summaryrefslogtreecommitdiff
path: root/arm/arm_init.c
blob: d87b6e727b5ddc4c3c94f75d002917e0d2c5fbf6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134

/* arm_init.c - NEON optimised filter functions
 *
 * Copyright (c) 2014 Glenn Randers-Pehrson
 * Written by Mans Rullgard, 2011.
 * Last changed in libpng 1.6.16 [(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 /* READ */