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| 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 */ |
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