src/core/SkBlitRow_D32.cpp - skia - Git at Google

 /*
  * 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 "include/private/SkColorData.h"
 #include "src/core/SkBlitRow.h"
 #include "src/core/SkOpts.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 < std::size(kProcs));
     flags &= std::size(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;
     }
     return SkOpts::blit_row_color32(dst, src, count, color);
 }
	/*
	* 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 "include/private/SkColorData.h"
	#include "src/core/SkBlitRow.h"
	#include "src/core/SkOpts.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 < std::size(kProcs));
	flags &= std::size(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;
	}
	return SkOpts::blit_row_color32(dst, src, count, color);
	}