1
2 /* mips_init.c - MSA optimised filter functions
3 *
4 * Copyright (c) 2016 Glenn Randers-Pehrson
5 * Written by Mandar Sahastrabuddhe, 2016.
6 * Last changed in libpng 1.6.25 [September 1, 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 <stdio.h>
18 #include "../pngpriv.h"
19
20 #ifdef PNG_READ_SUPPORTED
21
22 #if PNG_MIPS_MSA_OPT > 0
23 #ifdef PNG_MIPS_MSA_CHECK_SUPPORTED /* Do run-time checks */
24 /* WARNING: it is strongly recommended that you do not build libpng with
25 * run-time checks for CPU features if at all possible. In the case of the MIPS
26 * MSA instructions there is no processor-specific way of detecting the
27 * presence of the required support, therefore run-time detection is extremely
28 * OS specific.
29 *
30 * You may set the macro PNG_MIPS_MSA_FILE to the file name of file containing
31 * a fragment of C source code which defines the png_have_msa function. There
32 * are a number of implementations in contrib/mips-msa, but the only one that
33 * has partial support is contrib/mips-msa/linux.c - a generic Linux
34 * implementation which reads /proc/cpufino.
35 */
36 #ifndef PNG_MIPS_MSA_FILE
37 # ifdef __linux__
38 # define PNG_MIPS_MSA_FILE "contrib/mips-msa/linux.c"
39 # endif
40 #endif
41
42 #ifdef PNG_MIPS_MSA_FILE
43
44 #include <signal.h> /* for sig_atomic_t */
45 static int png_have_msa(png_structp png_ptr);
46 #include PNG_MIPS_MSA_FILE
47
48 #else /* PNG_MIPS_MSA_FILE */
49 # error "PNG_MIPS_MSA_FILE undefined: no support for run-time MIPS MSA checks"
50 #endif /* PNG_MIPS_MSA_FILE */
51 #endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
52
53 #ifndef PNG_ALIGNED_MEMORY_SUPPORTED
54 # error "ALIGNED_MEMORY is required; set: -DPNG_ALIGNED_MEMORY_SUPPORTED"
55 #endif
56
57 void
png_init_filter_functions_msa(png_structp pp,unsigned int bpp)58 png_init_filter_functions_msa(png_structp pp, unsigned int bpp)
59 {
60 /* The switch statement is compiled in for MIPS_MSA_API, the call to
61 * png_have_msa is compiled in for MIPS_MSA_CHECK. If both are defined
62 * the check is only performed if the API has not set the MSA option on
63 * or off explicitly. In this case the check controls what happens.
64 */
65
66 #ifdef PNG_MIPS_MSA_API_SUPPORTED
67 switch ((pp->options >> PNG_MIPS_MSA) & 3)
68 {
69 case PNG_OPTION_UNSET:
70 /* Allow the run-time check to execute if it has been enabled -
71 * thus both API and CHECK can be turned on. If it isn't supported
72 * this case will fall through to the 'default' below, which just
73 * returns.
74 */
75 #endif /* PNG_MIPS_MSA_API_SUPPORTED */
76 #ifdef PNG_MIPS_MSA_CHECK_SUPPORTED
77 {
78 static volatile sig_atomic_t no_msa = -1; /* not checked */
79
80 if (no_msa < 0)
81 no_msa = !png_have_msa(pp);
82
83 if (no_msa)
84 return;
85 }
86 #ifdef PNG_MIPS_MSA_API_SUPPORTED
87 break;
88 #endif
89 #endif /* PNG_MIPS_MSA_CHECK_SUPPORTED */
90
91 #ifdef PNG_MIPS_MSA_API_SUPPORTED
92 default: /* OFF or INVALID */
93 return;
94
95 case PNG_OPTION_ON:
96 /* Option turned on */
97 break;
98 }
99 #endif
100
101 /* IMPORTANT: any new external functions used here must be declared using
102 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
103 * 'prefix' option to configure works:
104 *
105 * ./configure --with-libpng-prefix=foobar_
106 *
107 * Verify you have got this right by running the above command, doing a build
108 * and examining pngprefix.h; it must contain a #define for every external
109 * function you add. (Notice that this happens automatically for the
110 * initialization function.)
111 */
112 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_msa;
113
114 if (bpp == 3)
115 {
116 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_msa;
117 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_msa;
118 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_msa;
119 }
120
121 else if (bpp == 4)
122 {
123 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_msa;
124 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_msa;
125 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_msa;
126 }
127 }
128 #endif /* PNG_MIPS_MSA_OPT > 0 */
129 #endif /* READ */
130