1
2 /* mips_init.c - MSA optimised filter functions
3 *
4 * Copyright (c) 2018 Cosmin Truta
5 * Copyright (c) 2016 Glenn Randers-Pehrson
6 * Written by Mandar Sahastrabuddhe, 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
13 /* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
14 * called.
15 */
16 #define _POSIX_SOURCE 1
17
18 #include <stdio.h>
19 #include "../pngpriv.h"
20
21 #ifdef PNG_READ_SUPPORTED
22
23 #if PNG_MIPS_MSA_OPT > 0
24 #ifdef PNG_MIPS_MSA_CHECK_SUPPORTED /* Do run-time checks */
25 /* WARNING: it is strongly recommended that you do not build libpng with
26 * run-time checks for CPU features if at all possible. In the case of the MIPS
27 * MSA instructions there is no processor-specific way of detecting the
28 * presence of the required support, therefore run-time detection is extremely
29 * OS specific.
30 *
31 * You may set the macro PNG_MIPS_MSA_FILE to the file name of file containing
32 * a fragment of C source code which defines the png_have_msa function. There
33 * are a number of implementations in contrib/mips-msa, but the only one that
34 * has partial support is contrib/mips-msa/linux.c - a generic Linux
35 * implementation which reads /proc/cpufino.
36 */
37 #ifndef PNG_MIPS_MSA_FILE
38 # ifdef __linux__
39 # define PNG_MIPS_MSA_FILE "contrib/mips-msa/linux.c"
40 # endif
41 #endif
42
43 #ifdef PNG_MIPS_MSA_FILE
44
45 #include <signal.h> /* for sig_atomic_t */
46 static int png_have_msa(png_structp png_ptr);
47 #include PNG_MIPS_MSA_FILE
48
49 #else /* PNG_MIPS_MSA_FILE */
50 # error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
51 #endif /* PNG_MIPS_MSA_FILE */
52 #endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
53
54 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
55 # error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
56 #endif
57
58 void
59 png_init_filter_functions_msa(png_structp pp, unsigned int bpp)
60 {
61 /* The switch statement is compiled in for MIPS_MSA_API, the call to
62 * png_have_msa is compiled in for MIPS_MSA_CHECK. If both are defined
63 * the check is only performed if the API has not set the MSA option on
64 * or off explicitly. In this case the check controls what happens.
65 */
66
67 #ifdef PNG_MIPS_MSA_API_SUPPORTED
68 switch ((pp->options >> PNG_MIPS_MSA) & 3)
69 {
70 case PNG_OPTION_UNSET:
71 /* Allow the run-time check to execute if it has been enabled -
72 * thus both API and CHECK can be turned on. If it isn't supported
73 * this case will fall through to the 'default' below, which just
74 * returns.
75 */
76 #endif /* PNG_MIPS_MSA_API_SUPPORTED */
77 #ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
78 {
79 static volatile sig_atomic_t no_msa = -1; /* not checked */
80
81 if (no_msa < 0)
82 no_msa = !png_have_msa(pp);
83
84 if (no_msa)
85 return;
86 }
87 #ifdef PNG_MIPS_MSA_API_SUPPORTED
88 break;
89 #endif
90 #endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
91
92 #ifdef PNG_MIPS_MSA_API_SUPPORTED
93 default: /* OFF or INVALID */
94 return;
95
96 case PNG_OPTION_ON:
97 /* Option turned on */
98 break;
99 }
100 #endif
101
102 /* IMPORTANT: any new external functions used here must be declared using
103 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
104 * 'prefix' option to configure works:
105 *
106 * ./configure --with-libpng-prefix=foobar_
107 *
108 * Verify you have got this right by running the above command, doing a build
109 * and examining pngprefix.h; it must contain a #define for every external
110 * function you add. (Notice that this happens automatically for the
111 * initialization function.)
112 */
113 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_msa;
114
115 if (bpp == 3)
116 {
117 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_msa;
118 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_msa;
119 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_msa;
120 }
121
122 else if (bpp == 4)
123 {
124 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_msa;
125 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_msa;
126 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_msa;
127 }
128 }
129 #endif /* PNG_MIPS_MSA_OPT > 0 */
130 #endif /* READ */