93 lines
3.6 KiB
C
93 lines
3.6 KiB
C
// Copyright 2015 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// Utilities for processing transparent channel, SSE4.1 variant.
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#include "./dsp.h"
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#if defined(WEBP_USE_SSE41)
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#include <smmintrin.h>
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//------------------------------------------------------------------------------
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static int ExtractAlpha(const uint8_t* argb, int argb_stride,
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int width, int height,
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uint8_t* alpha, int alpha_stride) {
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// alpha_and stores an 'and' operation of all the alpha[] values. The final
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// value is not 0xff if any of the alpha[] is not equal to 0xff.
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uint32_t alpha_and = 0xff;
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int i, j;
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const __m128i all_0xff = _mm_set1_epi32(~0u);
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__m128i all_alphas = all_0xff;
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// We must be able to access 3 extra bytes after the last written byte
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// 'src[4 * width - 4]', because we don't know if alpha is the first or the
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// last byte of the quadruplet.
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const int limit = (width - 1) & ~15;
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const __m128i kCstAlpha0 = _mm_set_epi8(-1, -1, -1, -1, -1, -1, -1, -1,
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-1, -1, -1, -1, 12, 8, 4, 0);
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const __m128i kCstAlpha1 = _mm_set_epi8(-1, -1, -1, -1, -1, -1, -1, -1,
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12, 8, 4, 0, -1, -1, -1, -1);
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const __m128i kCstAlpha2 = _mm_set_epi8(-1, -1, -1, -1, 12, 8, 4, 0,
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-1, -1, -1, -1, -1, -1, -1, -1);
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const __m128i kCstAlpha3 = _mm_set_epi8(12, 8, 4, 0, -1, -1, -1, -1,
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-1, -1, -1, -1, -1, -1, -1, -1);
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for (j = 0; j < height; ++j) {
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const __m128i* src = (const __m128i*)argb;
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for (i = 0; i < limit; i += 16) {
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// load 64 argb bytes
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const __m128i a0 = _mm_loadu_si128(src + 0);
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const __m128i a1 = _mm_loadu_si128(src + 1);
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const __m128i a2 = _mm_loadu_si128(src + 2);
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const __m128i a3 = _mm_loadu_si128(src + 3);
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const __m128i b0 = _mm_shuffle_epi8(a0, kCstAlpha0);
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const __m128i b1 = _mm_shuffle_epi8(a1, kCstAlpha1);
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const __m128i b2 = _mm_shuffle_epi8(a2, kCstAlpha2);
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const __m128i b3 = _mm_shuffle_epi8(a3, kCstAlpha3);
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const __m128i c0 = _mm_or_si128(b0, b1);
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const __m128i c1 = _mm_or_si128(b2, b3);
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const __m128i d0 = _mm_or_si128(c0, c1);
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// store
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_mm_storeu_si128((__m128i*)&alpha[i], d0);
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// accumulate sixteen alpha 'and' in parallel
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all_alphas = _mm_and_si128(all_alphas, d0);
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src += 4;
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}
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for (; i < width; ++i) {
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const uint32_t alpha_value = argb[4 * i];
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alpha[i] = alpha_value;
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alpha_and &= alpha_value;
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}
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argb += argb_stride;
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alpha += alpha_stride;
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}
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// Combine the sixteen alpha 'and' into an 8-bit mask.
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alpha_and |= 0xff00u; // pretend the upper bits [8..15] were tested ok.
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alpha_and &= _mm_movemask_epi8(_mm_cmpeq_epi8(all_alphas, all_0xff));
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return (alpha_and == 0xffffu);
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}
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//------------------------------------------------------------------------------
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// Entry point
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extern void WebPInitAlphaProcessingSSE41(void);
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WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessingSSE41(void) {
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WebPExtractAlpha = ExtractAlpha;
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}
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#else // !WEBP_USE_SSE41
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WEBP_DSP_INIT_STUB(WebPInitAlphaProcessingSSE41)
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#endif // WEBP_USE_SSE41
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