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[libpng16] Rearranged the ARM-NEON optimizations: Isolated the machine specific

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code to the hardware subdirectory and added comments to pngrutil.c so that
implementors of other optimizations know what to do.
This commit is contained in:
John Bowler
2012-12-13 11:26:50 -06:00
committed by Glenn Randers-Pehrson
parent 5c2d76fdef
commit f758d6c813
8 changed files with 111 additions and 68 deletions
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72
pngrutil.c
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@@ -3863,66 +3863,6 @@ png_read_filter_row_paeth_multibyte_pixel(png_row_infop row_info, png_bytep row,
}
}
#ifdef PNG_ARM_NEON
#ifdef __linux__
#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__ */
static void
png_init_filter_functions_neon(png_structrp pp, unsigned int bpp)
{
#ifdef __linux__
if (!png_have_hwcap(HWCAP_NEON))
return;
#endif
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;
}
}
#endif /* PNG_ARM_NEON */
static void
png_init_filter_functions(png_structrp pp)
{
@@ -3938,8 +3878,16 @@ png_init_filter_functions(png_structrp pp)
pp->read_filter[PNG_FILTER_VALUE_PAETH-1] =
png_read_filter_row_paeth_multibyte_pixel;
#ifdef PNG_ARM_NEON
png_init_filter_functions_neon(pp, bpp);
#ifdef PNG_FILTER_OPTIMIZATIONS
/* To use this define PNG_FILTER_OPTIMIZATIONS as the name of a function to
* call to install hardware optimizations for the above functions; simply
* replace whatever elements of the pp->read_filter[] array with a hardware
* specific (or, for that matter, generic) optimization.
*
* To see an example of this examine what configure.ac does when
* --enable-arm-neon is specified on the command line.
*/
PNG_FILTER_OPTIMIZATIONS(pp, bpp);
#endif
}