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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
// Copyright (c) 2011-2016 Google Inc.
// Use of this source code is governed by a BSD-style license that can be
// found in the gfx/skia/LICENSE file.
#include "SkConvolver.h"
#include "mozilla/Attributes.h"
#include <immintrin.h>
namespace skia {
static MOZ_ALWAYS_INLINE void AccumRemainder(
const unsigned char* pixelsLeft,
const SkConvolutionFilter1D::ConvolutionFixed* filterValues, __m128i& accum,
int r) {
int remainder[4] = {0};
for (int i = 0; i < r; i++) {
SkConvolutionFilter1D::ConvolutionFixed coeff = filterValues[i];
remainder[0] += coeff * pixelsLeft[i * 4 + 0];
remainder[1] += coeff * pixelsLeft[i * 4 + 1];
remainder[2] += coeff * pixelsLeft[i * 4 + 2];
remainder[3] += coeff * pixelsLeft[i * 4 + 3];
}
__m128i t =
_mm_setr_epi32(remainder[0], remainder[1], remainder[2], remainder[3]);
accum = _mm_add_epi32(accum, t);
}
// Convolves horizontally along a single row. The row data is given in
// |srcData| and continues for the numValues() of the filter.
void convolve_horizontally_sse2(const unsigned char* srcData,
const SkConvolutionFilter1D& filter,
unsigned char* outRow, bool /*hasAlpha*/) {
// Output one pixel each iteration, calculating all channels (RGBA) together.
int numValues = filter.numValues();
for (int outX = 0; outX < numValues; outX++) {
// Get the filter that determines the current output pixel.
int filterOffset, filterLength;
const SkConvolutionFilter1D::ConvolutionFixed* filterValues =
filter.FilterForValue(outX, &filterOffset, &filterLength);
// Compute the first pixel in this row that the filter affects. It will
// touch |filterLength| pixels (4 bytes each) after this.
const unsigned char* rowToFilter = &srcData[filterOffset * 4];
__m128i zero = _mm_setzero_si128();
__m128i accum = _mm_setzero_si128();
// We will load and accumulate with four coefficients per iteration.
for (int filterX = 0; filterX < filterLength >> 2; filterX++) {
// Load 4 coefficients => duplicate 1st and 2nd of them for all channels.
__m128i coeff, coeff16;
// [16] xx xx xx xx c3 c2 c1 c0
coeff = _mm_loadl_epi64(reinterpret_cast<const __m128i*>(filterValues));
// [16] xx xx xx xx c1 c1 c0 c0
coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(1, 1, 0, 0));
// [16] c1 c1 c1 c1 c0 c0 c0 c0
coeff16 = _mm_unpacklo_epi16(coeff16, coeff16);
// Load four pixels => unpack the first two pixels to 16 bits =>
// multiply with coefficients => accumulate the convolution result.
// [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0
__m128i src8 =
_mm_loadu_si128(reinterpret_cast<const __m128i*>(rowToFilter));
// [16] a1 b1 g1 r1 a0 b0 g0 r0
__m128i src16 = _mm_unpacklo_epi8(src8, zero);
__m128i mul_hi = _mm_mulhi_epi16(src16, coeff16);
__m128i mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a0*c0 b0*c0 g0*c0 r0*c0
__m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum = _mm_add_epi32(accum, t);
// [32] a1*c1 b1*c1 g1*c1 r1*c1
t = _mm_unpackhi_epi16(mul_lo, mul_hi);
accum = _mm_add_epi32(accum, t);
// Duplicate 3rd and 4th coefficients for all channels =>
// unpack the 3rd and 4th pixels to 16 bits => multiply with coefficients
// => accumulate the convolution results.
// [16] xx xx xx xx c3 c3 c2 c2
coeff16 = _mm_shufflelo_epi16(coeff, _MM_SHUFFLE(3, 3, 2, 2));
// [16] c3 c3 c3 c3 c2 c2 c2 c2
coeff16 = _mm_unpacklo_epi16(coeff16, coeff16);
// [16] a3 g3 b3 r3 a2 g2 b2 r2
src16 = _mm_unpackhi_epi8(src8, zero);
mul_hi = _mm_mulhi_epi16(src16, coeff16);
mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a2*c2 b2*c2 g2*c2 r2*c2
t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum = _mm_add_epi32(accum, t);
// [32] a3*c3 b3*c3 g3*c3 r3*c3
t = _mm_unpackhi_epi16(mul_lo, mul_hi);
accum = _mm_add_epi32(accum, t);
// Advance the pixel and coefficients pointers.
rowToFilter += 16;
filterValues += 4;
}
// When |filterLength| is not divisible by 4, we accumulate the last 1 - 3
// coefficients one at a time.
int r = filterLength & 3;
if (r) {
int remainderOffset = (filterOffset + filterLength - r) * 4;
AccumRemainder(srcData + remainderOffset, filterValues, accum, r);
}
// Shift right for fixed point implementation.
accum = _mm_srai_epi32(accum, SkConvolutionFilter1D::kShiftBits);
// Packing 32 bits |accum| to 16 bits per channel (signed saturation).
accum = _mm_packs_epi32(accum, zero);
// Packing 16 bits |accum| to 8 bits per channel (unsigned saturation).
accum = _mm_packus_epi16(accum, zero);
// Store the pixel value of 32 bits.
*(reinterpret_cast<int*>(outRow)) = _mm_cvtsi128_si32(accum);
outRow += 4;
}
}
// Does vertical convolution to produce one output row. The filter values and
// length are given in the first two parameters. These are applied to each
// of the rows pointed to in the |sourceDataRows| array, with each row
// being |pixelWidth| wide.
//
// The output must have room for |pixelWidth * 4| bytes.
template <bool hasAlpha>
static void ConvolveVertically(
const SkConvolutionFilter1D::ConvolutionFixed* filterValues,
int filterLength, unsigned char* const* sourceDataRows, int pixelWidth,
unsigned char* outRow) {
// Output four pixels per iteration (16 bytes).
int width = pixelWidth & ~3;
__m128i zero = _mm_setzero_si128();
for (int outX = 0; outX < width; outX += 4) {
// Accumulated result for each pixel. 32 bits per RGBA channel.
__m128i accum0 = _mm_setzero_si128();
__m128i accum1 = _mm_setzero_si128();
__m128i accum2 = _mm_setzero_si128();
__m128i accum3 = _mm_setzero_si128();
// Convolve with one filter coefficient per iteration.
for (int filterY = 0; filterY < filterLength; filterY++) {
// Duplicate the filter coefficient 8 times.
// [16] cj cj cj cj cj cj cj cj
__m128i coeff16 = _mm_set1_epi16(filterValues[filterY]);
// Load four pixels (16 bytes) together.
// [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0
const __m128i* src =
reinterpret_cast<const __m128i*>(&sourceDataRows[filterY][outX << 2]);
__m128i src8 = _mm_loadu_si128(src);
// Unpack 1st and 2nd pixels from 8 bits to 16 bits for each channels =>
// multiply with current coefficient => accumulate the result.
// [16] a1 b1 g1 r1 a0 b0 g0 r0
__m128i src16 = _mm_unpacklo_epi8(src8, zero);
__m128i mul_hi = _mm_mulhi_epi16(src16, coeff16);
__m128i mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a0 b0 g0 r0
__m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum0 = _mm_add_epi32(accum0, t);
// [32] a1 b1 g1 r1
t = _mm_unpackhi_epi16(mul_lo, mul_hi);
accum1 = _mm_add_epi32(accum1, t);
// Unpack 3rd and 4th pixels from 8 bits to 16 bits for each channels =>
// multiply with current coefficient => accumulate the result.
// [16] a3 b3 g3 r3 a2 b2 g2 r2
src16 = _mm_unpackhi_epi8(src8, zero);
mul_hi = _mm_mulhi_epi16(src16, coeff16);
mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a2 b2 g2 r2
t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum2 = _mm_add_epi32(accum2, t);
// [32] a3 b3 g3 r3
t = _mm_unpackhi_epi16(mul_lo, mul_hi);
accum3 = _mm_add_epi32(accum3, t);
}
// Shift right for fixed point implementation.
accum0 = _mm_srai_epi32(accum0, SkConvolutionFilter1D::kShiftBits);
accum1 = _mm_srai_epi32(accum1, SkConvolutionFilter1D::kShiftBits);
accum2 = _mm_srai_epi32(accum2, SkConvolutionFilter1D::kShiftBits);
accum3 = _mm_srai_epi32(accum3, SkConvolutionFilter1D::kShiftBits);
// Packing 32 bits |accum| to 16 bits per channel (signed saturation).
// [16] a1 b1 g1 r1 a0 b0 g0 r0
accum0 = _mm_packs_epi32(accum0, accum1);
// [16] a3 b3 g3 r3 a2 b2 g2 r2
accum2 = _mm_packs_epi32(accum2, accum3);
// Packing 16 bits |accum| to 8 bits per channel (unsigned saturation).
// [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0
accum0 = _mm_packus_epi16(accum0, accum2);
if (hasAlpha) {
// Compute the max(ri, gi, bi) for each pixel.
// [8] xx a3 b3 g3 xx a2 b2 g2 xx a1 b1 g1 xx a0 b0 g0
__m128i a = _mm_srli_epi32(accum0, 8);
// [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0
__m128i b = _mm_max_epu8(a, accum0); // Max of r and g.
// [8] xx xx a3 b3 xx xx a2 b2 xx xx a1 b1 xx xx a0 b0
a = _mm_srli_epi32(accum0, 16);
// [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0
b = _mm_max_epu8(a, b); // Max of r and g and b.
// [8] max3 00 00 00 max2 00 00 00 max1 00 00 00 max0 00 00 00
b = _mm_slli_epi32(b, 24);
// Make sure the value of alpha channel is always larger than maximum
// value of color channels.
accum0 = _mm_max_epu8(b, accum0);
} else {
// Set value of alpha channels to 0xFF.
__m128i mask = _mm_set1_epi32(0xff000000);
accum0 = _mm_or_si128(accum0, mask);
}
// Store the convolution result (16 bytes) and advance the pixel pointers.
_mm_storeu_si128(reinterpret_cast<__m128i*>(outRow), accum0);
outRow += 16;
}
// When the width of the output is not divisible by 4, We need to save one
// pixel (4 bytes) each time. And also the fourth pixel is always absent.
int r = pixelWidth & 3;
if (r) {
__m128i accum0 = _mm_setzero_si128();
__m128i accum1 = _mm_setzero_si128();
__m128i accum2 = _mm_setzero_si128();
for (int filterY = 0; filterY < filterLength; ++filterY) {
__m128i coeff16 = _mm_set1_epi16(filterValues[filterY]);
// [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0
const __m128i* src = reinterpret_cast<const __m128i*>(
&sourceDataRows[filterY][width << 2]);
__m128i src8 = _mm_loadu_si128(src);
// [16] a1 b1 g1 r1 a0 b0 g0 r0
__m128i src16 = _mm_unpacklo_epi8(src8, zero);
__m128i mul_hi = _mm_mulhi_epi16(src16, coeff16);
__m128i mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a0 b0 g0 r0
__m128i t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum0 = _mm_add_epi32(accum0, t);
// [32] a1 b1 g1 r1
t = _mm_unpackhi_epi16(mul_lo, mul_hi);
accum1 = _mm_add_epi32(accum1, t);
// [16] a3 b3 g3 r3 a2 b2 g2 r2
src16 = _mm_unpackhi_epi8(src8, zero);
mul_hi = _mm_mulhi_epi16(src16, coeff16);
mul_lo = _mm_mullo_epi16(src16, coeff16);
// [32] a2 b2 g2 r2
t = _mm_unpacklo_epi16(mul_lo, mul_hi);
accum2 = _mm_add_epi32(accum2, t);
}
accum0 = _mm_srai_epi32(accum0, SkConvolutionFilter1D::kShiftBits);
accum1 = _mm_srai_epi32(accum1, SkConvolutionFilter1D::kShiftBits);
accum2 = _mm_srai_epi32(accum2, SkConvolutionFilter1D::kShiftBits);
// [16] a1 b1 g1 r1 a0 b0 g0 r0
accum0 = _mm_packs_epi32(accum0, accum1);
// [16] a3 b3 g3 r3 a2 b2 g2 r2
accum2 = _mm_packs_epi32(accum2, zero);
// [8] a3 b3 g3 r3 a2 b2 g2 r2 a1 b1 g1 r1 a0 b0 g0 r0
accum0 = _mm_packus_epi16(accum0, accum2);
if (hasAlpha) {
// [8] xx a3 b3 g3 xx a2 b2 g2 xx a1 b1 g1 xx a0 b0 g0
__m128i a = _mm_srli_epi32(accum0, 8);
// [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0
__m128i b = _mm_max_epu8(a, accum0); // Max of r and g.
// [8] xx xx a3 b3 xx xx a2 b2 xx xx a1 b1 xx xx a0 b0
a = _mm_srli_epi32(accum0, 16);
// [8] xx xx xx max3 xx xx xx max2 xx xx xx max1 xx xx xx max0
b = _mm_max_epu8(a, b); // Max of r and g and b.
// [8] max3 00 00 00 max2 00 00 00 max1 00 00 00 max0 00 00 00
b = _mm_slli_epi32(b, 24);
accum0 = _mm_max_epu8(b, accum0);
} else {
__m128i mask = _mm_set1_epi32(0xff000000);
accum0 = _mm_or_si128(accum0, mask);
}
for (int i = 0; i < r; i++) {
*(reinterpret_cast<int*>(outRow)) = _mm_cvtsi128_si32(accum0);
accum0 = _mm_srli_si128(accum0, 4);
outRow += 4;
}
}
}
void convolve_vertically_sse2(
const SkConvolutionFilter1D::ConvolutionFixed* filterValues,
int filterLength, unsigned char* const* sourceDataRows, int pixelWidth,
unsigned char* outRow, bool hasAlpha) {
if (hasAlpha) {
ConvolveVertically<true>(filterValues, filterLength, sourceDataRows,
pixelWidth, outRow);
} else {
ConvolveVertically<false>(filterValues, filterLength, sourceDataRows,
pixelWidth, outRow);
}
}
} // namespace skia