mirror of
https://git.code.sf.net/p/libpng/code.git
synced 2025-07-10 18:04:09 +02:00
[libpng16] Fix copyright in sse code, use C-style comments
This commit is contained in:
Glenn Randers-Pehrson
parent
d06d66e899
commit
52846504da
1
ANNOUNCE
1
ANNOUNCE
@ -67,6 +67,7 @@ Version 1.6.22beta03 [February 19, 2016]
|
||||
Updated LICENSE to say files in the contrib directory are not
|
||||
necessarily under the libpng license, and that some makefiles have
|
||||
other copyright owners.
|
||||
Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
|
||||
|
||||
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
|
||||
(subscription required; visit
|
||||
|
||||
1
CHANGES
1
CHANGES
@ -5526,6 +5526,7 @@ Version 1.6.22beta03 [February 19, 2016]
|
||||
Updated LICENSE to say files in the contrib directory are not
|
||||
necessarily under the libpng license, and that some makefiles have
|
||||
other copyright owners.
|
||||
Added INTEL-SSE2 support (Mike Klein and Matt Sarett, Google, Inc.).
|
||||
|
||||
Send comments/corrections/commendations to png-mng-implement at lists.sf.net
|
||||
(subscription required; visit
|
||||
|
||||
@ -1,5 +1,4 @@
|
||||
|
||||
Copyright (c) 2016 Google, Inc.
|
||||
|
||||
To enable SSE support, manually edit configure.ac and Makefile.am, following
|
||||
the instructions in the configure.ac.patch and Makefile.am.patch files.
|
||||
To enable SSE support in libpng, manually edit configure.ac and Makefile.am,
|
||||
following the instructions in the configure.ac.patch and Makefile.am.patch
|
||||
files, then configure with -DPNG_INTEL_SSE in CPPFLAGS.
|
||||
|
||||
@ -1,15 +1,18 @@
|
||||
|
||||
#
|
||||
# Copyright (c) 2016 Google, Inc.
|
||||
# Written by Mike Klein and Matt Sarett
|
||||
# Derived from the ARM supporting code in libpng/Makefile.am, which was
|
||||
# Copyright (c) 2004-2015 Glenn Randers-Pehrson
|
||||
#
|
||||
# Last changed in libpng 1.6.22 [(PENDING RELEASE)]
|
||||
#
|
||||
# This code is released under the libpng license.
|
||||
# For conditions of distribution and use, see the disclaimer
|
||||
# and license in png.h
|
||||
#
|
||||
|
||||
# In order to compile Intel SSE optimizations for libpng, please add
|
||||
# the following code to Makefile.am directly beneath the
|
||||
# "if PNG_ARM_NEON ... endif" statement.
|
||||
# the following code to Makefile.am under HOST SPECIFIC OPTIONS
|
||||
# directly beneath the "if PNG_ARM_NEON ... endif" statement.
|
||||
|
||||
if PNG_INTEL_SSE
|
||||
libpng@PNGLIB_MAJOR@@PNGLIB_MINOR@_la_SOURCES += contrib/intel/intel_init.c\
|
||||
|
||||
@ -1,17 +1,21 @@
|
||||
#
|
||||
# Copyright (c) 2016 Google, Inc.
|
||||
# Written by Mike Klein and Matt Sarett
|
||||
# Derived from the ARM supporting code in libpng/configure.ac, which was
|
||||
# Copyright (c) 2004-2015 Glenn Randers-Pehrson
|
||||
#
|
||||
# Last changed in libpng 1.6.22 [(PENDING RELEASE)]
|
||||
#
|
||||
# This code is released under the libpng license.
|
||||
# For conditions of distribution and use, see the disclaimer
|
||||
# and license in png.h
|
||||
#
|
||||
|
||||
# In order to compile Intel SSE optimizations for libpng, please add
|
||||
# the following code to configure.ac under HOST SPECIFIC OPTIONS
|
||||
# directly beneath the section for ARM.
|
||||
|
||||
# INTEL
|
||||
# ===
|
||||
# =====
|
||||
#
|
||||
# INTEL SSE (SIMD) support.
|
||||
|
||||
|
||||
@ -2,6 +2,9 @@
|
||||
/* filter_sse2_intrinsics.c - SSE2 optimized filter functions
|
||||
*
|
||||
* Copyright (c) 2016 Google, Inc.
|
||||
* Written by Mike Klein and Matt Sarett
|
||||
* Derived from arm/filter_neon_intrinsics.c, which was
|
||||
* Copyright (c) 2014 Glenn Randers-Pehrson
|
||||
*
|
||||
* Last changed in libpng 1.6.22 [(PENDING RELEASE)]
|
||||
*
|
||||
@ -18,12 +21,13 @@
|
||||
|
||||
#include <immintrin.h>
|
||||
|
||||
// Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
|
||||
// They're positioned like this:
|
||||
// prev: c b
|
||||
// row: a d
|
||||
// The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
|
||||
// whichever of a, b, or c is closest to p=a+b-c.
|
||||
/* Functions in this file look at most 3 pixels (a,b,c) to predict the 4th (d).
|
||||
* They're positioned like this:
|
||||
* prev: c b
|
||||
* row: a d
|
||||
* The Sub filter predicts d=a, Avg d=(a+b)/2, and Paeth predicts d to be
|
||||
* whichever of a, b, or c is closest to p=a+b-c.
|
||||
*/
|
||||
|
||||
static __m128i load3(const void* p) {
|
||||
png_uint_32 packed;
|
||||
@ -47,9 +51,10 @@ static void store4(void* p, __m128i v) {
|
||||
void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// The Sub filter predicts each pixel as the previous pixel, a.
|
||||
// There is no pixel to the left of the first pixel. It's encoded directly.
|
||||
// That works with our main loop if we just say that left pixel was zero.
|
||||
/* The Sub filter predicts each pixel as the previous pixel, a.
|
||||
* There is no pixel to the left of the first pixel. It's encoded directly.
|
||||
* That works with our main loop if we just say that left pixel was zero.
|
||||
*/
|
||||
__m128i a, d = _mm_setzero_si128();
|
||||
|
||||
int rb = row_info->rowbytes;
|
||||
@ -66,9 +71,10 @@ void png_read_filter_row_sub3_sse2(png_row_infop row_info, png_bytep row,
|
||||
void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// The Sub filter predicts each pixel as the previous pixel, a.
|
||||
// There is no pixel to the left of the first pixel. It's encoded directly.
|
||||
// That works with our main loop if we just say that left pixel was zero.
|
||||
/* The Sub filter predicts each pixel as the previous pixel, a.
|
||||
* There is no pixel to the left of the first pixel. It's encoded directly.
|
||||
* That works with our main loop if we just say that left pixel was zero.
|
||||
*/
|
||||
__m128i a, d = _mm_setzero_si128();
|
||||
|
||||
int rb = row_info->rowbytes;
|
||||
@ -85,10 +91,11 @@ void png_read_filter_row_sub4_sse2(png_row_infop row_info, png_bytep row,
|
||||
void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// The Avg filter predicts each pixel as the (truncated) average of a and b.
|
||||
// There's no pixel to the left of the first pixel. Luckily, it's
|
||||
// predicted to be half of the pixel above it. So again, this works
|
||||
// perfectly with our loop if we make sure a starts at zero.
|
||||
/* The Avg filter predicts each pixel as the (truncated) average of a and b.
|
||||
* There's no pixel to the left of the first pixel. Luckily, it's
|
||||
* predicted to be half of the pixel above it. So again, this works
|
||||
* perfectly with our loop if we make sure a starts at zero.
|
||||
*/
|
||||
const __m128i zero = _mm_setzero_si128();
|
||||
__m128i b;
|
||||
__m128i a, d = zero;
|
||||
@ -98,9 +105,9 @@ void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
|
||||
b = load3(prev);
|
||||
a = d; d = load3(row );
|
||||
|
||||
// PNG requires a truncating average, so we can't just use _mm_avg_epu8...
|
||||
/* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
|
||||
__m128i avg = _mm_avg_epu8(a,b);
|
||||
// ...but we can fix it up by subtracting off 1 if it rounded up.
|
||||
/* ...but we can fix it up by subtracting off 1 if it rounded up. */
|
||||
avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
|
||||
_mm_set1_epi8(1)));
|
||||
|
||||
@ -116,10 +123,11 @@ void png_read_filter_row_avg3_sse2(png_row_infop row_info, png_bytep row,
|
||||
void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// The Avg filter predicts each pixel as the (truncated) average of a and b.
|
||||
// There's no pixel to the left of the first pixel. Luckily, it's
|
||||
// predicted to be half of the pixel above it. So again, this works
|
||||
// perfectly with our loop if we make sure a starts at zero.
|
||||
/* The Avg filter predicts each pixel as the (truncated) average of a and b.
|
||||
* There's no pixel to the left of the first pixel. Luckily, it's
|
||||
* predicted to be half of the pixel above it. So again, this works
|
||||
* perfectly with our loop if we make sure a starts at zero.
|
||||
*/
|
||||
const __m128i zero = _mm_setzero_si128();
|
||||
__m128i b;
|
||||
__m128i a, d = zero;
|
||||
@ -129,9 +137,9 @@ void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
|
||||
b = load4(prev);
|
||||
a = d; d = load4(row );
|
||||
|
||||
// PNG requires a truncating average, so we can't just use _mm_avg_epu8...
|
||||
/* PNG requires a truncating average, so we can't just use _mm_avg_epu8 */
|
||||
__m128i avg = _mm_avg_epu8(a,b);
|
||||
// ...but we can fix it up by subtracting off 1 if it rounded up.
|
||||
/* ...but we can fix it up by subtracting off 1 if it rounded up. */
|
||||
avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b),
|
||||
_mm_set1_epi8(1)));
|
||||
|
||||
@ -144,25 +152,26 @@ void png_read_filter_row_avg4_sse2(png_row_infop row_info, png_bytep row,
|
||||
}
|
||||
}
|
||||
|
||||
// Returns |x| for 16-bit lanes.
|
||||
/* Returns |x| for 16-bit lanes. */
|
||||
static __m128i abs_i16(__m128i x) {
|
||||
#if PNG_INTEL_SSE_IMPLEMENTATION >= 2
|
||||
return _mm_abs_epi16(x);
|
||||
#else
|
||||
// Read this all as, return x<0 ? -x : x.
|
||||
// To negate two's complement, you flip all the bits then add 1.
|
||||
/* Read this all as, return x<0 ? -x : x.
|
||||
* To negate two's complement, you flip all the bits then add 1.
|
||||
*/
|
||||
__m128i is_negative = _mm_cmplt_epi16(x, _mm_setzero_si128());
|
||||
|
||||
// Flip negative lanes.
|
||||
/* Flip negative lanes. */
|
||||
x = _mm_xor_si128(x, is_negative);
|
||||
|
||||
// +1 to negative lanes, else +0.
|
||||
/* +1 to negative lanes, else +0. */
|
||||
x = _mm_add_epi16(x, _mm_srli_epi16(is_negative, 15));
|
||||
return x;
|
||||
#endif
|
||||
}
|
||||
|
||||
// Bytewise c ? t : e.
|
||||
/* Bytewise c ? t : e. */
|
||||
static __m128i if_then_else(__m128i c, __m128i t, __m128i e) {
|
||||
#if PNG_INTEL_SSE_IMPLEMENTATION >= 3
|
||||
return _mm_blendv_epi8(e,t,c);
|
||||
@ -174,50 +183,52 @@ static __m128i if_then_else(__m128i c, __m128i t, __m128i e) {
|
||||
void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// Paeth tries to predict pixel d using the pixel to the left of it, a,
|
||||
// and two pixels from the previous row, b and c:
|
||||
// prev: c b
|
||||
// row: a d
|
||||
// The Paeth function predicts d to be whichever of a, b, or c is nearest to
|
||||
// p=a+b-c.
|
||||
|
||||
// The first pixel has no left context, and so uses an Up filter, p = b.
|
||||
// This works naturally with our main loop's p = a+b-c if we force a and c
|
||||
// to zero.
|
||||
// Here we zero b and d, which become c and a respectively at the start of
|
||||
// the loop.
|
||||
/* Paeth tries to predict pixel d using the pixel to the left of it, a,
|
||||
* and two pixels from the previous row, b and c:
|
||||
* prev: c b
|
||||
* row: a d
|
||||
* The Paeth function predicts d to be whichever of a, b, or c is nearest to
|
||||
* p=a+b-c.
|
||||
*
|
||||
* The first pixel has no left context, and so uses an Up filter, p = b.
|
||||
* This works naturally with our main loop's p = a+b-c if we force a and c
|
||||
* to zero.
|
||||
* Here we zero b and d, which become c and a respectively at the start of
|
||||
* the loop.
|
||||
*/
|
||||
const __m128i zero = _mm_setzero_si128();
|
||||
__m128i c, b = zero,
|
||||
a, d = zero;
|
||||
|
||||
int rb = row_info->rowbytes;
|
||||
while (rb > 0) {
|
||||
// It's easiest to do this math (particularly, deal with pc) with 16-bit
|
||||
// intermediates.
|
||||
/* It's easiest to do this math (particularly, deal with pc) with 16-bit
|
||||
* intermediates.
|
||||
*/
|
||||
c = b; b = _mm_unpacklo_epi8(load3(prev), zero);
|
||||
a = d; d = _mm_unpacklo_epi8(load3(row ), zero);
|
||||
|
||||
// (p-a) == (a+b-c - a) == (b-c)
|
||||
/* (p-a) == (a+b-c - a) == (b-c) */
|
||||
__m128i pa = _mm_sub_epi16(b,c);
|
||||
|
||||
// (p-b) == (a+b-c - b) == (a-c)
|
||||
/* (p-b) == (a+b-c - b) == (a-c) */
|
||||
__m128i pb = _mm_sub_epi16(a,c);
|
||||
|
||||
// (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c)
|
||||
/* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
|
||||
__m128i pc = _mm_add_epi16(pa,pb);
|
||||
|
||||
pa = abs_i16(pa); // |p-a|
|
||||
pb = abs_i16(pb); // |p-b|
|
||||
pc = abs_i16(pc); // |p-c|
|
||||
pa = abs_i16(pa); /* |p-a| */
|
||||
pb = abs_i16(pb); /* |p-b| */
|
||||
pc = abs_i16(pc); /* |p-c| */
|
||||
|
||||
__m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
|
||||
|
||||
// Paeth breaks ties favoring a over b over c.
|
||||
/* Paeth breaks ties favoring a over b over c. */
|
||||
__m128i nearest = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
|
||||
if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
|
||||
c));
|
||||
|
||||
// Note `_epi8`: we need addition to wrap modulo 255.
|
||||
/* Note `_epi8`: we need addition to wrap modulo 255. */
|
||||
d = _mm_add_epi8(d, nearest);
|
||||
store3(row, _mm_packus_epi16(d,d));
|
||||
|
||||
@ -230,50 +241,52 @@ void png_read_filter_row_paeth3_sse2(png_row_infop row_info, png_bytep row,
|
||||
void png_read_filter_row_paeth4_sse2(png_row_infop row_info, png_bytep row,
|
||||
png_const_bytep prev)
|
||||
{
|
||||
// Paeth tries to predict pixel d using the pixel to the left of it, a,
|
||||
// and two pixels from the previous row, b and c:
|
||||
// prev: c b
|
||||
// row: a d
|
||||
// The Paeth function predicts d to be whichever of a, b, or c is nearest to
|
||||
// p=a+b-c.
|
||||
|
||||
// The first pixel has no left context, and so uses an Up filter, p = b.
|
||||
// This works naturally with our main loop's p = a+b-c if we force a and c
|
||||
// to zero.
|
||||
// Here we zero b and d, which become c and a respectively at the start of
|
||||
// the loop.
|
||||
/* Paeth tries to predict pixel d using the pixel to the left of it, a,
|
||||
* and two pixels from the previous row, b and c:
|
||||
* prev: c b
|
||||
* row: a d
|
||||
* The Paeth function predicts d to be whichever of a, b, or c is nearest to
|
||||
* p=a+b-c.
|
||||
*
|
||||
* The first pixel has no left context, and so uses an Up filter, p = b.
|
||||
* This works naturally with our main loop's p = a+b-c if we force a and c
|
||||
* to zero.
|
||||
* Here we zero b and d, which become c and a respectively at the start of
|
||||
* the loop.
|
||||
*/
|
||||
const __m128i zero = _mm_setzero_si128();
|
||||
__m128i c, b = zero,
|
||||
a, d = zero;
|
||||
|
||||
int rb = row_info->rowbytes;
|
||||
while (rb > 0) {
|
||||
// It's easiest to do this math (particularly, deal with pc) with 16-bit
|
||||
// intermediates.
|
||||
/* It's easiest to do this math (particularly, deal with pc) with 16-bit
|
||||
* intermediates.
|
||||
*/
|
||||
c = b; b = _mm_unpacklo_epi8(load4(prev), zero);
|
||||
a = d; d = _mm_unpacklo_epi8(load4(row ), zero);
|
||||
|
||||
// (p-a) == (a+b-c - a) == (b-c)
|
||||
/* (p-a) == (a+b-c - a) == (b-c) */
|
||||
__m128i pa = _mm_sub_epi16(b,c);
|
||||
|
||||
// (p-b) == (a+b-c - b) == (a-c)
|
||||
/* (p-b) == (a+b-c - b) == (a-c) */
|
||||
__m128i pb = _mm_sub_epi16(a,c);
|
||||
|
||||
// (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c)
|
||||
/* (p-c) == (a+b-c - c) == (a+b-c-c) == (b-c)+(a-c) */
|
||||
__m128i pc = _mm_add_epi16(pa,pb);
|
||||
|
||||
pa = abs_i16(pa); // |p-a|
|
||||
pb = abs_i16(pb); // |p-b|
|
||||
pc = abs_i16(pc); // |p-c|
|
||||
pa = abs_i16(pa); /* |p-a| */
|
||||
pb = abs_i16(pb); /* |p-b| */
|
||||
pc = abs_i16(pc); /* |p-c| */
|
||||
|
||||
__m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb));
|
||||
|
||||
// Paeth breaks ties favoring a over b over c.
|
||||
/* Paeth breaks ties favoring a over b over c. */
|
||||
__m128i nearest = if_then_else(_mm_cmpeq_epi16(smallest, pa), a,
|
||||
if_then_else(_mm_cmpeq_epi16(smallest, pb), b,
|
||||
c));
|
||||
|
||||
// Note `_epi8`: we need addition to wrap modulo 255.
|
||||
/* Note `_epi8`: we need addition to wrap modulo 255. */
|
||||
d = _mm_add_epi8(d, nearest);
|
||||
store4(row, _mm_packus_epi16(d,d));
|
||||
|
||||
|
||||
@ -2,6 +2,9 @@
|
||||
/* intel_init.c - SSE2 optimized filter functions
|
||||
*
|
||||
* Copyright (c) 2016 Google, Inc.
|
||||
* Written by Mike Klein and Matt Sarett
|
||||
* Derived from arm/arm_init.c, which was
|
||||
* Copyright (c) 2014 Glenn Randers-Pehrson
|
||||
*
|
||||
* Last changed in libpng 1.6.22 [(PENDING RELEASE)]
|
||||
*
|
||||
@ -18,13 +21,14 @@
|
||||
void
|
||||
png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
|
||||
{
|
||||
// The techniques used to implement each of these filters in SSE operate on
|
||||
// one pixel at a time.
|
||||
// So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
|
||||
// They can scale up to 6 and 8 bpp images and down to 2 bpp images,
|
||||
// but they'd not likely have any benefit for 1bpp images.
|
||||
// Most of these can be implemented using only MMX and 64-bit registers,
|
||||
// but they end up a bit slower than using the equally-ubiquitous SSE2.
|
||||
/* The techniques used to implement each of these filters in SSE operate on
|
||||
* one pixel at a time.
|
||||
* So they generally speed up 3bpp images about 3x, 4bpp images about 4x.
|
||||
* They can scale up to 6 and 8 bpp images and down to 2 bpp images,
|
||||
* but they'd not likely have any benefit for 1bpp images.
|
||||
* Most of these can be implemented using only MMX and 64-bit registers,
|
||||
* but they end up a bit slower than using the equally-ubiquitous SSE2.
|
||||
*/
|
||||
if (bpp == 3)
|
||||
{
|
||||
pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2;
|
||||
@ -40,7 +44,9 @@ png_init_filter_functions_sse2(png_structp pp, unsigned int bpp)
|
||||
png_read_filter_row_paeth4_sse2;
|
||||
}
|
||||
|
||||
// No need optimize PNG_FILTER_VALUE_UP. The compiler should autovectorize.
|
||||
/* No need optimize PNG_FILTER_VALUE_UP. The compiler should
|
||||
* autovectorize.
|
||||
*/
|
||||
}
|
||||
|
||||
#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user