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Unified Diff: src/opts/SkBlitRow_opts_SSE2.cpp

Issue 17847010: Commented SSE blend functions and cleaned-up variable naming. (Closed) Base URL: https://skia.googlecode.com/svn/trunk
Patch Set: Fixed missing variable rename. Created 7 years, 6 months ago
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Index: src/opts/SkBlitRow_opts_SSE2.cpp
diff --git a/src/opts/SkBlitRow_opts_SSE2.cpp b/src/opts/SkBlitRow_opts_SSE2.cpp
index 27ce1e5f62851bcd2f210f3f692ac74a070a77ba..f3d010e3bc4502f1c54d4cb9b09488c6494a1a98 100644
--- a/src/opts/SkBlitRow_opts_SSE2.cpp
+++ b/src/opts/SkBlitRow_opts_SSE2.cpp
@@ -544,149 +544,232 @@ void SkARGB32_A8_BlitMask_SSE2(void* device, size_t dstRB, const void* maskPtr,
#define SkPackedB16x5ToUnmaskedB32x5_SSE2(x) (_mm_srli_epi32(x, -SK_B16x5_B32x5_SHIFT))
#endif
-static __m128i SkBlendLCD16_SSE2(__m128i &srci, __m128i &dst,
- __m128i &mask, __m128i &scale) {
+static __m128i SkBlendLCD16_SSE2(__m128i &src, __m128i &dst,
+ __m128i &mask, __m128i &srcA) {
+ // In the following comments, the components of src, dst and mask are
+ // abbreviated as (s)rc, (d)st, and (m)ask. Color components are marked
+ // by an R, G, B, or A suffix. Components of one of the four pixels that
+ // are processed in parallel are marked with 0, 1, 2, and 3. "d1B", for
+ // example is the blue channel of the second destination pixel. Memory
+ // layout is shown for an ARGB byte order in a color value.
+
+ // src and srcA store 8-bit values interleaved with zeros.
+ // src = (0xFF, 0, sR, 0, sG, 0, sB, 0, 0xFF, 0, sR, 0, sG, 0, sB, 0)
+ // srcA = (srcA, 0, srcA, 0, srcA, 0, srcA, 0,
+ // srcA, 0, srcA, 0, srcA, 0, srcA, 0)
+ // mask stores 16-bit values (compressed three channels) interleaved with zeros.
+ // Lo and Hi denote the low and high bytes of a 16-bit value, respectively.
+ // mask = (m0RGBLo, m0RGBHi, 0, 0, m1RGBLo, m1RGBHi, 0, 0,
+ // m2RGBLo, m2RGBHi, 0, 0, m3RGBLo, m3RGBHi, 0, 0)
+
// Get the R,G,B of each 16bit mask pixel, we want all of them in 5 bits.
+ // r = (0, m0R, 0, 0, 0, m1R, 0, 0, 0, m2R, 0, 0, 0, m3R, 0, 0)
__m128i r = _mm_and_si128(SkPackedR16x5ToUnmaskedR32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_R32_SHIFT));
+ // g = (0, 0, m0G, 0, 0, 0, m1G, 0, 0, 0, m2G, 0, 0, 0, m3G, 0)
__m128i g = _mm_and_si128(SkPackedG16x5ToUnmaskedG32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_G32_SHIFT));
+ // b = (0, 0, 0, m0B, 0, 0, 0, m1B, 0, 0, 0, m2B, 0, 0, 0, m3B)
__m128i b = _mm_and_si128(SkPackedB16x5ToUnmaskedB32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_B32_SHIFT));
// Pack the 4 16bit mask pixels into 4 32bit pixels, (p0, p1, p2, p3)
+ // Each component (m0R, m0G, etc.) is then a 5-bit value aligned to an
+ // 8-bit position
+ // mask = (0, m0R, m0G, m0B, 0, m1R, m1G, m1B,
+ // 0, m2R, m2G, m2B, 0, m3R, m3G, m3B)
mask = _mm_or_si128(_mm_or_si128(r, g), b);
// Interleave R,G,B into the lower byte of word.
+ // i.e. split the sixteen 8-bit values from mask into two sets of eight
+ // 16-bit values, padded by zero.
__m128i maskLo, maskHi;
+ // maskLo = (0, 0, m0R, 0, m0G, 0, m0B, 0, 0, 0, m1R, 0, m1G, 0, m1B, 0)
maskLo = _mm_unpacklo_epi8(mask, _mm_setzero_si128());
+ // maskHi = (0, 0, m2R, 0, m2G, 0, m2B, 0, 0, 0, m3R, 0, m3G, 0, m3B, 0)
maskHi = _mm_unpackhi_epi8(mask, _mm_setzero_si128());
- // Upscale to 0..32
+ // Upscale from 0..31 to 0..32
+ // (allows to replace division by left-shift further down)
+ // Left-shift each component by 4 and add the result back to that component,
+ // mapping numbers in the range 0..15 to 0..15, and 16..31 to 17..32
maskLo = _mm_add_epi16(maskLo, _mm_srli_epi16(maskLo, 4));
maskHi = _mm_add_epi16(maskHi, _mm_srli_epi16(maskHi, 4));
- maskLo = _mm_mullo_epi16(maskLo, scale);
- maskHi = _mm_mullo_epi16(maskHi, scale);
+ // Multiply each component of maskLo and maskHi by srcA
+ maskLo = _mm_mullo_epi16(maskLo, srcA);
+ maskHi = _mm_mullo_epi16(maskHi, srcA);
+ // Left shift mask components by 8 (divide by 256)
maskLo = _mm_srli_epi16(maskLo, 8);
maskHi = _mm_srli_epi16(maskHi, 8);
- // Interleave R,G,B into the lower byte of the word.
+ // Interleave R,G,B into the lower byte of the word
+ // dstLo = (0, 0, d0R, 0, d0G, 0, d0B, 0, 0, 0, d1R, 0, d1G, 0, d1B, 0)
__m128i dstLo = _mm_unpacklo_epi8(dst, _mm_setzero_si128());
+ // dstLo = (0, 0, d2R, 0, d2G, 0, d2B, 0, 0, 0, d3R, 0, d3G, 0, d3B, 0)
__m128i dstHi = _mm_unpackhi_epi8(dst, _mm_setzero_si128());
- maskLo = _mm_mullo_epi16(maskLo, _mm_sub_epi16(srci, dstLo));
- maskHi = _mm_mullo_epi16(maskHi, _mm_sub_epi16(srci, dstHi));
+ // mask = (src - dst) * mask
+ maskLo = _mm_mullo_epi16(maskLo, _mm_sub_epi16(src, dstLo));
+ maskHi = _mm_mullo_epi16(maskHi, _mm_sub_epi16(src, dstHi));
+ // mask = (src - dst) * mask >> 5
maskLo = _mm_srai_epi16(maskLo, 5);
maskHi = _mm_srai_epi16(maskHi, 5);
// Add two pixels into result.
+ // result = dst + ((src - dst) * mask >> 5)
__m128i resultLo = _mm_add_epi16(dstLo, maskLo);
__m128i resultHi = _mm_add_epi16(dstHi, maskHi);
- // Pack into 4 32bit dst pixels
+ // Pack into 4 32bit dst pixels.
+ // resultLo and resultHi contain eight 16-bit components (two pixels) each.
+ // Merge into one SSE regsiter with sixteen 8-bit values (four pixels),
+ // clamping to 255 if necessary.
return _mm_packus_epi16(resultLo, resultHi);
}
-static __m128i SkBlendLCD16Opaque_SSE2(__m128i &srci, __m128i &dst,
+static __m128i SkBlendLCD16Opaque_SSE2(__m128i &src, __m128i &dst,
__m128i &mask) {
+ // In the following comments, the components of src, dst and mask are
+ // abbreviated as (s)rc, (d)st, and (m)ask. Color components are marked
+ // by an R, G, B, or A suffix. Components of one of the four pixels that
+ // are processed in parallel are marked with 0, 1, 2, and 3. "d1B", for
+ // example is the blue channel of the second destination pixel. Memory
+ // layout is shown for an ARGB byte order in a color value.
+
+ // src and srcA store 8-bit values interleaved with zeros.
+ // src = (0xFF, 0, sR, 0, sG, 0, sB, 0, 0xFF, 0, sR, 0, sG, 0, sB, 0)
+ // mask stores 16-bit values (shown as high and low bytes) interleaved with
+ // zeros
+ // mask = (m0RGBLo, m0RGBHi, 0, 0, m1RGBLo, m1RGBHi, 0, 0,
+ // m2RGBLo, m2RGBHi, 0, 0, m3RGBLo, m3RGBHi, 0, 0)
+
// Get the R,G,B of each 16bit mask pixel, we want all of them in 5 bits.
+ // r = (0, m0R, 0, 0, 0, m1R, 0, 0, 0, m2R, 0, 0, 0, m3R, 0, 0)
__m128i r = _mm_and_si128(SkPackedR16x5ToUnmaskedR32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_R32_SHIFT));
+ // g = (0, 0, m0G, 0, 0, 0, m1G, 0, 0, 0, m2G, 0, 0, 0, m3G, 0)
__m128i g = _mm_and_si128(SkPackedG16x5ToUnmaskedG32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_G32_SHIFT));
+ // b = (0, 0, 0, m0B, 0, 0, 0, m1B, 0, 0, 0, m2B, 0, 0, 0, m3B)
__m128i b = _mm_and_si128(SkPackedB16x5ToUnmaskedB32x5_SSE2(mask),
_mm_set1_epi32(0x1F << SK_B32_SHIFT));
// Pack the 4 16bit mask pixels into 4 32bit pixels, (p0, p1, p2, p3)
+ // Each component (m0R, m0G, etc.) is then a 5-bit value aligned to an
+ // 8-bit position
+ // mask = (0, m0R, m0G, m0B, 0, m1R, m1G, m1B,
+ // 0, m2R, m2G, m2B, 0, m3R, m3G, m3B)
mask = _mm_or_si128(_mm_or_si128(r, g), b);
// Interleave R,G,B into the lower byte of word.
+ // i.e. split the sixteen 8-bit values from mask into two sets of eight
+ // 16-bit values, padded by zero.
__m128i maskLo, maskHi;
+ // maskLo = (0, 0, m0R, 0, m0G, 0, m0B, 0, 0, 0, m1R, 0, m1G, 0, m1B, 0)
maskLo = _mm_unpacklo_epi8(mask, _mm_setzero_si128());
+ // maskHi = (0, 0, m2R, 0, m2G, 0, m2B, 0, 0, 0, m3R, 0, m3G, 0, m3B, 0)
maskHi = _mm_unpackhi_epi8(mask, _mm_setzero_si128());
- // Upscale to 0..32
+ // Upscale from 0..31 to 0..32
+ // (allows to replace division by left-shift further down)
+ // Left-shift each component by 4 and add the result back to that component,
+ // mapping numbers in the range 0..15 to 0..15, and 16..31 to 17..32
maskLo = _mm_add_epi16(maskLo, _mm_srli_epi16(maskLo, 4));
maskHi = _mm_add_epi16(maskHi, _mm_srli_epi16(maskHi, 4));
- // Interleave R,G,B into the lower byte of the word.
+ // Interleave R,G,B into the lower byte of the word
+ // dstLo = (0, 0, d0R, 0, d0G, 0, d0B, 0, 0, 0, d1R, 0, d1G, 0, d1B, 0)
__m128i dstLo = _mm_unpacklo_epi8(dst, _mm_setzero_si128());
+ // dstLo = (0, 0, d2R, 0, d2G, 0, d2B, 0, 0, 0, d3R, 0, d3G, 0, d3B, 0)
__m128i dstHi = _mm_unpackhi_epi8(dst, _mm_setzero_si128());
- maskLo = _mm_mullo_epi16(maskLo, _mm_sub_epi16(srci, dstLo));
- maskHi = _mm_mullo_epi16(maskHi, _mm_sub_epi16(srci, dstHi));
+ // mask = (src - dst) * mask
+ maskLo = _mm_mullo_epi16(maskLo, _mm_sub_epi16(src, dstLo));
+ maskHi = _mm_mullo_epi16(maskHi, _mm_sub_epi16(src, dstHi));
+ // mask = (src - dst) * mask >> 5
maskLo = _mm_srai_epi16(maskLo, 5);
maskHi = _mm_srai_epi16(maskHi, 5);
// Add two pixels into result.
+ // result = dst + ((src - dst) * mask >> 5)
__m128i resultLo = _mm_add_epi16(dstLo, maskLo);
__m128i resultHi = _mm_add_epi16(dstHi, maskHi);
// Pack into 4 32bit dst pixels and force opaque.
+ // resultLo and resultHi contain eight 16-bit components (two pixels) each.
+ // Merge into one SSE regsiter with sixteen 8-bit values (four pixels),
+ // clamping to 255 if necessary. Set alpha components to 0xFF.
return _mm_or_si128(_mm_packus_epi16(resultLo, resultHi),
_mm_set1_epi32(SK_A32_MASK << SK_A32_SHIFT));
}
-void SkBlitLCD16Row_SSE2(SkPMColor dst[], const uint16_t src[],
- SkColor color, int width, SkPMColor) {
+void SkBlitLCD16Row_SSE2(SkPMColor dst[], const uint16_t mask[],
+ SkColor src, int width, SkPMColor) {
if (width <= 0) {
return;
}
- int srcA = SkColorGetA(color);
- int srcR = SkColorGetR(color);
- int srcG = SkColorGetG(color);
- int srcB = SkColorGetB(color);
+ int srcA = SkColorGetA(src);
+ int srcR = SkColorGetR(src);
+ int srcG = SkColorGetG(src);
+ int srcB = SkColorGetB(src);
srcA = SkAlpha255To256(srcA);
if (width >= 4) {
SkASSERT(((size_t)dst & 0x03) == 0);
while (((size_t)dst & 0x0F) != 0) {
- *dst = SkBlendLCD16(srcA, srcR, srcG, srcB, *dst, *src);
- src++;
+ *dst = SkBlendLCD16(srcA, srcR, srcG, srcB, *dst, *mask);
+ mask++;
dst++;
width--;
}
__m128i *d = reinterpret_cast<__m128i*>(dst);
- __m128i srci = _mm_set1_epi32(SkPackARGB32(0xFF, srcR, srcG, srcB));
- srci = _mm_unpacklo_epi8(srci, _mm_setzero_si128());
- __m128i scale = _mm_set1_epi16(srcA);
+ // Set alpha to 0xFF and replicate source four times in SSE register.
+ __m128i src_sse = _mm_set1_epi32(SkPackARGB32(0xFF, srcR, srcG, srcB));
+ // Interleave with zeros to get two sets of four 16-bit values.
+ src_sse = _mm_unpacklo_epi8(src_sse, _mm_setzero_si128());
+ // Set srcA_sse to contain eight copies of srcA, padded with zero.
+ // src_sse=(0xFF, 0, sR, 0, sG, 0, sB, 0, 0xFF, 0, sR, 0, sG, 0, sB, 0)
+ __m128i srcA_sse = _mm_set1_epi16(srcA);
while (width >= 4) {
- __m128i dst_pixel = _mm_load_si128(d);
- __m128i mask_pixel = _mm_loadl_epi64(
- reinterpret_cast<const __m128i*>(src));
-
- // Check whether mask_pixels are equal to 0 and get the highest bit
- // of each byte of result, if mask pixes are all zero, we will get
+ // Load four destination pixels into dst_sse.
+ __m128i dst_sse = _mm_load_si128(d);
+ // Load four 16-bit masks into lower half of mask_sse.
+ __m128i mask_sse = _mm_loadl_epi64(
+ reinterpret_cast<const __m128i*>(mask));
+
+ // Check whether masks are equal to 0 and get the highest bit
+ // of each byte of result, if masks are all zero, we will get
// pack_cmp to 0xFFFF
- int pack_cmp = _mm_movemask_epi8(_mm_cmpeq_epi16(mask_pixel,
+ int pack_cmp = _mm_movemask_epi8(_mm_cmpeq_epi16(mask_sse,
_mm_setzero_si128()));
// if mask pixels are not all zero, we will blend the dst pixels
if (pack_cmp != 0xFFFF) {
// Unpack 4 16bit mask pixels to
- // (p0, 0, p1, 0, p2, 0, p3, 0)
- mask_pixel = _mm_unpacklo_epi16(mask_pixel,
- _mm_setzero_si128());
+ // mask_sse = (m0RGBLo, m0RGBHi, 0, 0, m1RGBLo, m1RGBHi, 0, 0,
+ // m2RGBLo, m2RGBHi, 0, 0, m3RGBLo, m3RGBHi, 0, 0)
+ mask_sse = _mm_unpacklo_epi16(mask_sse,
+ _mm_setzero_si128());
// Process 4 32bit dst pixels
- __m128i result = SkBlendLCD16_SSE2(srci, dst_pixel,
- mask_pixel, scale);
+ __m128i result = SkBlendLCD16_SSE2(src_sse, dst_sse,
+ mask_sse, srcA_sse);
_mm_store_si128(d, result);
}
d++;
- src += 4;
+ mask += 4;
width -= 4;
}
@@ -694,61 +777,67 @@ void SkBlitLCD16Row_SSE2(SkPMColor dst[], const uint16_t src[],
}
while (width > 0) {
- *dst = SkBlendLCD16(srcA, srcR, srcG, srcB, *dst, *src);
- src++;
+ *dst = SkBlendLCD16(srcA, srcR, srcG, srcB, *dst, *mask);
+ mask++;
dst++;
width--;
}
}
-void SkBlitLCD16OpaqueRow_SSE2(SkPMColor dst[], const uint16_t src[],
- SkColor color, int width, SkPMColor opaqueDst) {
+void SkBlitLCD16OpaqueRow_SSE2(SkPMColor dst[], const uint16_t mask[],
+ SkColor src, int width, SkPMColor opaqueDst) {
if (width <= 0) {
return;
}
- int srcR = SkColorGetR(color);
- int srcG = SkColorGetG(color);
- int srcB = SkColorGetB(color);
+ int srcR = SkColorGetR(src);
+ int srcG = SkColorGetG(src);
+ int srcB = SkColorGetB(src);
if (width >= 4) {
SkASSERT(((size_t)dst & 0x03) == 0);
while (((size_t)dst & 0x0F) != 0) {
- *dst = SkBlendLCD16Opaque(srcR, srcG, srcB, *dst, *src, opaqueDst);
- src++;
+ *dst = SkBlendLCD16Opaque(srcR, srcG, srcB, *dst, *mask, opaqueDst);
+ mask++;
dst++;
width--;
}
__m128i *d = reinterpret_cast<__m128i*>(dst);
- __m128i srci = _mm_set1_epi32(SkPackARGB32(0xFF, srcR, srcG, srcB));
- srci = _mm_unpacklo_epi8(srci, _mm_setzero_si128());
+ // Set alpha to 0xFF and replicate source four times in SSE register.
+ __m128i src_sse = _mm_set1_epi32(SkPackARGB32(0xFF, srcR, srcG, srcB));
+ // Set srcA_sse to contain eight copies of srcA, padded with zero.
+ // src_sse=(0xFF, 0, sR, 0, sG, 0, sB, 0, 0xFF, 0, sR, 0, sG, 0, sB, 0)
+ src_sse = _mm_unpacklo_epi8(src_sse, _mm_setzero_si128());
while (width >= 4) {
- __m128i dst_pixel = _mm_load_si128(d);
- __m128i mask_pixel = _mm_loadl_epi64(
- reinterpret_cast<const __m128i*>(src));
-
- // Check whether mask_pixels are equal to 0 and get the highest bit
- // of each byte of result, if mask pixes are all zero, we will get
+ // Load four destination pixels into dst_sse.
+ __m128i dst_sse = _mm_load_si128(d);
+ // Load four 16-bit masks into lower half of mask_sse.
+ __m128i mask_sse = _mm_loadl_epi64(
+ reinterpret_cast<const __m128i*>(mask));
+
+ // Check whether masks are equal to 0 and get the highest bit
+ // of each byte of result, if masks are all zero, we will get
// pack_cmp to 0xFFFF
- int pack_cmp = _mm_movemask_epi8(_mm_cmpeq_epi16(mask_pixel,
+ int pack_cmp = _mm_movemask_epi8(_mm_cmpeq_epi16(mask_sse,
_mm_setzero_si128()));
// if mask pixels are not all zero, we will blend the dst pixels
if (pack_cmp != 0xFFFF) {
// Unpack 4 16bit mask pixels to
- // (p0, 0, p1, 0, p2, 0, p3, 0)
- mask_pixel = _mm_unpacklo_epi16(mask_pixel,
- _mm_setzero_si128());
+ // mask_sse = (m0RGBLo, m0RGBHi, 0, 0, m1RGBLo, m1RGBHi, 0, 0,
+ // m2RGBLo, m2RGBHi, 0, 0, m3RGBLo, m3RGBHi, 0, 0)
+ mask_sse = _mm_unpacklo_epi16(mask_sse,
+ _mm_setzero_si128());
// Process 4 32bit dst pixels
- __m128i result = SkBlendLCD16Opaque_SSE2(srci, dst_pixel,
- mask_pixel);
+ __m128i result = SkBlendLCD16Opaque_SSE2(src_sse, dst_sse,
+ mask_sse);
_mm_store_si128(d, result);
}
d++;
- src += 4;
+ mask += 4;
width -= 4;
}
@@ -756,8 +845,8 @@ void SkBlitLCD16OpaqueRow_SSE2(SkPMColor dst[], const uint16_t src[],
}
while (width > 0) {
- *dst = SkBlendLCD16Opaque(srcR, srcG, srcB, *dst, *src, opaqueDst);
- src++;
+ *dst = SkBlendLCD16Opaque(srcR, srcG, srcB, *dst, *mask, opaqueDst);
+ mask++;
dst++;
width--;
}
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