/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Sk4px.h"
#include "SkBlitRow.h"
#include "SkColorData.h"
#include "SkOpts.h"
#include "SkUtils.h"
// Everyone agrees memcpy() is the best way to do this.
static void blit_row_s32_opaque(SkPMColor* dst,
const SkPMColor* src,
int count,
U8CPU alpha) {
SkASSERT(255 == alpha);
memcpy(dst, src, count * sizeof(SkPMColor));
}
// We have SSE2, NEON, and portable implementations of
// blit_row_s32_blend() and blit_row_s32a_blend().
// TODO(mtklein): can we do better in NEON than 2 pixels at a time?
#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
#include <emmintrin.h>
static inline __m128i SkPMLerp_SSE2(const __m128i& src,
const __m128i& dst,
const unsigned src_scale) {
// Computes dst + (((src - dst)*src_scale)>>8)
const __m128i mask = _mm_set1_epi32(0x00FF00FF);
// Unpack the 16x8-bit source into 2 8x16-bit splayed halves.
__m128i src_rb = _mm_and_si128(mask, src);
__m128i src_ag = _mm_srli_epi16(src, 8);
__m128i dst_rb = _mm_and_si128(mask, dst);
__m128i dst_ag = _mm_srli_epi16(dst, 8);
// Compute scaled differences.
__m128i diff_rb = _mm_sub_epi16(src_rb, dst_rb);
__m128i diff_ag = _mm_sub_epi16(src_ag, dst_ag);
__m128i s = _mm_set1_epi16(src_scale);
diff_rb = _mm_mullo_epi16(diff_rb, s);
diff_ag = _mm_mullo_epi16(diff_ag, s);
// Pack the differences back together.
diff_rb = _mm_srli_epi16(diff_rb, 8);
diff_ag = _mm_andnot_si128(mask, diff_ag);
__m128i diff = _mm_or_si128(diff_rb, diff_ag);
// Add difference to destination.
return _mm_add_epi8(dst, diff);
}
static void blit_row_s32_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha <= 255);
auto src4 = (const __m128i*)src;
auto dst4 = ( __m128i*)dst;
while (count >= 4) {
_mm_storeu_si128(dst4, SkPMLerp_SSE2(_mm_loadu_si128(src4),
_mm_loadu_si128(dst4),
SkAlpha255To256(alpha)));
src4++;
dst4++;
count -= 4;
}
src = (const SkPMColor*)src4;
dst = ( SkPMColor*)dst4;
while (count --> 0) {
*dst = SkPMLerp(*src, *dst, SkAlpha255To256(alpha));
src++;
dst++;
}
}
static inline __m128i SkBlendARGB32_SSE2(const __m128i& src,
const __m128i& dst,
const unsigned aa) {
unsigned alpha = SkAlpha255To256(aa);
__m128i src_scale = _mm_set1_epi16(alpha);
// SkAlphaMulInv256(SkGetPackedA32(src), src_scale)
__m128i dst_scale = _mm_srli_epi32(src, 24);
// High words in dst_scale are 0, so it's safe to multiply with 16-bit src_scale.
dst_scale = _mm_mullo_epi16(dst_scale, src_scale);
dst_scale = _mm_sub_epi32(_mm_set1_epi32(0xFFFF), dst_scale);
dst_scale = _mm_add_epi32(dst_scale, _mm_srli_epi32(dst_scale, 8));
dst_scale = _mm_srli_epi32(dst_scale, 8);
// Duplicate scales into 2x16-bit pattern per pixel.
dst_scale = _mm_shufflelo_epi16(dst_scale, _MM_SHUFFLE(2, 2, 0, 0));
dst_scale = _mm_shufflehi_epi16(dst_scale, _MM_SHUFFLE(2, 2, 0, 0));
const __m128i mask = _mm_set1_epi32(0x00FF00FF);
// Unpack the 16x8-bit source/destination into 2 8x16-bit splayed halves.
__m128i src_rb = _mm_and_si128(mask, src);
__m128i src_ag = _mm_srli_epi16(src, 8);
__m128i dst_rb = _mm_and_si128(mask, dst);
__m128i dst_ag = _mm_srli_epi16(dst, 8);
// Scale them.
src_rb = _mm_mullo_epi16(src_rb, src_scale);
src_ag = _mm_mullo_epi16(src_ag, src_scale);
dst_rb = _mm_mullo_epi16(dst_rb, dst_scale);
dst_ag = _mm_mullo_epi16(dst_ag, dst_scale);
// Add the scaled source and destination.
dst_rb = _mm_add_epi16(src_rb, dst_rb);
dst_ag = _mm_add_epi16(src_ag, dst_ag);
// Unsplay the halves back together.
dst_rb = _mm_srli_epi16(dst_rb, 8);
dst_ag = _mm_andnot_si128(mask, dst_ag);
return _mm_or_si128(dst_rb, dst_ag);
}
static void blit_row_s32a_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha <= 255);
auto src4 = (const __m128i*)src;
auto dst4 = ( __m128i*)dst;
while (count >= 4) {
_mm_storeu_si128(dst4, SkBlendARGB32_SSE2(_mm_loadu_si128(src4),
_mm_loadu_si128(dst4),
alpha));
src4++;
dst4++;
count -= 4;
}
src = (const SkPMColor*)src4;
dst = ( SkPMColor*)dst4;
while (count --> 0) {
*dst = SkBlendARGB32(*src, *dst, alpha);
src++;
dst++;
}
}
#elif defined(SK_ARM_HAS_NEON)
#include <arm_neon.h>
static void blit_row_s32_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha <= 255);
uint16_t src_scale = SkAlpha255To256(alpha);
uint16_t dst_scale = 256 - src_scale;
while (count >= 2) {
uint8x8_t vsrc, vdst, vres;
uint16x8_t vsrc_wide, vdst_wide;
vsrc = vreinterpret_u8_u32(vld1_u32(src));
vdst = vreinterpret_u8_u32(vld1_u32(dst));
vsrc_wide = vmovl_u8(vsrc);
vsrc_wide = vmulq_u16(vsrc_wide, vdupq_n_u16(src_scale));
vdst_wide = vmull_u8(vdst, vdup_n_u8(dst_scale));
vdst_wide += vsrc_wide;
vres = vshrn_n_u16(vdst_wide, 8);
vst1_u32(dst, vreinterpret_u32_u8(vres));
src += 2;
dst += 2;
count -= 2;
}
if (count == 1) {
uint8x8_t vsrc = vdup_n_u8(0), vdst = vdup_n_u8(0), vres;
uint16x8_t vsrc_wide, vdst_wide;
vsrc = vreinterpret_u8_u32(vld1_lane_u32(src, vreinterpret_u32_u8(vsrc), 0));
vdst = vreinterpret_u8_u32(vld1_lane_u32(dst, vreinterpret_u32_u8(vdst), 0));
vsrc_wide = vmovl_u8(vsrc);
vsrc_wide = vmulq_u16(vsrc_wide, vdupq_n_u16(src_scale));
vdst_wide = vmull_u8(vdst, vdup_n_u8(dst_scale));
vdst_wide += vsrc_wide;
vres = vshrn_n_u16(vdst_wide, 8);
vst1_lane_u32(dst, vreinterpret_u32_u8(vres), 0);
}
}
static void blit_row_s32a_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha < 255);
unsigned alpha256 = SkAlpha255To256(alpha);
if (count & 1) {
uint8x8_t vsrc = vdup_n_u8(0), vdst = vdup_n_u8(0), vres;
uint16x8_t vdst_wide, vsrc_wide;
unsigned dst_scale;
vsrc = vreinterpret_u8_u32(vld1_lane_u32(src, vreinterpret_u32_u8(vsrc), 0));
vdst = vreinterpret_u8_u32(vld1_lane_u32(dst, vreinterpret_u32_u8(vdst), 0));
dst_scale = vget_lane_u8(vsrc, 3);
dst_scale = SkAlphaMulInv256(dst_scale, alpha256);
vsrc_wide = vmovl_u8(vsrc);
vsrc_wide = vmulq_n_u16(vsrc_wide, alpha256);
vdst_wide = vmovl_u8(vdst);
vdst_wide = vmulq_n_u16(vdst_wide, dst_scale);
vdst_wide += vsrc_wide;
vres = vshrn_n_u16(vdst_wide, 8);
vst1_lane_u32(dst, vreinterpret_u32_u8(vres), 0);
dst++;
src++;
count--;
}
uint8x8_t alpha_mask;
static const uint8_t alpha_mask_setup[] = {3,3,3,3,7,7,7,7};
alpha_mask = vld1_u8(alpha_mask_setup);
while (count) {
uint8x8_t vsrc, vdst, vres, vsrc_alphas;
uint16x8_t vdst_wide, vsrc_wide, vsrc_scale, vdst_scale;
__builtin_prefetch(src+32);
__builtin_prefetch(dst+32);
vsrc = vreinterpret_u8_u32(vld1_u32(src));
vdst = vreinterpret_u8_u32(vld1_u32(dst));
vsrc_scale = vdupq_n_u16(alpha256);
vsrc_alphas = vtbl1_u8(vsrc, alpha_mask);
vdst_scale = vmovl_u8(vsrc_alphas);
// Calculate SkAlphaMulInv256(vdst_scale, vsrc_scale).
// A 16-bit lane would overflow if we used 0xFFFF here,
// so use an approximation with 0xFF00 that is off by 1,
// and add back 1 after to get the correct value.
// This is valid if alpha256 <= 255.
vdst_scale = vmlsq_u16(vdupq_n_u16(0xFF00), vdst_scale, vsrc_scale);
vdst_scale = vsraq_n_u16(vdst_scale, vdst_scale, 8);
vdst_scale = vsraq_n_u16(vdupq_n_u16(1), vdst_scale, 8);
vsrc_wide = vmovl_u8(vsrc);
vsrc_wide *= vsrc_scale;
vdst_wide = vmovl_u8(vdst);
vdst_wide *= vdst_scale;
vdst_wide += vsrc_wide;
vres = vshrn_n_u16(vdst_wide, 8);
vst1_u32(dst, vreinterpret_u32_u8(vres));
src += 2;
dst += 2;
count -= 2;
}
}
#else
static void blit_row_s32_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha <= 255);
while (count --> 0) {
*dst = SkPMLerp(*src, *dst, SkAlpha255To256(alpha));
src++;
dst++;
}
}
static void blit_row_s32a_blend(SkPMColor* dst, const SkPMColor* src, int count, U8CPU alpha) {
SkASSERT(alpha <= 255);
while (count --> 0) {
*dst = SkBlendARGB32(*src, *dst, alpha);
src++;
dst++;
}
}
#endif
SkBlitRow::Proc32 SkBlitRow::Factory32(unsigned flags) {
static const SkBlitRow::Proc32 kProcs[] = {
blit_row_s32_opaque,
blit_row_s32_blend,
nullptr, // blit_row_s32a_opaque is in SkOpts
blit_row_s32a_blend
};
SkASSERT(flags < SK_ARRAY_COUNT(kProcs));
flags &= SK_ARRAY_COUNT(kProcs) - 1; // just to be safe
return flags == 2 ? SkOpts::blit_row_s32a_opaque
: kProcs[flags];
}
void SkBlitRow::Color32(SkPMColor dst[], const SkPMColor src[], int count, SkPMColor color) {
switch (SkGetPackedA32(color)) {
case 0: memmove(dst, src, count * sizeof(SkPMColor)); return;
case 255: sk_memset32(dst, color, count); return;
}
unsigned invA = 255 - SkGetPackedA32(color);
invA += invA >> 7;
SkASSERT(invA < 256); // We've should have already handled alpha == 0 externally.
Sk16h colorHighAndRound = (Sk4px::DupPMColor(color).widen() << 8) + Sk16h(128);
Sk16b invA_16x(invA);
Sk4px::MapSrc(count, dst, src, [&](const Sk4px& src4) -> Sk4px {
return (src4 * invA_16x).addNarrowHi(colorHighAndRound);
});
}