/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "Swizzle.h"
#include <emmintrin.h>
namespace mozilla {
namespace gfx {
// Load 1-3 pixels into a 4 pixel vector.
static MOZ_ALWAYS_INLINE __m128i LoadRemainder_SSE2(const uint8_t* aSrc,
size_t aLength) {
__m128i px;
if (aLength >= 2) {
// Load first 2 pixels
px = _mm_loadl_epi64(reinterpret_cast<const __m128i*>(aSrc));
// Load third pixel
if (aLength >= 3) {
px = _mm_unpacklo_epi64(
px,
_mm_cvtsi32_si128(*reinterpret_cast<const uint32_t*>(aSrc + 2 * 4)));
}
} else {
// Load single pixel
px = _mm_cvtsi32_si128(*reinterpret_cast<const uint32_t*>(aSrc));
}
return px;
}
// Store 1-3 pixels from a vector into memory without overwriting.
static MOZ_ALWAYS_INLINE void StoreRemainder_SSE2(uint8_t* aDst, size_t aLength,
const __m128i& aSrc) {
if (aLength >= 2) {
// Store first 2 pixels
_mm_storel_epi64(reinterpret_cast<__m128i*>(aDst), aSrc);
// Store third pixel
if (aLength >= 3) {
*reinterpret_cast<uint32_t*>(aDst + 2 * 4) =
_mm_cvtsi128_si32(_mm_srli_si128(aSrc, 2 * 4));
}
} else {
// Store single pixel
*reinterpret_cast<uint32_t*>(aDst) = _mm_cvtsi128_si32(aSrc);
}
}
// Premultiply vector of 4 pixels using splayed math.
template <bool aSwapRB, bool aOpaqueAlpha>
static MOZ_ALWAYS_INLINE __m128i PremultiplyVector_SSE2(const __m128i& aSrc) {
// Isolate R and B with mask.
const __m128i mask = _mm_set1_epi32(0x00FF00FF);
__m128i rb = _mm_and_si128(mask, aSrc);
// Swap R and B if necessary.
if (aSwapRB) {
rb = _mm_shufflelo_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
rb = _mm_shufflehi_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
}
// Isolate G and A by shifting down to bottom of word.
__m128i ga = _mm_srli_epi16(aSrc, 8);
// Duplicate alphas to get vector of A1 A1 A2 A2 A3 A3 A4 A4
__m128i alphas = _mm_shufflelo_epi16(ga, _MM_SHUFFLE(3, 3, 1, 1));
alphas = _mm_shufflehi_epi16(alphas, _MM_SHUFFLE(3, 3, 1, 1));
// rb = rb*a + 255; rb += rb >> 8;
rb = _mm_add_epi16(_mm_mullo_epi16(rb, alphas), mask);
rb = _mm_add_epi16(rb, _mm_srli_epi16(rb, 8));
// If format is not opaque, force A to 255 so that A*alpha/255 = alpha
if (!aOpaqueAlpha) {
ga = _mm_or_si128(ga, _mm_set1_epi32(0x00FF0000));
}
// ga = ga*a + 255; ga += ga >> 8;
ga = _mm_add_epi16(_mm_mullo_epi16(ga, alphas), mask);
ga = _mm_add_epi16(ga, _mm_srli_epi16(ga, 8));
// If format is opaque, force output A to be 255.
if (aOpaqueAlpha) {
ga = _mm_or_si128(ga, _mm_set1_epi32(0xFF000000));
}
// Combine back to final pixel with (rb >> 8) | (ga & 0xFF00FF00)
rb = _mm_srli_epi16(rb, 8);
ga = _mm_andnot_si128(mask, ga);
return _mm_or_si128(rb, ga);
}
template <bool aSwapRB, bool aOpaqueAlpha>
void Premultiply_SSE2(const uint8_t* aSrc, int32_t aSrcGap, uint8_t* aDst,
int32_t aDstGap, IntSize aSize) {
int32_t alignedRow = 4 * (aSize.width & ~3);
int32_t remainder = aSize.width & 3;
// Fold remainder into stride gap.
aSrcGap += 4 * remainder;
aDstGap += 4 * remainder;
for (int32_t height = aSize.height; height > 0; height--) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + alignedRow; aSrc < end;) {
__m128i px = _mm_loadu_si128(reinterpret_cast<const __m128i*>(aSrc));
px = PremultiplyVector_SSE2<aSwapRB, aOpaqueAlpha>(px);
_mm_storeu_si128(reinterpret_cast<__m128i*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (remainder) {
__m128i px = LoadRemainder_SSE2(aSrc, remainder);
px = PremultiplyVector_SSE2<aSwapRB, aOpaqueAlpha>(px);
StoreRemainder_SSE2(aDst, remainder, px);
}
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of premultiply variants here.
template void Premultiply_SSE2<false, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_SSE2<false, true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_SSE2<true, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_SSE2<true, true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
// This generates a table of fixed-point reciprocals representing 1/alpha
// similar to the fallback implementation. However, the reciprocal must fit
// in 16 bits to multiply cheaply. Observe that reciprocals of smaller alphas
// require more bits than for larger alphas. We take advantage of this by
// shifting the reciprocal down by either 3 or 8 bits depending on whether
// the alpha value is less than 0x20. This is easy to then undo by multiplying
// the color component to be unpremultiplying by either 8 or 0x100,
// respectively. The 16 bit reciprocal is duplicated into both words of a
// uint32_t here to reduce unpacking overhead.
#define UNPREMULQ_SSE2(x) \
(0x10001U * (0xFF0220U / ((x) * ((x) < 0x20 ? 0x100 : 8))))
#define UNPREMULQ_SSE2_2(x) UNPREMULQ_SSE2(x), UNPREMULQ_SSE2((x) + 1)
#define UNPREMULQ_SSE2_4(x) UNPREMULQ_SSE2_2(x), UNPREMULQ_SSE2_2((x) + 2)
#define UNPREMULQ_SSE2_8(x) UNPREMULQ_SSE2_4(x), UNPREMULQ_SSE2_4((x) + 4)
#define UNPREMULQ_SSE2_16(x) UNPREMULQ_SSE2_8(x), UNPREMULQ_SSE2_8((x) + 8)
#define UNPREMULQ_SSE2_32(x) UNPREMULQ_SSE2_16(x), UNPREMULQ_SSE2_16((x) + 16)
static const uint32_t sUnpremultiplyTable_SSE2[256] = {0,
UNPREMULQ_SSE2(1),
UNPREMULQ_SSE2_2(2),
UNPREMULQ_SSE2_4(4),
UNPREMULQ_SSE2_8(8),
UNPREMULQ_SSE2_16(16),
UNPREMULQ_SSE2_32(32),
UNPREMULQ_SSE2_32(64),
UNPREMULQ_SSE2_32(96),
UNPREMULQ_SSE2_32(128),
UNPREMULQ_SSE2_32(160),
UNPREMULQ_SSE2_32(192),
UNPREMULQ_SSE2_32(224)};
// Unpremultiply a vector of 4 pixels using splayed math and a reciprocal table
// that avoids doing any actual division.
template <bool aSwapRB>
static MOZ_ALWAYS_INLINE __m128i UnpremultiplyVector_SSE2(const __m128i& aSrc) {
// Isolate R and B with mask.
__m128i rb = _mm_and_si128(aSrc, _mm_set1_epi32(0x00FF00FF));
// Swap R and B if necessary.
if (aSwapRB) {
rb = _mm_shufflelo_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
rb = _mm_shufflehi_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
}
// Isolate G and A by shifting down to bottom of word.
__m128i ga = _mm_srli_epi16(aSrc, 8);
// Extract the alphas for the 4 pixels from the now isolated words.
int a1 = _mm_extract_epi16(ga, 1);
int a2 = _mm_extract_epi16(ga, 3);
int a3 = _mm_extract_epi16(ga, 5);
int a4 = _mm_extract_epi16(ga, 7);
// Load the 16 bit reciprocals from the table for each alpha.
// The reciprocals are doubled in each uint32_t entry.
// Unpack them to a final vector of duplicated reciprocals of
// the form Q1 Q1 Q2 Q2 Q3 Q3 Q4 Q4.
__m128i q12 =
_mm_unpacklo_epi32(_mm_cvtsi32_si128(sUnpremultiplyTable_SSE2[a1]),
_mm_cvtsi32_si128(sUnpremultiplyTable_SSE2[a2]));
__m128i q34 =
_mm_unpacklo_epi32(_mm_cvtsi32_si128(sUnpremultiplyTable_SSE2[a3]),
_mm_cvtsi32_si128(sUnpremultiplyTable_SSE2[a4]));
__m128i q1234 = _mm_unpacklo_epi64(q12, q34);
// Check if the alphas are less than 0x20, so that we can undo
// scaling of the reciprocals as appropriate.
__m128i scale = _mm_cmplt_epi32(ga, _mm_set1_epi32(0x00200000));
// Produce scale factors by ((a < 0x20) ^ 8) & 0x108,
// such that scale is 0x100 if < 0x20, and 8 otherwise.
scale = _mm_xor_si128(scale, _mm_set1_epi16(8));
scale = _mm_and_si128(scale, _mm_set1_epi16(0x108));
// Isolate G now so that we don't accidentally unpremultiply A.
ga = _mm_and_si128(ga, _mm_set1_epi32(0x000000FF));
// Scale R, B, and G as required depending on reciprocal precision.
rb = _mm_mullo_epi16(rb, scale);
ga = _mm_mullo_epi16(ga, scale);
// Multiply R, B, and G by the reciprocal, only taking the high word
// too effectively shift right by 16.
rb = _mm_mulhi_epu16(rb, q1234);
ga = _mm_mulhi_epu16(ga, q1234);
// Combine back to final pixel with rb | (ga << 8) | (aSrc & 0xFF000000),
// which will add back on the original alpha value unchanged.
ga = _mm_slli_si128(ga, 1);
ga = _mm_or_si128(ga, _mm_and_si128(aSrc, _mm_set1_epi32(0xFF000000)));
return _mm_or_si128(rb, ga);
}
template <bool aSwapRB>
void Unpremultiply_SSE2(const uint8_t* aSrc, int32_t aSrcGap, uint8_t* aDst,
int32_t aDstGap, IntSize aSize) {
int32_t alignedRow = 4 * (aSize.width & ~3);
int32_t remainder = aSize.width & 3;
// Fold remainder into stride gap.
aSrcGap += 4 * remainder;
aDstGap += 4 * remainder;
for (int32_t height = aSize.height; height > 0; height--) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + alignedRow; aSrc < end;) {
__m128i px = _mm_loadu_si128(reinterpret_cast<const __m128i*>(aSrc));
px = UnpremultiplyVector_SSE2<aSwapRB>(px);
_mm_storeu_si128(reinterpret_cast<__m128i*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (remainder) {
__m128i px = LoadRemainder_SSE2(aSrc, remainder);
px = UnpremultiplyVector_SSE2<aSwapRB>(px);
StoreRemainder_SSE2(aDst, remainder, px);
}
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of unpremultiply variants here.
template void Unpremultiply_SSE2<false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Unpremultiply_SSE2<true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
// Swizzle a vector of 4 pixels providing swaps and opaquifying.
template <bool aSwapRB, bool aOpaqueAlpha>
static MOZ_ALWAYS_INLINE __m128i SwizzleVector_SSE2(const __m128i& aSrc) {
// Isolate R and B.
__m128i rb = _mm_and_si128(aSrc, _mm_set1_epi32(0x00FF00FF));
// Swap R and B.
rb = _mm_shufflelo_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
rb = _mm_shufflehi_epi16(rb, _MM_SHUFFLE(2, 3, 0, 1));
// Isolate G and A.
__m128i ga = _mm_and_si128(aSrc, _mm_set1_epi32(0xFF00FF00));
// Force alpha to 255 if necessary.
if (aOpaqueAlpha) {
ga = _mm_or_si128(ga, _mm_set1_epi32(0xFF000000));
}
// Combine everything back together.
return _mm_or_si128(rb, ga);
}
#if 0
// These specializations currently do not profile faster than the generic versions,
// so disable them for now.
// Optimized implementations for when there is no R and B swap.
template<>
MOZ_ALWAYS_INLINE __m128i
SwizzleVector_SSE2<false, true>(const __m128i& aSrc)
{
// Force alpha to 255.
return _mm_or_si128(aSrc, _mm_set1_epi32(0xFF000000));
}
template<>
MOZ_ALWAYS_INLINE __m128i
SwizzleVector_SSE2<false, false>(const __m128i& aSrc)
{
return aSrc;
}
#endif
template <bool aSwapRB, bool aOpaqueAlpha>
void Swizzle_SSE2(const uint8_t* aSrc, int32_t aSrcGap, uint8_t* aDst,
int32_t aDstGap, IntSize aSize) {
int32_t alignedRow = 4 * (aSize.width & ~3);
int32_t remainder = aSize.width & 3;
// Fold remainder into stride gap.
aSrcGap += 4 * remainder;
aDstGap += 4 * remainder;
for (int32_t height = aSize.height; height > 0; height--) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + alignedRow; aSrc < end;) {
__m128i px = _mm_loadu_si128(reinterpret_cast<const __m128i*>(aSrc));
px = SwizzleVector_SSE2<aSwapRB, aOpaqueAlpha>(px);
_mm_storeu_si128(reinterpret_cast<__m128i*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (remainder) {
__m128i px = LoadRemainder_SSE2(aSrc, remainder);
px = SwizzleVector_SSE2<aSwapRB, aOpaqueAlpha>(px);
StoreRemainder_SSE2(aDst, remainder, px);
}
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of swizzle variants here.
template void Swizzle_SSE2<true, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Swizzle_SSE2<true, true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
} // namespace gfx
} // namespace mozilla