/*
* Copyright 2018 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkBitmapProcState_opts_DEFINED
#define SkBitmapProcState_opts_DEFINED
#include "SkBitmapProcState.h"
// SkBitmapProcState optimized Shader, Sample, or Matrix procs.
//
// Only S32_alpha_D32_filter_DX exploits instructions beyond
// our common baseline SSE2/NEON instruction sets, so that's
// all that lives here.
//
// The rest are scattershot at the moment but I want to get them
// all migrated to be normal code inside SkBitmapProcState.cpp.
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
#include <immintrin.h>
#elif defined(SK_ARM_HAS_NEON)
#include <arm_neon.h>
#endif
namespace SK_OPTS_NS {
// This same basic packing scheme is used throughout the file.
static void decode_packed_coordinates_and_weight(uint32_t packed, int* v0, int* v1, int* w) {
// The top 14 bits are the integer coordinate x0 or y0.
*v0 = packed >> 18;
// The bottom 14 bits are the integer coordinate x1 or y1.
*v1 = packed & 0x3fff;
// The middle 4 bits are the interpolating factor between the two, i.e. the weight for v1.
*w = (packed >> 14) & 0xf;
}
#if 1 && SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSSE3
// As above, 4x.
static void decode_packed_coordinates_and_weight(__m128i packed,
int v0[4], int v1[4], __m128i* w) {
_mm_storeu_si128((__m128i*)v0, _mm_srli_epi32(packed, 18));
_mm_storeu_si128((__m128i*)v1, _mm_and_si128 (packed, _mm_set1_epi32(0x3fff)));
*w = _mm_and_si128(_mm_srli_epi32(packed, 14), _mm_set1_epi32(0xf));
}
// This is the crux of the SSSE3 implementation,
// interpolating in X for up to two output pixels (A and B) using _mm_maddubs_epi16().
static inline __m128i interpolate_in_x(uint32_t A0, uint32_t A1,
uint32_t B0, uint32_t B1,
const __m128i& interlaced_x_weights) {
// _mm_maddubs_epi16() is a little idiosyncratic, but very helpful as the core of a lerp.
//
// It takes two arguments interlaced byte-wise:
// - first arg: [ x,y, ... 7 more pairs of 8-bit values ...]
// - second arg: [ z,w, ... 7 more pairs of 8-bit values ...]
// and returns 8 16-bit values: [ x*z + y*w, ... 7 more 16-bit values ... ].
//
// That's why we go to all this trouble to make interlaced_x_weights,
// and here we're interlacing A0 with A1, B0 with B1 to match.
__m128i interlaced_A = _mm_unpacklo_epi8(_mm_cvtsi32_si128(A0), _mm_cvtsi32_si128(A1)),
interlaced_B = _mm_unpacklo_epi8(_mm_cvtsi32_si128(B0), _mm_cvtsi32_si128(B1));
return _mm_maddubs_epi16(_mm_unpacklo_epi64(interlaced_A, interlaced_B),
interlaced_x_weights);
}
// Interpolate {A0..A3} --> output pixel A, and {B0..B3} --> output pixel B.
// Returns two pixels, with each channel in a 16-bit lane of the __m128i.
static inline __m128i interpolate_in_x_and_y(uint32_t A0, uint32_t A1,
uint32_t A2, uint32_t A3,
uint32_t B0, uint32_t B1,
uint32_t B2, uint32_t B3,
const __m128i& interlaced_x_weights,
int wy) {
// The stored Y weight wy is for y1, and y0 gets a weight 16-wy.
const __m128i wy1 = _mm_set1_epi16(wy),
wy0 = _mm_sub_epi16(_mm_set1_epi16(16), wy1);
// First interpolate in X,
// leaving the values in 16-bit lanes scaled up by those [0,16] interlaced_x_weights.
__m128i row0 = interpolate_in_x(A0,A1, B0,B1, interlaced_x_weights),
row1 = interpolate_in_x(A2,A3, B2,B3, interlaced_x_weights);
// Interpolate in Y across the two rows,
// then scale everything down by the maximum total weight 16x16 = 256.
return _mm_srli_epi16(_mm_add_epi16(_mm_mullo_epi16(row0, wy0),
_mm_mullo_epi16(row1, wy1)), 8);
}
/*not static*/ inline
void S32_alpha_D32_filter_DX(const SkBitmapProcState& s,
const uint32_t* xy, int count, uint32_t* colors) {
SkASSERT(count > 0 && colors != nullptr);
SkASSERT(s.fFilterQuality != kNone_SkFilterQuality);
SkASSERT(kN32_SkColorType == s.fPixmap.colorType());
int alpha = s.fAlphaScale;
// Return (px * s.fAlphaScale) / 256. (s.fAlphaScale is in [0,256].)
auto scale_by_alpha = [alpha](const __m128i& px) {
return alpha == 256 ? px
: _mm_srli_epi16(_mm_mullo_epi16(px, _mm_set1_epi16(alpha)), 8);
};
// We're in _DX_ mode here, so we're only varying in X.
// That means the first entry of xy is our constant pair of Y coordinates and weight in Y.
// All the other entries in xy will be pairs of X coordinates and the X weight.
int y0, y1, wy;
decode_packed_coordinates_and_weight(*xy++, &y0, &y1, &wy);
auto row0 = (const uint32_t*)((const uint8_t*)s.fPixmap.addr() + y0 * s.fPixmap.rowBytes()),
row1 = (const uint32_t*)((const uint8_t*)s.fPixmap.addr() + y1 * s.fPixmap.rowBytes());
while (count >= 4) {
// We can really get going, loading 4 X pairs at a time to produce 4 output pixels.
const __m128i xx = _mm_loadu_si128((const __m128i*)xy);
int x0[4],
x1[4];
__m128i wx;
decode_packed_coordinates_and_weight(xx, x0, x1, &wx);
// Splat out each x weight wx four times (one for each pixel channel) as wx1,
// and sixteen minus that as the weight for x0, wx0.
__m128i wx1 = _mm_shuffle_epi8(wx, _mm_setr_epi8(0,0,0,0,4,4,4,4,8,8,8,8,12,12,12,12)),
wx0 = _mm_sub_epi8(_mm_set1_epi8(16), wx1);
// We need to interlace wx0 and wx1 for _mm_maddubs_epi16().
__m128i interlaced_x_weights_AB = _mm_unpacklo_epi8(wx0,wx1),
interlaced_x_weights_CD = _mm_unpackhi_epi8(wx0,wx1);
// interpolate_in_x_and_y() can produce two output pixels (A and B) at a time
// from eight input pixels {A0..A3} and {B0..B3}, arranged in a 2x2 grid for each.
__m128i AB = interpolate_in_x_and_y(row0[x0[0]], row0[x1[0]],
row1[x0[0]], row1[x1[0]],
row0[x0[1]], row0[x1[1]],
row1[x0[1]], row1[x1[1]],
interlaced_x_weights_AB, wy);
// Once more with the other half of the x-weights for two more pixels C,D.
__m128i CD = interpolate_in_x_and_y(row0[x0[2]], row0[x1[2]],
row1[x0[2]], row1[x1[2]],
row0[x0[3]], row0[x1[3]],
row1[x0[3]], row1[x1[3]],
interlaced_x_weights_CD, wy);
// Scale by alpha, pack back together to 8-bit lanes, and write out four pixels!
_mm_storeu_si128((__m128i*)colors, _mm_packus_epi16(scale_by_alpha(AB),
scale_by_alpha(CD)));
xy += 4;
colors += 4;
count -= 4;
}
while (count --> 0) {
// This is exactly the same flow as the count >= 4 loop above, but writing one pixel.
int x0, x1, wx;
decode_packed_coordinates_and_weight(*xy++, &x0, &x1, &wx);
// As above, splat out wx four times as wx1, and sixteen minus that as wx0.
__m128i wx1 = _mm_set1_epi8(wx), // This splats it out 16 times, but that's fine.
wx0 = _mm_sub_epi8(_mm_set1_epi8(16), wx1);
__m128i interlaced_x_weights_A = _mm_unpacklo_epi8(wx0, wx1);
__m128i A = interpolate_in_x_and_y(row0[x0], row0[x1],
row1[x0], row1[x1],
0, 0,
0, 0,
interlaced_x_weights_A, wy);
*colors++ = _mm_cvtsi128_si32(_mm_packus_epi16(scale_by_alpha(A), _mm_setzero_si128()));
}
}
#elif 1 && SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
// TODO(mtklein): clean up this code, use decode_packed_coordinates_and_weight(), etc.
/*not static*/ inline
void S32_alpha_D32_filter_DX(const SkBitmapProcState& s,
const uint32_t* xy, int count, uint32_t* colors) {
SkASSERT(count > 0 && colors != nullptr);
SkASSERT(s.fFilterQuality != kNone_SkFilterQuality);
SkASSERT(kN32_SkColorType == s.fPixmap.colorType());
SkASSERT(s.fAlphaScale <= 256);
int y0, y1, wy;
decode_packed_coordinates_and_weight(*xy++, &y0, &y1, &wy);
auto row0 = (const uint32_t*)( (const char*)s.fPixmap.addr() + y0 * s.fPixmap.rowBytes() ),
row1 = (const uint32_t*)( (const char*)s.fPixmap.addr() + y1 * s.fPixmap.rowBytes() );
// We'll put one pixel in the low 4 16-bit lanes to line up with wy,
// and another in the upper 4 16-bit lanes to line up with 16 - wy.
const __m128i allY = _mm_unpacklo_epi64(_mm_set1_epi16( wy),
_mm_set1_epi16(16-wy));
while (count --> 0) {
int x0, x1, wx;
decode_packed_coordinates_and_weight(*xy++, &x0, &x1, &wx);
// Load the 4 pixels we're interpolating.
const __m128i a00 = _mm_cvtsi32_si128(row0[x0]),
a01 = _mm_cvtsi32_si128(row0[x1]),
a10 = _mm_cvtsi32_si128(row1[x0]),
a11 = _mm_cvtsi32_si128(row1[x1]);
// Line up low-x pixels a00 and a10 with allY.
__m128i a00a10 = _mm_unpacklo_epi8(_mm_unpacklo_epi32(a10, a00),
_mm_setzero_si128());
// Scale by allY and 16-wx.
a00a10 = _mm_mullo_epi16(a00a10, allY);
a00a10 = _mm_mullo_epi16(a00a10, _mm_set1_epi16(16-wx));
// Line up high-x pixels a01 and a11 with allY.
__m128i a01a11 = _mm_unpacklo_epi8(_mm_unpacklo_epi32(a11, a01),
_mm_setzero_si128());
// Scale by allY and wx.
a01a11 = _mm_mullo_epi16(a01a11, allY);
a01a11 = _mm_mullo_epi16(a01a11, _mm_set1_epi16(wx));
// Add the two intermediates, summing across in one direction.
__m128i halves = _mm_add_epi16(a00a10, a01a11);
// Add the two halves to each other to sum in the other direction.
__m128i sum = _mm_add_epi16(halves, _mm_srli_si128(halves, 8));
// Get back to [0,255] by dividing by maximum weight 16x16 = 256.
sum = _mm_srli_epi16(sum, 8);
if (s.fAlphaScale < 256) {
// Scale by alpha, which is in [0,256].
sum = _mm_mullo_epi16(sum, _mm_set1_epi16(s.fAlphaScale));
sum = _mm_srli_epi16(sum, 8);
}
// Pack back into 8-bit values and store.
*colors++ = _mm_cvtsi128_si32(_mm_packus_epi16(sum, _mm_setzero_si128()));
}
}
#else
// The NEON code only actually differs from the portable code in the
// filtering step after we've loaded all four pixels we want to bilerp.
#if defined(SK_ARM_HAS_NEON)
static void filter_and_scale_by_alpha(unsigned x, unsigned y,
SkPMColor a00, SkPMColor a01,
SkPMColor a10, SkPMColor a11,
SkPMColor *dst,
uint16_t scale) {
uint8x8_t vy, vconst16_8, v16_y, vres;
uint16x4_t vx, vconst16_16, v16_x, tmp, vscale;
uint32x2_t va0, va1;
uint16x8_t tmp1, tmp2;
vy = vdup_n_u8(y); // duplicate y into vy
vconst16_8 = vmov_n_u8(16); // set up constant in vconst16_8
v16_y = vsub_u8(vconst16_8, vy); // v16_y = 16-y
va0 = vdup_n_u32(a00); // duplicate a00
va1 = vdup_n_u32(a10); // duplicate a10
va0 = vset_lane_u32(a01, va0, 1); // set top to a01
va1 = vset_lane_u32(a11, va1, 1); // set top to a11
tmp1 = vmull_u8(vreinterpret_u8_u32(va0), v16_y); // tmp1 = [a01|a00] * (16-y)
tmp2 = vmull_u8(vreinterpret_u8_u32(va1), vy); // tmp2 = [a11|a10] * y
vx = vdup_n_u16(x); // duplicate x into vx
vconst16_16 = vmov_n_u16(16); // set up constant in vconst16_16
v16_x = vsub_u16(vconst16_16, vx); // v16_x = 16-x
tmp = vmul_u16(vget_high_u16(tmp1), vx); // tmp = a01 * x
tmp = vmla_u16(tmp, vget_high_u16(tmp2), vx); // tmp += a11 * x
tmp = vmla_u16(tmp, vget_low_u16(tmp1), v16_x); // tmp += a00 * (16-x)
tmp = vmla_u16(tmp, vget_low_u16(tmp2), v16_x); // tmp += a10 * (16-x)
if (scale < 256) {
vscale = vdup_n_u16(scale); // duplicate scale
tmp = vshr_n_u16(tmp, 8); // shift down result by 8
tmp = vmul_u16(tmp, vscale); // multiply result by scale
}
vres = vshrn_n_u16(vcombine_u16(tmp, vcreate_u16(0)), 8); // shift down result by 8
vst1_lane_u32(dst, vreinterpret_u32_u8(vres), 0); // store result
}
#else
static void filter_and_scale_by_alpha(unsigned x, unsigned y,
SkPMColor a00, SkPMColor a01,
SkPMColor a10, SkPMColor a11,
SkPMColor* dstColor,
unsigned alphaScale) {
SkASSERT((unsigned)x <= 0xF);
SkASSERT((unsigned)y <= 0xF);
SkASSERT(alphaScale <= 256);
int xy = x * y;
const uint32_t mask = 0xFF00FF;
int scale = 256 - 16*y - 16*x + xy;
uint32_t lo = (a00 & mask) * scale;
uint32_t hi = ((a00 >> 8) & mask) * scale;
scale = 16*x - xy;
lo += (a01 & mask) * scale;
hi += ((a01 >> 8) & mask) * scale;
scale = 16*y - xy;
lo += (a10 & mask) * scale;
hi += ((a10 >> 8) & mask) * scale;
lo += (a11 & mask) * xy;
hi += ((a11 >> 8) & mask) * xy;
if (alphaScale < 256) {
lo = ((lo >> 8) & mask) * alphaScale;
hi = ((hi >> 8) & mask) * alphaScale;
}
*dstColor = ((lo >> 8) & mask) | (hi & ~mask);
}
#endif
/*not static*/ inline
void S32_alpha_D32_filter_DX(const SkBitmapProcState& s,
const uint32_t* xy, int count, SkPMColor* colors) {
SkASSERT(count > 0 && colors != nullptr);
SkASSERT(s.fFilterQuality != kNone_SkFilterQuality);
SkASSERT(4 == s.fPixmap.info().bytesPerPixel());
SkASSERT(s.fAlphaScale <= 256);
int y0, y1, wy;
decode_packed_coordinates_and_weight(*xy++, &y0, &y1, &wy);
auto row0 = (const uint32_t*)( (const char*)s.fPixmap.addr() + y0 * s.fPixmap.rowBytes() ),
row1 = (const uint32_t*)( (const char*)s.fPixmap.addr() + y1 * s.fPixmap.rowBytes() );
while (count --> 0) {
int x0, x1, wx;
decode_packed_coordinates_and_weight(*xy++, &x0, &x1, &wx);
filter_and_scale_by_alpha(wx, wy,
row0[x0], row0[x1],
row1[x0], row1[x1],
colors++,
s.fAlphaScale);
}
}
#endif
} // namespace SK_OPTS_NS
#endif