1
2 /* powerpc_init.c - POWERPC optimised filter functions
3 *
4 * Copyright (c) 2018 Cosmin Truta
5 * Copyright (c) 2017 Glenn Randers-Pehrson
6 * Written by Vadim Barkov, 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
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_POWERPC_VSX_OPT > 0
24 #ifdef PNG_POWERPC_VSX_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 PowerPC
27 * VSX 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_POWERPC_VSX_FILE to the file name of file containing
32 * a fragment of C source code which defines the png_have_vsx function. There
33 * are a number of implementations in contrib/powerpc-vsx, but the only one that
34 * has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
35 * implementation which reads /proc/cpufino.
36 */
37 #ifndef PNG_POWERPC_VSX_FILE
38 # ifdef __linux__
39 # define PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
40 # endif
41 #endif
42
43 #ifdef PNG_POWERPC_VSX_FILE
44
45 #include <signal.h> /* for sig_atomic_t */
46 static int png_have_vsx(png_structp png_ptr);
47 #include PNG_POWERPC_VSX_FILE
48
49 #else /* PNG_POWERPC_VSX_FILE */
50 # error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
51 #endif /* PNG_POWERPC_VSX_FILE */
52 #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
53
54 void
png_init_filter_functions_vsx(png_structp pp,unsigned int bpp)55 png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
56 {
57 /* The switch statement is compiled in for POWERPC_VSX_API, the call to
58 * png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
59 * the check is only performed if the API has not set the PowerPC option on
60 * or off explicitly. In this case the check controls what happens.
61 */
62
63 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
64 switch ((pp->options >> PNG_POWERPC_VSX) & 3)
65 {
66 case PNG_OPTION_UNSET:
67 /* Allow the run-time check to execute if it has been enabled -
68 * thus both API and CHECK can be turned on. If it isn't supported
69 * this case will fall through to the 'default' below, which just
70 * returns.
71 */
72 #endif /* PNG_POWERPC_VSX_API_SUPPORTED */
73 #ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
74 {
75 static volatile sig_atomic_t no_vsx = -1; /* not checked */
76
77 if (no_vsx < 0)
78 no_vsx = !png_have_vsx(pp);
79
80 if (no_vsx)
81 return;
82 }
83 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
84 break;
85 #endif
86 #endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
87
88 #ifdef PNG_POWERPC_VSX_API_SUPPORTED
89 default: /* OFF or INVALID */
90 return;
91
92 case PNG_OPTION_ON:
93 /* Option turned on */
94 break;
95 }
96 #endif
97
98 /* IMPORTANT: any new internal functions used here must be declared using
99 * PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
100 * 'prefix' option to configure works:
101 *
102 * ./configure --with-libpng-prefix=foobar_
103 *
104 * Verify you have got this right by running the above command, doing a build
105 * and examining pngprefix.h; it must contain a #define for every external
106 * function you add. (Notice that this happens automatically for the
107 * initialization function.)
108 */
109 pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
110
111 if (bpp == 3)
112 {
113 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
114 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
115 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
116 }
117
118 else if (bpp == 4)
119 {
120 pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
121 pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
122 pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
123 }
124 }
125 #endif /* PNG_POWERPC_VSX_OPT > 0 */
126 #endif /* READ */
127