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SSE2 implementation of HasAlphaXXX

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Change-Id: I2548d9a0c252e20ee3cf5f4be736a3703671ecb4
HasAlpha32b: ~3-4x faster
HasAlpha8b: ~7-8x faster
This commit is contained in:
Pascal Massimino 2017-11-23 13:38:20 +01:00
parent b299c47eac
commit a80c46bd87
1 changed files with 58 additions and 0 deletions
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58
src/dsp/alpha_processing_sse2.c
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@ -210,6 +210,61 @@ static void ApplyAlphaMultiply_SSE2(uint8_t* rgba, int alpha_first,
#undef MULTIPLIER
#undef PREMULTIPLY
//------------------------------------------------------------------------------
// Alpha detection
static int HasAlpha8b_SSE2(const uint8_t* src, int length) {
const __m128i all_0xff = _mm_set1_epi8(0xff);
int i = 0;
for (; i + 16 <= length; i += 16) {
const __m128i v = _mm_loadu_si128((const __m128i*)(src + i));
const __m128i bits = _mm_cmpeq_epi8(v, all_0xff);
const int mask = _mm_movemask_epi8(bits);
if (mask != 0xffff) return 1;
}
for (; i < length; ++i) if (src[i] != 0xff) return 1;
return 0;
}
static int HasAlpha32b_SSE2(const uint8_t* src, int length) {
const __m128i alpha_mask = _mm_set1_epi32(0xff);
const __m128i all_0xff = _mm_set1_epi8(0xff);
int i = 0;
// We don't know if we can access the last 3 bytes after the last alpha
// value 'src[4 * length - 4]' (because we don't know if alpha is the first
// or the last byte of the quadruplet). Hence the '-3' protection below.
length = length * 4 - 3; // size in bytes
for (; i + 64 <= length; i += 64) {
const __m128i a0 = _mm_loadu_si128((const __m128i*)(src + i + 0));
const __m128i a1 = _mm_loadu_si128((const __m128i*)(src + i + 16));
const __m128i a2 = _mm_loadu_si128((const __m128i*)(src + i + 32));
const __m128i a3 = _mm_loadu_si128((const __m128i*)(src + i + 48));
const __m128i b0 = _mm_and_si128(a0, alpha_mask);
const __m128i b1 = _mm_and_si128(a1, alpha_mask);
const __m128i b2 = _mm_and_si128(a2, alpha_mask);
const __m128i b3 = _mm_and_si128(a3, alpha_mask);
const __m128i c0 = _mm_packs_epi32(b0, b1);
const __m128i c1 = _mm_packs_epi32(b2, b3);
const __m128i d = _mm_packus_epi16(c0, c1);
const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);
const int mask = _mm_movemask_epi8(bits);
if (mask != 0xffff) return 1;
}
for (; i + 32 <= length; i += 32) {
const __m128i a0 = _mm_loadu_si128((const __m128i*)(src + i + 0));
const __m128i a1 = _mm_loadu_si128((const __m128i*)(src + i + 16));
const __m128i b0 = _mm_and_si128(a0, alpha_mask);
const __m128i b1 = _mm_and_si128(a1, alpha_mask);
const __m128i c = _mm_packs_epi32(b0, b1);
const __m128i d = _mm_packus_epi16(c, c);
const __m128i bits = _mm_cmpeq_epi8(d, all_0xff);
const int mask = _mm_movemask_epi8(bits);
if (mask != 0xffff) return 1;
}
for (; i <= length; i += 4) if (src[i] != 0xff) return 1;
return 0;
}
// -----------------------------------------------------------------------------
// Apply alpha value to rows
@ -276,6 +331,9 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE2(void) {
WebPDispatchAlpha = DispatchAlpha_SSE2;
WebPDispatchAlphaToGreen = DispatchAlphaToGreen_SSE2;
WebPExtractAlpha = ExtractAlpha_SSE2;
WebPHasAlpha8b = HasAlpha8b_SSE2;
WebPHasAlpha32b = HasAlpha32b_SSE2;
}
#else // !WEBP_USE_SSE2