126 lines
4.2 KiB
C
126 lines
4.2 KiB
C
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/* powerpc_init.c - POWERPC optimised filter functions
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*
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* Copyright (c) 2017 Glenn Randers-Pehrson
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* Written by Vadim Barkov, 2017.
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* Last changed in libpng 1.6.29 [March 16, 2017]
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*
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* This code is released under the libpng license.
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* For conditions of distribution and use, see the disclaimer
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* and license in png.h
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*/
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/* Below, after checking __linux__, various non-C90 POSIX 1003.1 functions are
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* called.
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*/
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#define _POSIX_SOURCE 1
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#include <stdio.h>
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#include "../pngpriv.h"
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#ifdef PNG_READ_SUPPORTED
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#if PNG_POWERPC_VSX_OPT > 0
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#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED /* Do run-time checks */
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/* WARNING: it is strongly recommended that you do not build libpng with
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* run-time checks for CPU features if at all possible. In the case of the PowerPC
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* VSX instructions there is no processor-specific way of detecting the
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* presence of the required support, therefore run-time detection is extremely
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* OS specific.
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*
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* You may set the macro PNG_POWERPC_VSX_FILE to the file name of file containing
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* a fragment of C source code which defines the png_have_vsx function. There
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* are a number of implementations in contrib/powerpc-vsx, but the only one that
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* has partial support is contrib/powerpc-vsx/linux.c - a generic Linux
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* implementation which reads /proc/cpufino.
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*/
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#ifndef PNG_POWERPC_VSX_FILE
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# ifdef __linux__
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# define PNG_POWERPC_VSX_FILE "contrib/powerpc-vsx/linux_aux.c"
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# endif
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#endif
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#ifdef PNG_POWERPC_VSX_FILE
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#include <signal.h> /* for sig_atomic_t */
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static int png_have_vsx(png_structp png_ptr);
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#include PNG_POWERPC_VSX_FILE
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#else /* PNG_POWERPC_VSX_FILE */
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# error "PNG_POWERPC_VSX_FILE undefined: no support for run-time POWERPC VSX checks"
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#endif /* PNG_POWERPC_VSX_FILE */
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#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
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void
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png_init_filter_functions_vsx(png_structp pp, unsigned int bpp)
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{
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/* The switch statement is compiled in for POWERPC_VSX_API, the call to
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* png_have_vsx is compiled in for POWERPC_VSX_CHECK. If both are defined
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* the check is only performed if the API has not set the PowerPC option on
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* or off explicitly. In this case the check controls what happens.
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*/
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#ifdef PNG_POWERPC_VSX_API_SUPPORTED
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switch ((pp->options >> PNG_POWERPC_VSX) & 3)
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{
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case PNG_OPTION_UNSET:
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/* Allow the run-time check to execute if it has been enabled -
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* thus both API and CHECK can be turned on. If it isn't supported
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* this case will fall through to the 'default' below, which just
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* returns.
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*/
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#endif /* PNG_POWERPC_VSX_API_SUPPORTED */
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#ifdef PNG_POWERPC_VSX_CHECK_SUPPORTED
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{
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static volatile sig_atomic_t no_vsx = -1; /* not checked */
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if (no_vsx < 0)
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no_vsx = !png_have_vsx(pp);
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if (no_vsx)
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return;
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}
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#ifdef PNG_POWERPC_VSX_API_SUPPORTED
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break;
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#endif
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#endif /* PNG_POWERPC_VSX_CHECK_SUPPORTED */
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#ifdef PNG_POWERPC_VSX_API_SUPPORTED
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default: /* OFF or INVALID */
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return;
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case PNG_OPTION_ON:
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/* Option turned on */
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break;
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}
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#endif
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/* IMPORTANT: any new internal functions used here must be declared using
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* PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
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* 'prefix' option to configure works:
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*
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* ./configure --with-libpng-prefix=foobar_
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*
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* Verify you have got this right by running the above command, doing a build
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* and examining pngprefix.h; it must contain a #define for every external
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* function you add. (Notice that this happens automatically for the
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* initialization function.)
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*/
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pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_vsx;
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if (bpp == 3)
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{
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pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_vsx;
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pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_vsx;
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pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth3_vsx;
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}
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else if (bpp == 4)
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{
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pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_vsx;
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pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_vsx;
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pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = png_read_filter_row_paeth4_vsx;
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}
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}
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#endif /* PNG_POWERPC_VSX_OPT > 0 */
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#endif /* READ */
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