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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: */
/* 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
#include "Swizzle.h"
#include <arm_neon.h>
namespace mozilla {
namespace gfx {
// Load 1-3 pixels into a 4 pixel vector.
static MOZ_ALWAYS_INLINE uint16x8_t LoadRemainder_NEON(const uint8_t* aSrc,
size_t aLength) {
const uint32_t* src32 = reinterpret_cast<const uint32_t*>(aSrc);
uint32x4_t dst32;
if (aLength >= 2) {
// Load first 2 pixels
dst32 = vcombine_u32(vld1_u32(src32), vdup_n_u32(0));
// Load third pixel
if (aLength >= 3) {
dst32 = vld1q_lane_u32(src32 + 2, dst32, 2);
}
} else {
// Load single pixel
dst32 = vld1q_lane_u32(src32, vdupq_n_u32(0), 0);
}
return vreinterpretq_u16_u32(dst32);
}
// Store 1-3 pixels from a vector into memory without overwriting.
static MOZ_ALWAYS_INLINE void StoreRemainder_NEON(uint8_t* aDst, size_t aLength,
const uint16x8_t& aSrc) {
uint32_t* dst32 = reinterpret_cast<uint32_t*>(aDst);
uint32x4_t src32 = vreinterpretq_u32_u16(aSrc);
if (aLength >= 2) {
// Store first 2 pixels
vst1_u32(dst32, vget_low_u32(src32));
// Store third pixel
if (aLength >= 3) {
vst1q_lane_u32(dst32 + 2, src32, 2);
}
} else {
// Store single pixel
vst1q_lane_u32(dst32, src32, 0);
}
}
// Premultiply vector of 4 pixels using splayed math.
template <bool aSwapRB, bool aOpaqueAlpha>
static MOZ_ALWAYS_INLINE uint16x8_t
PremultiplyVector_NEON(const uint16x8_t& aSrc) {
// Isolate R and B with mask.
const uint16x8_t mask = vdupq_n_u16(0x00FF);
uint16x8_t rb = vandq_u16(aSrc, mask);
// Swap R and B if necessary.
if (aSwapRB) {
rb = vrev32q_u16(rb);
}
// Isolate G and A by shifting down to bottom of word.
uint16x8_t ga = vshrq_n_u16(aSrc, 8);
// Duplicate alphas to get vector of A1 A1 A2 A2 A3 A3 A4 A4
uint16x8_t alphas = vtrnq_u16(ga, ga).val[1];
// rb = rb*a + 255; rb += rb >> 8;
rb = vmlaq_u16(mask, rb, alphas);
rb = vsraq_n_u16(rb, rb, 8);
// If format is not opaque, force A to 255 so that A*alpha/255 = alpha
if (!aOpaqueAlpha) {
ga = vorrq_u16(ga, vreinterpretq_u16_u32(vdupq_n_u32(0x00FF0000)));
}
// ga = ga*a + 255; ga += ga >> 8;
ga = vmlaq_u16(mask, ga, alphas);
ga = vsraq_n_u16(ga, ga, 8);
// If format is opaque, force output A to be 255.
if (aOpaqueAlpha) {
ga = vorrq_u16(ga, vreinterpretq_u16_u32(vdupq_n_u32(0xFF000000)));
}
// Combine back to final pixel with (rb >> 8) | (ga & 0xFF00FF00)
return vsriq_n_u16(ga, rb, 8);
}
template <bool aSwapRB, bool aOpaqueAlpha>
static MOZ_ALWAYS_INLINE void PremultiplyChunk_NEON(const uint8_t*& aSrc,
uint8_t*& aDst,
int32_t aAlignedRow,
int32_t aRemainder) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + aAlignedRow; aSrc < end;) {
uint16x8_t px = vld1q_u16(reinterpret_cast<const uint16_t*>(aSrc));
px = PremultiplyVector_NEON<aSwapRB, aOpaqueAlpha>(px);
vst1q_u16(reinterpret_cast<uint16_t*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (aRemainder) {
uint16x8_t px = LoadRemainder_NEON(aSrc, aRemainder);
px = PremultiplyVector_NEON<aSwapRB, aOpaqueAlpha>(px);
StoreRemainder_NEON(aDst, aRemainder, px);
}
}
template <bool aSwapRB, bool aOpaqueAlpha>
void PremultiplyRow_NEON(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
int32_t alignedRow = 4 * (aLength & ~3);
int32_t remainder = aLength & 3;
PremultiplyChunk_NEON<aSwapRB, aOpaqueAlpha>(aSrc, aDst, alignedRow,
remainder);
}
template <bool aSwapRB, bool aOpaqueAlpha>
void Premultiply_NEON(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--) {
PremultiplyChunk_NEON<aSwapRB, aOpaqueAlpha>(aSrc, aDst, alignedRow,
remainder);
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of premultiply variants here.
template void PremultiplyRow_NEON<false, false>(const uint8_t*, uint8_t*,
int32_t);
template void PremultiplyRow_NEON<false, true>(const uint8_t*, uint8_t*,
int32_t);
template void PremultiplyRow_NEON<true, false>(const uint8_t*, uint8_t*,
int32_t);
template void PremultiplyRow_NEON<true, true>(const uint8_t*, uint8_t*,
int32_t);
template void Premultiply_NEON<false, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_NEON<false, true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_NEON<true, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Premultiply_NEON<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
// ultimately be multiplied as an unsigned 9 bit upper part and a signed
// 15 bit lower part to cheaply multiply. Thus, the lower 15 bits of the
// reciprocal is stored 15 bits of the reciprocal are masked off and
// stored in the low word. The upper 9 bits are masked and shifted to fit
// into the high word. These then get independently multiplied with the
// color component and recombined to provide the full recriprocal multiply.
#define UNPREMULQ_NEON(x) \
((((0xFF00FFU / (x)) & 0xFF8000U) << 1) | ((0xFF00FFU / (x)) & 0x7FFFU))
#define UNPREMULQ_NEON_2(x) UNPREMULQ_NEON(x), UNPREMULQ_NEON((x) + 1)
#define UNPREMULQ_NEON_4(x) UNPREMULQ_NEON_2(x), UNPREMULQ_NEON_2((x) + 2)
#define UNPREMULQ_NEON_8(x) UNPREMULQ_NEON_4(x), UNPREMULQ_NEON_4((x) + 4)
#define UNPREMULQ_NEON_16(x) UNPREMULQ_NEON_8(x), UNPREMULQ_NEON_8((x) + 8)
#define UNPREMULQ_NEON_32(x) UNPREMULQ_NEON_16(x), UNPREMULQ_NEON_16((x) + 16)
static const uint32_t sUnpremultiplyTable_NEON[256] = {0,
UNPREMULQ_NEON(1),
UNPREMULQ_NEON_2(2),
UNPREMULQ_NEON_4(4),
UNPREMULQ_NEON_8(8),
UNPREMULQ_NEON_16(16),
UNPREMULQ_NEON_32(32),
UNPREMULQ_NEON_32(64),
UNPREMULQ_NEON_32(96),
UNPREMULQ_NEON_32(128),
UNPREMULQ_NEON_32(160),
UNPREMULQ_NEON_32(192),
UNPREMULQ_NEON_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 uint16x8_t
UnpremultiplyVector_NEON(const uint16x8_t& aSrc) {
// Isolate R and B with mask.
uint16x8_t rb = vandq_u16(aSrc, vdupq_n_u16(0x00FF));
// Swap R and B if necessary.
if (aSwapRB) {
rb = vrev32q_u16(rb);
}
// Isolate G and A by shifting down to bottom of word.
uint16x8_t ga = vshrq_n_u16(aSrc, 8);
// Extract the alphas for the 4 pixels from the now isolated words.
int a1 = vgetq_lane_u16(ga, 1);
int a2 = vgetq_lane_u16(ga, 3);
int a3 = vgetq_lane_u16(ga, 5);
int a4 = vgetq_lane_u16(ga, 7);
// First load all of the interleaved low and high portions of the reciprocals
// and combine them a single vector as lo1 hi1 lo2 hi2 lo3 hi3 lo4 hi4
uint16x8_t q1234 = vreinterpretq_u16_u32(vld1q_lane_u32(
&sUnpremultiplyTable_NEON[a4],
vld1q_lane_u32(
&sUnpremultiplyTable_NEON[a3],
vld1q_lane_u32(
&sUnpremultiplyTable_NEON[a2],
vld1q_lane_u32(&sUnpremultiplyTable_NEON[a1], vdupq_n_u32(0), 0),
1),
2),
3));
// Transpose the interleaved low/high portions so that we produce
// two separate duplicated vectors for the low and high portions respectively:
// lo1 lo1 lo2 lo2 lo3 lo3 lo4 lo4 and hi1 hi1 hi2 hi2 hi3 hi3 hi4 hi4
uint16x8x2_t q1234lohi = vtrnq_u16(q1234, q1234);
// VQDMULH is a signed multiply that doubles (*2) the result, then takes the
// high word. To work around the signedness and the doubling, the low
// portion of the reciprocal only stores the lower 15 bits, which fits in a
// signed 16 bit integer. The high 9 bit portion is effectively also doubled
// by 2 as a side-effect of being shifted for storage. Thus the output scale
// of doing a normal multiply by the high portion and the VQDMULH by the low
// portion are both doubled and can be safely added together. The resulting
// sum just needs to be halved (via VHADD) to thus cancel out the doubling.
// All this combines to produce a reciprocal multiply of the form:
// rb = ((rb * hi) + ((rb * lo * 2) >> 16)) / 2
rb = vhaddq_u16(
vmulq_u16(rb, q1234lohi.val[1]),
vreinterpretq_u16_s16(vqdmulhq_s16(
vreinterpretq_s16_u16(rb), vreinterpretq_s16_u16(q1234lohi.val[0]))));
// ga = ((ga * hi) + ((ga * lo * 2) >> 16)) / 2
ga = vhaddq_u16(
vmulq_u16(ga, q1234lohi.val[1]),
vreinterpretq_u16_s16(vqdmulhq_s16(
vreinterpretq_s16_u16(ga), vreinterpretq_s16_u16(q1234lohi.val[0]))));
// Combine to the final pixel with ((rb | (ga << 8)) & ~0xFF000000) | (aSrc &
// 0xFF000000), which inserts back in the original alpha value unchanged.
return vbslq_u16(vreinterpretq_u16_u32(vdupq_n_u32(0xFF000000)), aSrc,
vsliq_n_u16(rb, ga, 8));
}
template <bool aSwapRB>
static MOZ_ALWAYS_INLINE void UnpremultiplyChunk_NEON(const uint8_t*& aSrc,
uint8_t*& aDst,
int32_t aAlignedRow,
int32_t aRemainder) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + aAlignedRow; aSrc < end;) {
uint16x8_t px = vld1q_u16(reinterpret_cast<const uint16_t*>(aSrc));
px = UnpremultiplyVector_NEON<aSwapRB>(px);
vst1q_u16(reinterpret_cast<uint16_t*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (aRemainder) {
uint16x8_t px = LoadRemainder_NEON(aSrc, aRemainder);
px = UnpremultiplyVector_NEON<aSwapRB>(px);
StoreRemainder_NEON(aDst, aRemainder, px);
}
}
template <bool aSwapRB>
void UnpremultiplyRow_NEON(const uint8_t* aSrc, uint8_t* aDst,
int32_t aLength) {
int32_t alignedRow = 4 * (aLength & ~3);
int32_t remainder = aLength & 3;
UnpremultiplyChunk_NEON<aSwapRB>(aSrc, aDst, alignedRow, remainder);
}
template <bool aSwapRB>
void Unpremultiply_NEON(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--) {
UnpremultiplyChunk_NEON<aSwapRB>(aSrc, aDst, alignedRow, remainder);
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of unpremultiply variants here.
template void UnpremultiplyRow_NEON<false>(const uint8_t*, uint8_t*, int32_t);
template void UnpremultiplyRow_NEON<true>(const uint8_t*, uint8_t*, int32_t);
template void Unpremultiply_NEON<false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Unpremultiply_NEON<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 uint16x8_t SwizzleVector_NEON(const uint16x8_t& aSrc) {
// Swap R and B, then add to G and A (forced to 255):
// (((src>>16) | (src << 16)) & 0x00FF00FF) |
// ((src | 0xFF000000) & ~0x00FF00FF)
return vbslq_u16(
vdupq_n_u16(0x00FF), vrev32q_u16(aSrc),
aOpaqueAlpha
? vorrq_u16(aSrc, vreinterpretq_u16_u32(vdupq_n_u32(0xFF000000)))
: aSrc);
}
#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<>
static MOZ_ALWAYS_INLINE uint16x8_t
SwizzleVector_NEON<false, true>(const uint16x8_t& aSrc)
{
// Force alpha to 255.
return vorrq_u16(aSrc, vreinterpretq_u16_u32(vdupq_n_u32(0xFF000000)));
}
template<>
static MOZ_ALWAYS_INLINE uint16x8_t
SwizzleVector_NEON<false, false>(const uint16x8_t& aSrc)
{
return aSrc;
}
#endif
template <bool aSwapRB, bool aOpaqueAlpha>
static MOZ_ALWAYS_INLINE void SwizzleChunk_NEON(const uint8_t*& aSrc,
uint8_t*& aDst,
int32_t aAlignedRow,
int32_t aRemainder) {
// Process all 4-pixel chunks as one vector.
for (const uint8_t* end = aSrc + aAlignedRow; aSrc < end;) {
uint16x8_t px = vld1q_u16(reinterpret_cast<const uint16_t*>(aSrc));
px = SwizzleVector_NEON<aSwapRB, aOpaqueAlpha>(px);
vst1q_u16(reinterpret_cast<uint16_t*>(aDst), px);
aSrc += 4 * 4;
aDst += 4 * 4;
}
// Handle any 1-3 remaining pixels.
if (aRemainder) {
uint16x8_t px = LoadRemainder_NEON(aSrc, aRemainder);
px = SwizzleVector_NEON<aSwapRB, aOpaqueAlpha>(px);
StoreRemainder_NEON(aDst, aRemainder, px);
}
}
template <bool aSwapRB, bool aOpaqueAlpha>
void SwizzleRow_NEON(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
int32_t alignedRow = 4 * (aLength & ~3);
int32_t remainder = aLength & 3;
SwizzleChunk_NEON<aSwapRB, aOpaqueAlpha>(aSrc, aDst, alignedRow, remainder);
}
template <bool aSwapRB, bool aOpaqueAlpha>
void Swizzle_NEON(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--) {
SwizzleChunk_NEON<aSwapRB, aOpaqueAlpha>(aSrc, aDst, alignedRow, remainder);
aSrc += aSrcGap;
aDst += aDstGap;
}
}
// Force instantiation of swizzle variants here.
template void SwizzleRow_NEON<true, false>(const uint8_t*, uint8_t*, int32_t);
template void SwizzleRow_NEON<true, true>(const uint8_t*, uint8_t*, int32_t);
template void Swizzle_NEON<true, false>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template void Swizzle_NEON<true, true>(const uint8_t*, int32_t, uint8_t*,
int32_t, IntSize);
template <bool aSwapRB>
void UnpackRowRGB24(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength);
template <bool aSwapRB>
void UnpackRowRGB24_NEON(const uint8_t* aSrc, uint8_t* aDst, int32_t aLength) {
// Because this implementation will read an additional 4 bytes of data that
// is ignored and masked over, we cannot use the accelerated version for the
// last 1-5 pixels (3-15 bytes remaining) to guarantee we don't access memory
// outside the buffer (we read in 16 byte chunks).
if (aLength < 6) {
UnpackRowRGB24<aSwapRB>(aSrc, aDst, aLength);
return;
}
// Because we are expanding, we can only process the data back to front in
// case we are performing this in place.
int32_t alignedRow = (aLength - 2) & ~3;
int32_t remainder = aLength - alignedRow;
const uint8_t* src = aSrc + alignedRow * 3;
uint8_t* dst = aDst + alignedRow * 4;
// Handle 2-5 remaining pixels.
UnpackRowRGB24<aSwapRB>(src, dst, remainder);
uint8x8_t masklo;
uint8x8_t maskhi;
if (aSwapRB) {
static const uint8_t masklo_data[] = {2, 1, 0, 0, 5, 4, 3, 0};
static const uint8_t maskhi_data[] = {4, 3, 2, 0, 7, 6, 5, 0};
masklo = vld1_u8(masklo_data);
maskhi = vld1_u8(maskhi_data);
} else {
static const uint8_t masklo_data[] = {0, 1, 2, 0, 3, 4, 5, 0};
static const uint8_t maskhi_data[] = {2, 3, 4, 0, 5, 6, 7, 0};
masklo = vld1_u8(masklo_data);
maskhi = vld1_u8(maskhi_data);
}
uint8x16_t alpha = vreinterpretq_u8_u32(vdupq_n_u32(0xFF000000));
// Process all 4-pixel chunks as one vector.
src -= 4 * 3;
dst -= 4 * 4;
while (src >= aSrc) {
uint8x16_t px = vld1q_u8(src);
// G2R2B1G1 R1B0G0R0 -> X1R1G1B1 X0R0G0B0
uint8x8_t pxlo = vtbl1_u8(vget_low_u8(px), masklo);
// B3G3R3B2 G2R2B1G1 -> X3R3G3B3 X2R2G2B2
uint8x8_t pxhi =
vtbl1_u8(vext_u8(vget_low_u8(px), vget_high_u8(px), 4), maskhi);
px = vcombine_u8(pxlo, pxhi);
px = vorrq_u8(px, alpha);
vst1q_u8(dst, px);
src -= 4 * 3;
dst -= 4 * 4;
}
}
// Force instantiation of swizzle variants here.
template void UnpackRowRGB24_NEON<false>(const uint8_t*, uint8_t*, int32_t);
template void UnpackRowRGB24_NEON<true>(const uint8_t*, uint8_t*, int32_t);
} // namespace gfx
} // namespace mozilla