libpng/arm/arm_init.c
John Bowler 6cf32b460f [libpng16] Rearranged the ARM-NEON optimizations: Isolated the machine specific
code to the hardware subdirectory and added comments to pngrutil.c so that
implementors of other optimizations know what to do.
2012-12-15 07:55:54 -06:00

87 lines
2.3 KiB
C

/* arm_init.c - NEON optimised filter functions
*
* Copyright (c) 2012 Glenn Randers-Pehrson
* Written by Mans Rullgard, 2011.
* Last changed in libpng 1.5.14 [(PENDING RELEASE)]
*
* This code is released under the libpng license.
* For conditions of distribution and use, see the disclaimer
* and license in png.h
*/
#include "../pngpriv.h"
/* __arm__ is defined by GCC, MSVC defines _M_ARM to the ARM version number */
#if defined __linux__ && defined __arm__
#include <stdio.h>
#include <elf.h>
#include <asm/hwcap.h>
static int png_have_hwcap(unsigned cap)
{
FILE *f = fopen("/proc/self/auxv", "r");
Elf32_auxv_t aux;
int have_cap = 0;
if (!f)
return 0;
while (fread(&aux, sizeof(aux), 1, f) > 0)
{
if (aux.a_type == AT_HWCAP &&
aux.a_un.a_val & cap)
{
have_cap = 1;
break;
}
}
fclose(f);
return have_cap;
}
#endif /* __linux__ && __arm__ */
void
png_init_filter_functions_neon(png_structp pp, unsigned int bpp)
{
#ifdef __arm__
#ifdef __linux__
if (!png_have_hwcap(HWCAP_NEON))
return;
#endif
/* IMPORTANT: any new external functions used here must be declared using
* PNG_INTERNAL_FUNCTION in ../pngpriv.h. This is required so that the
* 'prefix' option to configure works:
*
* ./configure --with-libpng-prefix=foobar_
*
* Verify you have got this right by running the above command, doing a build
* and examining pngprefix.h; it must contain a #define for every external
* function you add. (Notice that this happens automatically for the
* initialization function.)
*/
pp->read_filter[PNG_FILTER_VALUE_UP-1] = png_read_filter_row_up_neon;
if (bpp == 3)
{
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_neon;
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_neon;
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
png_read_filter_row_paeth3_neon;
}
else if (bpp == 4)
{
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_neon;
pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_neon;
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
png_read_filter_row_paeth4_neon;
}
#else
PNG_UNUSED(pp)
PNG_UNUSED(bpp)
#endif
}