1 // Copyright 2015 Google Inc. All Rights Reserved. 2 // 3 // Use of this source code is governed by a BSD-style license 4 // that can be found in the COPYING file in the root of the source 5 // tree. An additional intellectual property rights grant can be found 6 // in the file PATENTS. All contributing project authors may 7 // be found in the AUTHORS file in the root of the source tree. 8 // ----------------------------------------------------------------------------- 9 // 10 // SSE2 version of cost functions 11 // 12 // Author: Skal (pascal.massimino (at) gmail.com) 13 14 #include "./dsp.h" 15 16 #if defined(WEBP_USE_SSE2) 17 #include <emmintrin.h> 18 19 #include "../enc/cost_enc.h" 20 #include "../enc/vp8i_enc.h" 21 #include "../utils/utils.h" 22 23 //------------------------------------------------------------------------------ 24 25 static void SetResidualCoeffsSSE2(const int16_t* const coeffs, 26 VP8Residual* const res) { 27 const __m128i c0 = _mm_loadu_si128((const __m128i*)(coeffs + 0)); 28 const __m128i c1 = _mm_loadu_si128((const __m128i*)(coeffs + 8)); 29 // Use SSE2 to compare 16 values with a single instruction. 30 const __m128i zero = _mm_setzero_si128(); 31 const __m128i m0 = _mm_packs_epi16(c0, c1); 32 const __m128i m1 = _mm_cmpeq_epi8(m0, zero); 33 // Get the comparison results as a bitmask into 16bits. Negate the mask to get 34 // the position of entries that are not equal to zero. We don't need to mask 35 // out least significant bits according to res->first, since coeffs[0] is 0 36 // if res->first > 0. 37 const uint32_t mask = 0x0000ffffu ^ (uint32_t)_mm_movemask_epi8(m1); 38 // The position of the most significant non-zero bit indicates the position of 39 // the last non-zero value. 40 assert(res->first == 0 || coeffs[0] == 0); 41 res->last = mask ? BitsLog2Floor(mask) : -1; 42 res->coeffs = coeffs; 43 } 44 45 static int GetResidualCostSSE2(int ctx0, const VP8Residual* const res) { 46 uint8_t levels[16], ctxs[16]; 47 uint16_t abs_levels[16]; 48 int n = res->first; 49 // should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1 50 const int p0 = res->prob[n][ctx0][0]; 51 CostArrayPtr const costs = res->costs; 52 const uint16_t* t = costs[n][ctx0]; 53 // bit_cost(1, p0) is already incorporated in t[] tables, but only if ctx != 0 54 // (as required by the syntax). For ctx0 == 0, we need to add it here or it'll 55 // be missing during the loop. 56 int cost = (ctx0 == 0) ? VP8BitCost(1, p0) : 0; 57 58 if (res->last < 0) { 59 return VP8BitCost(0, p0); 60 } 61 62 { // precompute clamped levels and contexts, packed to 8b. 63 const __m128i zero = _mm_setzero_si128(); 64 const __m128i kCst2 = _mm_set1_epi8(2); 65 const __m128i kCst67 = _mm_set1_epi8(MAX_VARIABLE_LEVEL); 66 const __m128i c0 = _mm_loadu_si128((const __m128i*)&res->coeffs[0]); 67 const __m128i c1 = _mm_loadu_si128((const __m128i*)&res->coeffs[8]); 68 const __m128i D0 = _mm_sub_epi16(zero, c0); 69 const __m128i D1 = _mm_sub_epi16(zero, c1); 70 const __m128i E0 = _mm_max_epi16(c0, D0); // abs(v), 16b 71 const __m128i E1 = _mm_max_epi16(c1, D1); 72 const __m128i F = _mm_packs_epi16(E0, E1); 73 const __m128i G = _mm_min_epu8(F, kCst2); // context = 0,1,2 74 const __m128i H = _mm_min_epu8(F, kCst67); // clamp_level in [0..67] 75 76 _mm_storeu_si128((__m128i*)&ctxs[0], G); 77 _mm_storeu_si128((__m128i*)&levels[0], H); 78 79 _mm_storeu_si128((__m128i*)&abs_levels[0], E0); 80 _mm_storeu_si128((__m128i*)&abs_levels[8], E1); 81 } 82 for (; n < res->last; ++n) { 83 const int ctx = ctxs[n]; 84 const int level = levels[n]; 85 const int flevel = abs_levels[n]; // full level 86 cost += VP8LevelFixedCosts[flevel] + t[level]; // simplified VP8LevelCost() 87 t = costs[n + 1][ctx]; 88 } 89 // Last coefficient is always non-zero 90 { 91 const int level = levels[n]; 92 const int flevel = abs_levels[n]; 93 assert(flevel != 0); 94 cost += VP8LevelFixedCosts[flevel] + t[level]; 95 if (n < 15) { 96 const int b = VP8EncBands[n + 1]; 97 const int ctx = ctxs[n]; 98 const int last_p0 = res->prob[b][ctx][0]; 99 cost += VP8BitCost(0, last_p0); 100 } 101 } 102 return cost; 103 } 104 105 //------------------------------------------------------------------------------ 106 // Entry point 107 108 extern void VP8EncDspCostInitSSE2(void); 109 110 WEBP_TSAN_IGNORE_FUNCTION void VP8EncDspCostInitSSE2(void) { 111 VP8SetResidualCoeffs = SetResidualCoeffsSSE2; 112 VP8GetResidualCost = GetResidualCostSSE2; 113 } 114 115 #else // !WEBP_USE_SSE2 116 117 WEBP_DSP_INIT_STUB(VP8EncDspCostInitSSE2) 118 119 #endif // WEBP_USE_SSE2 120
