83 no_neon = !png_have_neon(pp); 84 85 if (no_neon) 86 return; 87 } 88 #ifdef PNG_ARM_NEON_API_SUPPORTED 89 break; 90 #endif 91 #endif /* PNG_ARM_NEON_CHECK_SUPPORTED */ 92 93 #ifdef PNG_ARM_NEON_API_SUPPORTED 94 default: /* OFF or INVALID */ 95 return; 96 97 case PNG_OPTION_ON: 98 /* Option turned on */ 99 break; 100 } 101 #endif 102 103 /* IMPORTANT: any new external functions used here must be declared using 104 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the 105 * 'prefix' option to configure works: 106 * 107 * ./configure --with-libpng-prefix=foobar_ 108 * 109 * Verify you have got this right by running the above command, doing a build 110 * and examining pngprefix.h; it must contain a #define for every external 111 * function you add. (Notice that this happens automatically for the 112 * initialization function.) 113 */ 114 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon; 115 116 if (bpp == 3) 117 { 118 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon; 119 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon; 120 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 121 png_read_filter_row_paeth3_neon; 122 } 123 124 else if (bpp == 4) 125 { 126 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon; 127 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon; 128 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = 129 png_read_filter_row_paeth4_neon; 130 } 131 } 132 #endif /* PNG_ARM_NEON_OPT > 0 */ 133 #endif /* PNG_READ_SUPPORTED */ 134
