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// Copyright 2014 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// Utilities for processing transparent channel.
//
// Author: Skal (pascal.massimino@gmail.com)
#include "./dsp.h"
#if defined(WEBP_USE_SSE2)
#include <emmintrin.h>
//------------------------------------------------------------------------------
static int DispatchAlpha(const uint8_t* alpha, int alpha_stride,
int width, int height,
uint8_t* dst, int dst_stride) {
// alpha_and stores an 'and' operation of all the alpha[] values. The final
// value is not 0xff if any of the alpha[] is not equal to 0xff.
uint32_t alpha_and = 0xff;
int i, j;
const __m128i zero = _mm_setzero_si128();
const __m128i rgb_mask = _mm_set1_epi32(0xffffff00u); // to preserve RGB
const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
__m128i all_alphas = all_0xff;
// We must be able to access 3 extra bytes after the last written byte
// 'dst[4 * width - 4]', because we don't know if alpha is the first or the
// last byte of the quadruplet.
const int limit = (width - 1) & ~7;
for (j = 0; j < height; ++j) {
__m128i* out = (__m128i*)dst;
for (i = 0; i < limit; i += 8) {
// load 8 alpha bytes
const __m128i a0 = _mm_loadl_epi64((const __m128i*)&alpha[i]);
const __m128i a1 = _mm_unpacklo_epi8(a0, zero);
const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
// load 8 dst pixels (32 bytes)
const __m128i b0_lo = _mm_loadu_si128(out + 0);
const __m128i b0_hi = _mm_loadu_si128(out + 1);
// mask dst alpha values
const __m128i b1_lo = _mm_and_si128(b0_lo, rgb_mask);
const __m128i b1_hi = _mm_and_si128(b0_hi, rgb_mask);
// combine
const __m128i b2_lo = _mm_or_si128(b1_lo, a2_lo);
const __m128i b2_hi = _mm_or_si128(b1_hi, a2_hi);
// store
_mm_storeu_si128(out + 0, b2_lo);
_mm_storeu_si128(out + 1, b2_hi);
// accumulate eight alpha 'and' in parallel
all_alphas = _mm_and_si128(all_alphas, a0);
out += 2;
}
for (; i < width; ++i) {
const uint32_t alpha_value = alpha[i];
dst[4 * i] = alpha_value;
alpha_and &= alpha_value;
}
alpha += alpha_stride;
dst += dst_stride;
}
// Combine the eight alpha 'and' into a 8-bit mask.
alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
return (alpha_and != 0xff);
}
static void DispatchAlphaToGreen(const uint8_t* alpha, int alpha_stride,
int width, int height,
uint32_t* dst, int dst_stride) {
int i, j;
const __m128i zero = _mm_setzero_si128();
const int limit = width & ~15;
for (j = 0; j < height; ++j) {
for (i = 0; i < limit; i += 16) { // process 16 alpha bytes
const __m128i a0 = _mm_loadu_si128((const __m128i*)&alpha[i]);
const __m128i a1 = _mm_unpacklo_epi8(zero, a0); // note the 'zero' first!
const __m128i b1 = _mm_unpackhi_epi8(zero, a0);
const __m128i a2_lo = _mm_unpacklo_epi16(a1, zero);
const __m128i b2_lo = _mm_unpacklo_epi16(b1, zero);
const __m128i a2_hi = _mm_unpackhi_epi16(a1, zero);
const __m128i b2_hi = _mm_unpackhi_epi16(b1, zero);
_mm_storeu_si128((__m128i*)&dst[i + 0], a2_lo);
_mm_storeu_si128((__m128i*)&dst[i + 4], a2_hi);
_mm_storeu_si128((__m128i*)&dst[i + 8], b2_lo);
_mm_storeu_si128((__m128i*)&dst[i + 12], b2_hi);
}
for (; i < width; ++i) dst[i] = alpha[i] << 8;
alpha += alpha_stride;
dst += dst_stride;
}
}
static int ExtractAlpha(const uint8_t* argb, int argb_stride,
int width, int height,
uint8_t* alpha, int alpha_stride) {
// alpha_and stores an 'and' operation of all the alpha[] values. The final
// value is not 0xff if any of the alpha[] is not equal to 0xff.
uint32_t alpha_and = 0xff;
int i, j;
const __m128i a_mask = _mm_set1_epi32(0xffu); // to preserve alpha
const __m128i all_0xff = _mm_set_epi32(0, 0, ~0u, ~0u);
__m128i all_alphas = all_0xff;
// We must be able to access 3 extra bytes after the last written byte
// 'src[4 * width - 4]', because we don't know if alpha is the first or the
// last byte of the quadruplet.
const int limit = (width - 1) & ~7;
for (j = 0; j < height; ++j) {
const __m128i* src = (const __m128i*)argb;
for (i = 0; i < limit; i += 8) {
// load 32 argb bytes
const __m128i a0 = _mm_loadu_si128(src + 0);
const __m128i a1 = _mm_loadu_si128(src + 1);
const __m128i b0 = _mm_and_si128(a0, a_mask);
const __m128i b1 = _mm_and_si128(a1, a_mask);
const __m128i c0 = _mm_packs_epi32(b0, b1);
const __m128i d0 = _mm_packus_epi16(c0, c0);
// store
_mm_storel_epi64((__m128i*)&alpha[i], d0);
// accumulate eight alpha 'and' in parallel
all_alphas = _mm_and_si128(all_alphas, d0);
src += 2;
}
for (; i < width; ++i) {
const uint32_t alpha_value = argb[4 * i];
alpha[i] = alpha_value;
alpha_and &= alpha_value;
}
argb += argb_stride;
alpha += alpha_stride;
}
// Combine the eight alpha 'and' into a 8-bit mask.
alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
return (alpha_and == 0xff);
}
//------------------------------------------------------------------------------
// Non-dither premultiplied modes
#define MULTIPLIER(a) ((a) * 0x8081)
#define PREMULTIPLY(x, m) (((x) * (m)) >> 23)
// We can't use a 'const int' for the SHUFFLE value, because it has to be an
// immediate in the _mm_shufflexx_epi16() instruction. We really a macro here.
#define APPLY_ALPHA(RGBX, SHUFFLE, MASK, MULT) do { \
const __m128i argb0 = _mm_loadl_epi64((__m128i*)&(RGBX)); \
const __m128i argb1 = _mm_unpacklo_epi8(argb0, zero); \
const __m128i alpha0 = _mm_and_si128(argb1, MASK); \
const __m128i alpha1 = _mm_shufflelo_epi16(alpha0, SHUFFLE); \
const __m128i alpha2 = _mm_shufflehi_epi16(alpha1, SHUFFLE); \
/* alpha2 = [0 a0 a0 a0][0 a1 a1 a1] */ \
const __m128i scale0 = _mm_mullo_epi16(alpha2, MULT); \
const __m128i scale1 = _mm_mulhi_epu16(alpha2, MULT); \
const __m128i argb2 = _mm_mulhi_epu16(argb1, scale0); \
const __m128i argb3 = _mm_mullo_epi16(argb1, scale1); \
const __m128i argb4 = _mm_adds_epu16(argb2, argb3); \
const __m128i argb5 = _mm_srli_epi16(argb4, 7); \
const __m128i argb6 = _mm_or_si128(argb5, alpha0); \
const __m128i argb7 = _mm_packus_epi16(argb6, zero); \
_mm_storel_epi64((__m128i*)&(RGBX), argb7); \
} while (0)
static void ApplyAlphaMultiply(uint8_t* rgba, int alpha_first,
int w, int h, int stride) {
const __m128i zero = _mm_setzero_si128();
const int kSpan = 2;
const int w2 = w & ~(kSpan - 1);
while (h-- > 0) {
uint32_t* const rgbx = (uint32_t*)rgba;
int i;
if (!alpha_first) {
const __m128i kMask = _mm_set_epi16(0xff, 0, 0, 0, 0xff, 0, 0, 0);
const __m128i kMult =
_mm_set_epi16(0, 0x8081, 0x8081, 0x8081, 0, 0x8081, 0x8081, 0x8081);
for (i = 0; i < w2; i += kSpan) {
APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 3, 3, 3), kMask, kMult);
}
} else {
const __m128i kMask = _mm_set_epi16(0, 0, 0, 0xff, 0, 0, 0, 0xff);
const __m128i kMult =
_mm_set_epi16(0x8081, 0x8081, 0x8081, 0, 0x8081, 0x8081, 0x8081, 0);
for (i = 0; i < w2; i += kSpan) {
APPLY_ALPHA(rgbx[i], _MM_SHUFFLE(0, 0, 0, 3), kMask, kMult);
}
}
// Finish with left-overs.
for (; i < w; ++i) {
uint8_t* const rgb = rgba + (alpha_first ? 1 : 0);
const uint8_t* const alpha = rgba + (alpha_first ? 0 : 3);
const uint32_t a = alpha[4 * i];
if (a != 0xff) {
const uint32_t mult = MULTIPLIER(a);
rgb[4 * i + 0] = PREMULTIPLY(rgb[4 * i + 0], mult);
rgb[4 * i + 1] = PREMULTIPLY(rgb[4 * i + 1], mult);
rgb[4 * i + 2] = PREMULTIPLY(rgb[4 * i + 2], mult);
}
}
rgba += stride;
}
}
#undef MULTIPLIER
#undef PREMULTIPLY
// -----------------------------------------------------------------------------
// Apply alpha value to rows
// We use: kINV255 = (1 << 24) / 255 = 0x010101
// So: a * kINV255 = (a << 16) | [(a << 8) | a]
// -> _mm_mulhi_epu16() takes care of the (a<<16) part,
// and _mm_mullo_epu16(a * 0x0101,...) takes care of the "(a << 8) | a" one.
static void MultARGBRow(uint32_t* const ptr, int width, int inverse) {
int x = 0;
if (!inverse) {
const int kSpan = 2;
const __m128i zero = _mm_setzero_si128();
const __m128i kRound =
_mm_set_epi16(0, 1 << 7, 1 << 7, 1 << 7, 0, 1 << 7, 1 << 7, 1 << 7);
const __m128i kMult =
_mm_set_epi16(0, 0x0101, 0x0101, 0x0101, 0, 0x0101, 0x0101, 0x0101);
const __m128i kOne64 = _mm_set_epi16(1u << 8, 0, 0, 0, 1u << 8, 0, 0, 0);
const int w2 = width & ~(kSpan - 1);
for (x = 0; x < w2; x += kSpan) {
const __m128i argb0 = _mm_loadl_epi64((__m128i*)&ptr[x]);
const __m128i argb1 = _mm_unpacklo_epi8(argb0, zero);
const __m128i tmp0 = _mm_shufflelo_epi16(argb1, _MM_SHUFFLE(3, 3, 3, 3));
const __m128i tmp1 = _mm_shufflehi_epi16(tmp0, _MM_SHUFFLE(3, 3, 3, 3));
const __m128i tmp2 = _mm_srli_epi64(tmp1, 16);
const __m128i scale0 = _mm_mullo_epi16(tmp1, kMult);
const __m128i scale1 = _mm_or_si128(tmp2, kOne64);
const __m128i argb2 = _mm_mulhi_epu16(argb1, scale0);
const __m128i argb3 = _mm_mullo_epi16(argb1, scale1);
const __m128i argb4 = _mm_adds_epu16(argb2, argb3);
const __m128i argb5 = _mm_adds_epu16(argb4, kRound);
const __m128i argb6 = _mm_srli_epi16(argb5, 8);
const __m128i argb7 = _mm_packus_epi16(argb6, zero);
_mm_storel_epi64((__m128i*)&ptr[x], argb7);
}
}
width -= x;
if (width > 0) WebPMultARGBRowC(ptr + x, width, inverse);
}
static void MultRow(uint8_t* const ptr, const uint8_t* const alpha,
int width, int inverse) {
int x = 0;
if (!inverse) {
const int kSpan = 8;
const __m128i zero = _mm_setzero_si128();
const __m128i kRound = _mm_set1_epi16(1 << 7);
const int w2 = width & ~(kSpan - 1);
for (x = 0; x < w2; x += kSpan) {
const __m128i v0 = _mm_loadl_epi64((__m128i*)&ptr[x]);
const __m128i v1 = _mm_unpacklo_epi8(v0, zero);
const __m128i alpha0 = _mm_loadl_epi64((const __m128i*)&alpha[x]);
const __m128i alpha1 = _mm_unpacklo_epi8(alpha0, zero);
const __m128i alpha2 = _mm_unpacklo_epi8(alpha0, alpha0);
const __m128i v2 = _mm_mulhi_epu16(v1, alpha2);
const __m128i v3 = _mm_mullo_epi16(v1, alpha1);
const __m128i v4 = _mm_adds_epu16(v2, v3);
const __m128i v5 = _mm_adds_epu16(v4, kRound);
const __m128i v6 = _mm_srli_epi16(v5, 8);
const __m128i v7 = _mm_packus_epi16(v6, zero);
_mm_storel_epi64((__m128i*)&ptr[x], v7);
}
}
width -= x;
if (width > 0) WebPMultRowC(ptr + x, alpha + x, width, inverse);
}
//------------------------------------------------------------------------------
// Entry point
extern void WebPInitAlphaProcessingSSE2(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE2(void) {
WebPMultARGBRow = MultARGBRow;
WebPMultRow = MultRow;
WebPApplyAlphaMultiply = ApplyAlphaMultiply;
WebPDispatchAlpha = DispatchAlpha;
WebPDispatchAlphaToGreen = DispatchAlphaToGreen;
WebPExtractAlpha = ExtractAlpha;
}
#else // !WEBP_USE_SSE2
WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingSSE2)
#endif // WEBP_USE_SSE2