diff options
Diffstat (limited to 'media/libpng/sse2')
| -rw-r--r-- | media/libpng/sse2/filter_sse2_intrinsics.c | 379 | ||||
| -rw-r--r-- | media/libpng/sse2/intel_init.c | 54 |
2 files changed, 433 insertions, 0 deletions
diff --git a/media/libpng/sse2/filter_sse2_intrinsics.c b/media/libpng/sse2/filter_sse2_intrinsics.c new file mode 100644 index 000000000..6254e41f1 --- /dev/null +++ b/media/libpng/sse2/filter_sse2_intrinsics.c @@ -0,0 +1,379 @@ + +/* 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) 2014,2016 Glenn Randers-Pehrson + * + * Last changed in libpng 1.6.24 [August 4, 2016] + * + * 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" + +#ifdef PNG_READ_SUPPORTED + +#if PNG_INTEL_SSE_IMPLEMENTATION > 0 + +#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. + */ + +static __m128i load4(const void* p) { + return _mm_cvtsi32_si128(*(const int*)p); +} + +static void store4(void* p, __m128i v) { + *(int*)p = _mm_cvtsi128_si32(v); +} + +static __m128i load3(const void* p) { + /* We'll load 2 bytes, then 1 byte, + * then mask them together, and finally load into SSE. + */ + const png_uint_16* p01 = p; + const png_byte* p2 = (const png_byte*)(p01+1); + + png_uint_32 v012 = (png_uint_32)(*p01) + | (png_uint_32)(*p2) << 16; + return load4(&v012); +} + +static void store3(void* p, __m128i v) { + /* We'll pull from SSE as a 32-bit int, then write + * its bottom two bytes, then its third byte. + */ + png_uint_32 v012; + store4(&v012, v); + + png_uint_16* p01 = p; + png_byte* p2 = (png_byte*)(p01+1); + *p01 = v012; + *p2 = v012 >> 16; +} + +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. + */ + png_debug(1, "in png_read_filter_row_sub3_sse2"); + __m128i a, d = _mm_setzero_si128(); + + int rb = row_info->rowbytes; + while (rb >= 4) { + a = d; d = load4(row); + d = _mm_add_epi8(d, a); + store3(row, d); + + row += 3; + rb -= 3; + } + if (rb > 0) { + a = d; d = load3(row); + d = _mm_add_epi8(d, a); + store3(row, d); + + row += 3; + rb -= 3; + } +} + +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. + */ + png_debug(1, "in png_read_filter_row_sub4_sse2"); + __m128i a, d = _mm_setzero_si128(); + + int rb = row_info->rowbytes; + while (rb > 0) { + a = d; d = load4(row); + d = _mm_add_epi8(d, a); + store4(row, d); + + row += 4; + rb -= 4; + } +} + +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. + */ + png_debug(1, "in png_read_filter_row_avg3_sse2"); + const __m128i zero = _mm_setzero_si128(); + __m128i b; + __m128i a, d = zero; + + int rb = row_info->rowbytes; + while (rb >= 4) { + b = load4(prev); + a = d; d = load4(row ); + + /* 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. */ + avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b), + _mm_set1_epi8(1))); + d = _mm_add_epi8(d, avg); + store3(row, d); + + prev += 3; + row += 3; + rb -= 3; + } + if (rb > 0) { + b = load3(prev); + a = d; d = load3(row ); + + /* 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. */ + avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b), + _mm_set1_epi8(1))); + + d = _mm_add_epi8(d, avg); + store3(row, d); + + prev += 3; + row += 3; + rb -= 3; + } +} + +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. + */ + png_debug(1, "in png_read_filter_row_avg4_sse2"); + const __m128i zero = _mm_setzero_si128(); + __m128i b; + __m128i a, d = zero; + + int rb = row_info->rowbytes; + while (rb > 0) { + b = load4(prev); + a = d; d = load4(row ); + + /* 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. */ + avg = _mm_sub_epi8(avg, _mm_and_si128(_mm_xor_si128(a,b), + _mm_set1_epi8(1))); + + d = _mm_add_epi8(d, avg); + store4(row, d); + + prev += 4; + row += 4; + rb -= 4; + } +} + +/* 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. + */ + __m128i is_negative = _mm_cmplt_epi16(x, _mm_setzero_si128()); + + /* Flip negative lanes. */ + x = _mm_xor_si128(x, is_negative); + + /* +1 to negative lanes, else +0. */ + x = _mm_sub_epi16(x, is_negative); + return x; +#endif +} + +/* 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); +#else + return _mm_or_si128(_mm_and_si128(c, t), _mm_andnot_si128(c, e)); +#endif +} + +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. + */ + png_debug(1, "in png_read_filter_row_paeth3_sse2"); + const __m128i zero = _mm_setzero_si128(); + __m128i c, b = zero, + a, d = zero; + + int rb = row_info->rowbytes; + while (rb >= 4) { + /* 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) */ + __m128i pa = _mm_sub_epi16(b,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) */ + __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| */ + + __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb)); + + /* 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. */ + d = _mm_add_epi8(d, nearest); + store3(row, _mm_packus_epi16(d,d)); + + prev += 3; + row += 3; + rb -= 3; + } + if (rb > 0) { + /* 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) */ + __m128i pa = _mm_sub_epi16(b,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) */ + __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| */ + + __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb)); + + /* 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. */ + d = _mm_add_epi8(d, nearest); + store3(row, _mm_packus_epi16(d,d)); + + prev += 3; + row += 3; + rb -= 3; + } +} + +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. + */ + png_debug(1, "in png_read_filter_row_paeth4_sse2"); + 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. + */ + 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) */ + __m128i pa = _mm_sub_epi16(b,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) */ + __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| */ + + __m128i smallest = _mm_min_epi16(pc, _mm_min_epi16(pa, pb)); + + /* 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. */ + d = _mm_add_epi8(d, nearest); + store4(row, _mm_packus_epi16(d,d)); + + prev += 4; + row += 4; + rb -= 4; + } +} + +#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */ +#endif /* READ */ diff --git a/media/libpng/sse2/intel_init.c b/media/libpng/sse2/intel_init.c new file mode 100644 index 000000000..3f7fd7d3b --- /dev/null +++ b/media/libpng/sse2/intel_init.c @@ -0,0 +1,54 @@ + +/* 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) 2014,2016 Glenn Randers-Pehrson + * + * Last changed in libpng 1.6.22 [May 26, 2016] + * + * 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" + +#ifdef PNG_READ_SUPPORTED +#if PNG_INTEL_SSE_IMPLEMENTATION > 0 + +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. + */ + png_debug(1, "in png_init_filter_functions_sse2"); + if (bpp == 3) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub3_sse2; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg3_sse2; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth3_sse2; + } + else if (bpp == 4) + { + pp->read_filter[PNG_FILTER_VALUE_SUB-1] = png_read_filter_row_sub4_sse2; + pp->read_filter[PNG_FILTER_VALUE_AVG-1] = png_read_filter_row_avg4_sse2; + pp->read_filter[PNG_FILTER_VALUE_PAETH-1] = + png_read_filter_row_paeth4_sse2; + } + + /* No need optimize PNG_FILTER_VALUE_UP. The compiler should + * autovectorize. + */ +} + +#endif /* PNG_INTEL_SSE_IMPLEMENTATION > 0 */ +#endif /* PNG_READ_SUPPORTED */ |