1
2 /* powerpc_init.c - POWERPC optimised filter functions
3 *
4 * Copyright (c) 2017 Glenn Randers-Pehrson
5 * Written by Vadim Barkov, 2017.
6 * Last changed in libpng 1.6.29 [March 16, 2017]
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_POWERPC_VSX_OPT > 0
23 #ifdef PNG_POWERPC_VSX_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 PowerPC
26 * VSX 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_POWERPC_VSX_FILE to the file name of file containing
31 * a fragment of C source code which defines the png_have_vsx function. There
32 * are a number of implementations in contrib/powerpc-vsx, but the only one that
33 * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
34 * implementation which reads /proc/cpufino.
35 */
36 #ifndef PNG_POWERPC_VSX_FILE
37 # ifdef __linux__
38 # define PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
39 # endif
40 #endif
41
42 #ifdef PNG_POWERPC_VSX_FILE
43
44 #include <signal.h> /* for sig_atomic_t */
45 static int png_have_vsx(png_structp png_ptr);
46 #include PNG_POWERPC_VSX_FILE
47
48 #else /* PNG_POWERPC_VSX_FILE */
49 # error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
50 #endif /* PNG_POWERPC_VSX_FILE */
51 #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
52
53 void
png_init_filter_functions_vsx(png_structp pp,unsigned int bpp)54 png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
55 {
56 /* The switch statement is compiled in for POWERPC_VSX_API, the call to
57 * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
58 * the check is only performed if the API has not set the PowerPC option on
59 * or off explicitly. In this case the check controls what happens.
60 */
61
62 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
63 switch ((pp->options >> PNG_POWERPC_VSX) & 3)
64 {
65 case PNG_OPTION_UNSET:
66 /* Allow the run-time check to execute if it has been enabled -
67 * thus both API and CHECK can be turned on. If it isn't supported
68 * this case will fall through to the 'default' below, which just
69 * returns.
70 */
71 #endif /* PNG_POWERPC_VSX_API_SUPPORTED */
72 #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
73 {
74 static volatile sig_atomic_t no_vsx = -1; /* not checked */
75
76 if (no_vsx < 0)
77 no_vsx = !png_have_vsx(pp);
78
79 if (no_vsx)
80 return;
81 }
82 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
83 break;
84 #endif
85 #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
86
87 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
88 default: /* OFF or INVALID */
89 return;
90
91 case PNG_OPTION_ON:
92 /* Option turned on */
93 break;
94 }
95 #endif
96
97 /* IMPORTANT: any new internal functions used here must be declared using
98 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
99 * 'prefix' option to configure works:
100 *
101 * ./configure --with-libpng-prefix=foobar_
102 *
103 * Verify you have got this right by running the above command, doing a build
104 * and examining pngprefix.h; it must contain a #define for every external
105 * function you add. (Notice that this happens automatically for the
106 * initialization function.)
107 */
108 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
109
110 if (bpp == 3)
111 {
112 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
113 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
114 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
115 }
116
117 else if (bpp == 4)
118 {
119 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
120 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
121 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
122 }
123 }
124 #endif /* PNG_POWERPC_VSX_OPT > 0 */
125 #endif /* READ */
126