Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1228 insertions, 0 deletions

diff --git a/media/libwebp/src/dsp/dec_sse2.c b/media/libwebp/src/dsp/dec_sse2.c
new file mode 100644
index 0000000000..01e6bcb636
--- /dev/null
+++ b/media/libwebp/src/dsp/dec_sse2.c
@@ -0,0 +1,1228 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Use of this source code is governed by a BSD-style license
+// that can be found in the COPYING file in the root of the source
+// tree. An additional intellectual property rights grant can be found
+// in the file PATENTS. All contributing project authors may
+// be found in the AUTHORS file in the root of the source tree.
+// -----------------------------------------------------------------------------
+//
+// SSE2 version of some decoding functions (idct, loop filtering).
+//
+// Author: somnath@google.com (Somnath Banerjee)
+//         cduvivier@google.com (Christian Duvivier)
+
+#include "src/dsp/dsp.h"
+
+#if defined(WEBP_USE_SSE2)
+
+// The 3-coeff sparse transform in SSE2 is not really faster than the plain-C
+// one it seems => disable it by default. Uncomment the following to enable:
+#if !defined(USE_TRANSFORM_AC3)
+#define USE_TRANSFORM_AC3 0   // ALTERNATE_CODE
+#endif
+
+#include <emmintrin.h>
+#include "src/dsp/common_sse2.h"
+#include "src/dec/vp8i_dec.h"
+#include "src/utils/utils.h"
+
+//------------------------------------------------------------------------------
+// Transforms (Paragraph 14.4)
+
+static void Transform_SSE2(const int16_t* in, uint8_t* dst, int do_two) {
+  // This implementation makes use of 16-bit fixed point versions of two
+  // multiply constants:
+  //    K1 = sqrt(2) * cos (pi/8) ~= 85627 / 2^16
+  //    K2 = sqrt(2) * sin (pi/8) ~= 35468 / 2^16
+  //
+  // To be able to use signed 16-bit integers, we use the following trick to
+  // have constants within range:
+  // - Associated constants are obtained by subtracting the 16-bit fixed point
+  //   version of one:
+  //      k = K - (1 << 16)  =>  K = k + (1 << 16)
+  //      K1 = 85267  =>  k1 =  20091
+  //      K2 = 35468  =>  k2 = -30068
+  // - The multiplication of a variable by a constant become the sum of the
+  //   variable and the multiplication of that variable by the associated
+  //   constant:
+  //      (x * K) >> 16 = (x * (k + (1 << 16))) >> 16 = ((x * k ) >> 16) + x
+  const __m128i k1 = _mm_set1_epi16(20091);
+  const __m128i k2 = _mm_set1_epi16(-30068);
+  __m128i T0, T1, T2, T3;
+
+  // Load and concatenate the transform coefficients (we'll do two transforms
+  // in parallel). In the case of only one transform, the second half of the
+  // vectors will just contain random value we'll never use nor store.
+  __m128i in0, in1, in2, in3;
+  {
+    in0 = _mm_loadl_epi64((const __m128i*)&in[0]);
+    in1 = _mm_loadl_epi64((const __m128i*)&in[4]);
+    in2 = _mm_loadl_epi64((const __m128i*)&in[8]);
+    in3 = _mm_loadl_epi64((const __m128i*)&in[12]);
+    // a00 a10 a20 a30   x x x x
+    // a01 a11 a21 a31   x x x x
+    // a02 a12 a22 a32   x x x x
+    // a03 a13 a23 a33   x x x x
+    if (do_two) {
+      const __m128i inB0 = _mm_loadl_epi64((const __m128i*)&in[16]);
+      const __m128i inB1 = _mm_loadl_epi64((const __m128i*)&in[20]);
+      const __m128i inB2 = _mm_loadl_epi64((const __m128i*)&in[24]);
+      const __m128i inB3 = _mm_loadl_epi64((const __m128i*)&in[28]);
+      in0 = _mm_unpacklo_epi64(in0, inB0);
+      in1 = _mm_unpacklo_epi64(in1, inB1);
+      in2 = _mm_unpacklo_epi64(in2, inB2);
+      in3 = _mm_unpacklo_epi64(in3, inB3);
+      // a00 a10 a20 a30   b00 b10 b20 b30
+      // a01 a11 a21 a31   b01 b11 b21 b31
+      // a02 a12 a22 a32   b02 b12 b22 b32
+      // a03 a13 a23 a33   b03 b13 b23 b33
+    }
+  }
+
+  // Vertical pass and subsequent transpose.
+  {
+    // First pass, c and d calculations are longer because of the "trick"
+    // multiplications.
+    const __m128i a = _mm_add_epi16(in0, in2);
+    const __m128i b = _mm_sub_epi16(in0, in2);
+    // c = MUL(in1, K2) - MUL(in3, K1) = MUL(in1, k2) - MUL(in3, k1) + in1 - in3
+    const __m128i c1 = _mm_mulhi_epi16(in1, k2);
+    const __m128i c2 = _mm_mulhi_epi16(in3, k1);
+    const __m128i c3 = _mm_sub_epi16(in1, in3);
+    const __m128i c4 = _mm_sub_epi16(c1, c2);
+    const __m128i c = _mm_add_epi16(c3, c4);
+    // d = MUL(in1, K1) + MUL(in3, K2) = MUL(in1, k1) + MUL(in3, k2) + in1 + in3
+    const __m128i d1 = _mm_mulhi_epi16(in1, k1);
+    const __m128i d2 = _mm_mulhi_epi16(in3, k2);
+    const __m128i d3 = _mm_add_epi16(in1, in3);
+    const __m128i d4 = _mm_add_epi16(d1, d2);
+    const __m128i d = _mm_add_epi16(d3, d4);
+
+    // Second pass.
+    const __m128i tmp0 = _mm_add_epi16(a, d);
+    const __m128i tmp1 = _mm_add_epi16(b, c);
+    const __m128i tmp2 = _mm_sub_epi16(b, c);
+    const __m128i tmp3 = _mm_sub_epi16(a, d);
+
+    // Transpose the two 4x4.
+    VP8Transpose_2_4x4_16b(&tmp0, &tmp1, &tmp2, &tmp3, &T0, &T1, &T2, &T3);
+  }
+
+  // Horizontal pass and subsequent transpose.
+  {
+    // First pass, c and d calculations are longer because of the "trick"
+    // multiplications.
+    const __m128i four = _mm_set1_epi16(4);
+    const __m128i dc = _mm_add_epi16(T0, four);
+    const __m128i a =  _mm_add_epi16(dc, T2);
+    const __m128i b =  _mm_sub_epi16(dc, T2);
+    // c = MUL(T1, K2) - MUL(T3, K1) = MUL(T1, k2) - MUL(T3, k1) + T1 - T3
+    const __m128i c1 = _mm_mulhi_epi16(T1, k2);
+    const __m128i c2 = _mm_mulhi_epi16(T3, k1);
+    const __m128i c3 = _mm_sub_epi16(T1, T3);
+    const __m128i c4 = _mm_sub_epi16(c1, c2);
+    const __m128i c = _mm_add_epi16(c3, c4);
+    // d = MUL(T1, K1) + MUL(T3, K2) = MUL(T1, k1) + MUL(T3, k2) + T1 + T3
+    const __m128i d1 = _mm_mulhi_epi16(T1, k1);
+    const __m128i d2 = _mm_mulhi_epi16(T3, k2);
+    const __m128i d3 = _mm_add_epi16(T1, T3);
+    const __m128i d4 = _mm_add_epi16(d1, d2);
+    const __m128i d = _mm_add_epi16(d3, d4);
+
+    // Second pass.
+    const __m128i tmp0 = _mm_add_epi16(a, d);
+    const __m128i tmp1 = _mm_add_epi16(b, c);
+    const __m128i tmp2 = _mm_sub_epi16(b, c);
+    const __m128i tmp3 = _mm_sub_epi16(a, d);
+    const __m128i shifted0 = _mm_srai_epi16(tmp0, 3);
+    const __m128i shifted1 = _mm_srai_epi16(tmp1, 3);
+    const __m128i shifted2 = _mm_srai_epi16(tmp2, 3);
+    const __m128i shifted3 = _mm_srai_epi16(tmp3, 3);
+
+    // Transpose the two 4x4.
+    VP8Transpose_2_4x4_16b(&shifted0, &shifted1, &shifted2, &shifted3, &T0, &T1,
+                           &T2, &T3);
+  }
+
+  // Add inverse transform to 'dst' and store.
+  {
+    const __m128i zero = _mm_setzero_si128();
+    // Load the reference(s).
+    __m128i dst0, dst1, dst2, dst3;
+    if (do_two) {
+      // Load eight bytes/pixels per line.
+      dst0 = _mm_loadl_epi64((__m128i*)(dst + 0 * BPS));
+      dst1 = _mm_loadl_epi64((__m128i*)(dst + 1 * BPS));
+      dst2 = _mm_loadl_epi64((__m128i*)(dst + 2 * BPS));
+      dst3 = _mm_loadl_epi64((__m128i*)(dst + 3 * BPS));
+    } else {
+      // Load four bytes/pixels per line.
+      dst0 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 0 * BPS));
+      dst1 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 1 * BPS));
+      dst2 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 2 * BPS));
+      dst3 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 3 * BPS));
+    }
+    // Convert to 16b.
+    dst0 = _mm_unpacklo_epi8(dst0, zero);
+    dst1 = _mm_unpacklo_epi8(dst1, zero);
+    dst2 = _mm_unpacklo_epi8(dst2, zero);
+    dst3 = _mm_unpacklo_epi8(dst3, zero);
+    // Add the inverse transform(s).
+    dst0 = _mm_add_epi16(dst0, T0);
+    dst1 = _mm_add_epi16(dst1, T1);
+    dst2 = _mm_add_epi16(dst2, T2);
+    dst3 = _mm_add_epi16(dst3, T3);
+    // Unsigned saturate to 8b.
+    dst0 = _mm_packus_epi16(dst0, dst0);
+    dst1 = _mm_packus_epi16(dst1, dst1);
+    dst2 = _mm_packus_epi16(dst2, dst2);
+    dst3 = _mm_packus_epi16(dst3, dst3);
+    // Store the results.
+    if (do_two) {
+      // Store eight bytes/pixels per line.
+      _mm_storel_epi64((__m128i*)(dst + 0 * BPS), dst0);
+      _mm_storel_epi64((__m128i*)(dst + 1 * BPS), dst1);
+      _mm_storel_epi64((__m128i*)(dst + 2 * BPS), dst2);
+      _mm_storel_epi64((__m128i*)(dst + 3 * BPS), dst3);
+    } else {
+      // Store four bytes/pixels per line.
+      WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(dst0));
+      WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(dst1));
+      WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(dst2));
+      WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(dst3));
+    }
+  }
+}
+
+#if (USE_TRANSFORM_AC3 == 1)
+#define MUL(a, b) (((a) * (b)) >> 16)
+static void TransformAC3(const int16_t* in, uint8_t* dst) {
+  static const int kC1 = 20091 + (1 << 16);
+  static const int kC2 = 35468;
+  const __m128i A = _mm_set1_epi16(in[0] + 4);
+  const __m128i c4 = _mm_set1_epi16(MUL(in[4], kC2));
+  const __m128i d4 = _mm_set1_epi16(MUL(in[4], kC1));
+  const int c1 = MUL(in[1], kC2);
+  const int d1 = MUL(in[1], kC1);
+  const __m128i CD = _mm_set_epi16(0, 0, 0, 0, -d1, -c1, c1, d1);
+  const __m128i B = _mm_adds_epi16(A, CD);
+  const __m128i m0 = _mm_adds_epi16(B, d4);
+  const __m128i m1 = _mm_adds_epi16(B, c4);
+  const __m128i m2 = _mm_subs_epi16(B, c4);
+  const __m128i m3 = _mm_subs_epi16(B, d4);
+  const __m128i zero = _mm_setzero_si128();
+  // Load the source pixels.
+  __m128i dst0 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 0 * BPS));
+  __m128i dst1 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 1 * BPS));
+  __m128i dst2 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 2 * BPS));
+  __m128i dst3 = _mm_cvtsi32_si128(WebPMemToInt32(dst + 3 * BPS));
+  // Convert to 16b.
+  dst0 = _mm_unpacklo_epi8(dst0, zero);
+  dst1 = _mm_unpacklo_epi8(dst1, zero);
+  dst2 = _mm_unpacklo_epi8(dst2, zero);
+  dst3 = _mm_unpacklo_epi8(dst3, zero);
+  // Add the inverse transform.
+  dst0 = _mm_adds_epi16(dst0, _mm_srai_epi16(m0, 3));
+  dst1 = _mm_adds_epi16(dst1, _mm_srai_epi16(m1, 3));
+  dst2 = _mm_adds_epi16(dst2, _mm_srai_epi16(m2, 3));
+  dst3 = _mm_adds_epi16(dst3, _mm_srai_epi16(m3, 3));
+  // Unsigned saturate to 8b.
+  dst0 = _mm_packus_epi16(dst0, dst0);
+  dst1 = _mm_packus_epi16(dst1, dst1);
+  dst2 = _mm_packus_epi16(dst2, dst2);
+  dst3 = _mm_packus_epi16(dst3, dst3);
+  // Store the results.
+  WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(dst0));
+  WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(dst1));
+  WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(dst2));
+  WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(dst3));
+}
+#undef MUL
+#endif   // USE_TRANSFORM_AC3
+
+//------------------------------------------------------------------------------
+// Loop Filter (Paragraph 15)
+
+// Compute abs(p - q) = subs(p - q) OR subs(q - p)
+#define MM_ABS(p, q)  _mm_or_si128(                                            \
+    _mm_subs_epu8((q), (p)),                                                   \
+    _mm_subs_epu8((p), (q)))
+
+// Shift each byte of "x" by 3 bits while preserving by the sign bit.
+static WEBP_INLINE void SignedShift8b_SSE2(__m128i* const x) {
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i lo_0 = _mm_unpacklo_epi8(zero, *x);
+  const __m128i hi_0 = _mm_unpackhi_epi8(zero, *x);
+  const __m128i lo_1 = _mm_srai_epi16(lo_0, 3 + 8);
+  const __m128i hi_1 = _mm_srai_epi16(hi_0, 3 + 8);
+  *x = _mm_packs_epi16(lo_1, hi_1);
+}
+
+#define FLIP_SIGN_BIT2(a, b) {                                                 \
+  (a) = _mm_xor_si128(a, sign_bit);                                            \
+  (b) = _mm_xor_si128(b, sign_bit);                                            \
+}
+
+#define FLIP_SIGN_BIT4(a, b, c, d) {                                           \
+  FLIP_SIGN_BIT2(a, b);                                                        \
+  FLIP_SIGN_BIT2(c, d);                                                        \
+}
+
+// input/output is uint8_t
+static WEBP_INLINE void GetNotHEV_SSE2(const __m128i* const p1,
+                                       const __m128i* const p0,
+                                       const __m128i* const q0,
+                                       const __m128i* const q1,
+                                       int hev_thresh, __m128i* const not_hev) {
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i t_1 = MM_ABS(*p1, *p0);
+  const __m128i t_2 = MM_ABS(*q1, *q0);
+
+  const __m128i h = _mm_set1_epi8(hev_thresh);
+  const __m128i t_max = _mm_max_epu8(t_1, t_2);
+
+  const __m128i t_max_h = _mm_subs_epu8(t_max, h);
+  *not_hev = _mm_cmpeq_epi8(t_max_h, zero);  // not_hev <= t1 && not_hev <= t2
+}
+
+// input pixels are int8_t
+static WEBP_INLINE void GetBaseDelta_SSE2(const __m128i* const p1,
+                                          const __m128i* const p0,
+                                          const __m128i* const q0,
+                                          const __m128i* const q1,
+                                          __m128i* const delta) {
+  // beware of addition order, for saturation!
+  const __m128i p1_q1 = _mm_subs_epi8(*p1, *q1);   // p1 - q1
+  const __m128i q0_p0 = _mm_subs_epi8(*q0, *p0);   // q0 - p0
+  const __m128i s1 = _mm_adds_epi8(p1_q1, q0_p0);  // p1 - q1 + 1 * (q0 - p0)
+  const __m128i s2 = _mm_adds_epi8(q0_p0, s1);     // p1 - q1 + 2 * (q0 - p0)
+  const __m128i s3 = _mm_adds_epi8(q0_p0, s2);     // p1 - q1 + 3 * (q0 - p0)
+  *delta = s3;
+}
+
+// input and output are int8_t
+static WEBP_INLINE void DoSimpleFilter_SSE2(__m128i* const p0,
+                                            __m128i* const q0,
+                                            const __m128i* const fl) {
+  const __m128i k3 = _mm_set1_epi8(3);
+  const __m128i k4 = _mm_set1_epi8(4);
+  __m128i v3 = _mm_adds_epi8(*fl, k3);
+  __m128i v4 = _mm_adds_epi8(*fl, k4);
+
+  SignedShift8b_SSE2(&v4);             // v4 >> 3
+  SignedShift8b_SSE2(&v3);             // v3 >> 3
+  *q0 = _mm_subs_epi8(*q0, v4);        // q0 -= v4
+  *p0 = _mm_adds_epi8(*p0, v3);        // p0 += v3
+}
+
+// Updates values of 2 pixels at MB edge during complex filtering.
+// Update operations:
+// q = q - delta and p = p + delta; where delta = [(a_hi >> 7), (a_lo >> 7)]
+// Pixels 'pi' and 'qi' are int8_t on input, uint8_t on output (sign flip).
+static WEBP_INLINE void Update2Pixels_SSE2(__m128i* const pi, __m128i* const qi,
+                                           const __m128i* const a0_lo,
+                                           const __m128i* const a0_hi) {
+  const __m128i a1_lo = _mm_srai_epi16(*a0_lo, 7);
+  const __m128i a1_hi = _mm_srai_epi16(*a0_hi, 7);
+  const __m128i delta = _mm_packs_epi16(a1_lo, a1_hi);
+  const __m128i sign_bit = _mm_set1_epi8((char)0x80);
+  *pi = _mm_adds_epi8(*pi, delta);
+  *qi = _mm_subs_epi8(*qi, delta);
+  FLIP_SIGN_BIT2(*pi, *qi);
+}
+
+// input pixels are uint8_t
+static WEBP_INLINE void NeedsFilter_SSE2(const __m128i* const p1,
+                                         const __m128i* const p0,
+                                         const __m128i* const q0,
+                                         const __m128i* const q1,
+                                         int thresh, __m128i* const mask) {
+  const __m128i m_thresh = _mm_set1_epi8((char)thresh);
+  const __m128i t1 = MM_ABS(*p1, *q1);        // abs(p1 - q1)
+  const __m128i kFE = _mm_set1_epi8((char)0xFE);
+  const __m128i t2 = _mm_and_si128(t1, kFE);  // set lsb of each byte to zero
+  const __m128i t3 = _mm_srli_epi16(t2, 1);   // abs(p1 - q1) / 2
+
+  const __m128i t4 = MM_ABS(*p0, *q0);        // abs(p0 - q0)
+  const __m128i t5 = _mm_adds_epu8(t4, t4);   // abs(p0 - q0) * 2
+  const __m128i t6 = _mm_adds_epu8(t5, t3);   // abs(p0-q0)*2 + abs(p1-q1)/2
+
+  const __m128i t7 = _mm_subs_epu8(t6, m_thresh);  // mask <= m_thresh
+  *mask = _mm_cmpeq_epi8(t7, _mm_setzero_si128());
+}
+
+//------------------------------------------------------------------------------
+// Edge filtering functions
+
+// Applies filter on 2 pixels (p0 and q0)
+static WEBP_INLINE void DoFilter2_SSE2(__m128i* const p1, __m128i* const p0,
+                                       __m128i* const q0, __m128i* const q1,
+                                       int thresh) {
+  __m128i a, mask;
+  const __m128i sign_bit = _mm_set1_epi8((char)0x80);
+  // convert p1/q1 to int8_t (for GetBaseDelta_SSE2)
+  const __m128i p1s = _mm_xor_si128(*p1, sign_bit);
+  const __m128i q1s = _mm_xor_si128(*q1, sign_bit);
+
+  NeedsFilter_SSE2(p1, p0, q0, q1, thresh, &mask);
+
+  FLIP_SIGN_BIT2(*p0, *q0);
+  GetBaseDelta_SSE2(&p1s, p0, q0, &q1s, &a);
+  a = _mm_and_si128(a, mask);     // mask filter values we don't care about
+  DoSimpleFilter_SSE2(p0, q0, &a);
+  FLIP_SIGN_BIT2(*p0, *q0);
+}
+
+// Applies filter on 4 pixels (p1, p0, q0 and q1)
+static WEBP_INLINE void DoFilter4_SSE2(__m128i* const p1, __m128i* const p0,
+                                       __m128i* const q0, __m128i* const q1,
+                                       const __m128i* const mask,
+                                       int hev_thresh) {
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i sign_bit = _mm_set1_epi8((char)0x80);
+  const __m128i k64 = _mm_set1_epi8(64);
+  const __m128i k3 = _mm_set1_epi8(3);
+  const __m128i k4 = _mm_set1_epi8(4);
+  __m128i not_hev;
+  __m128i t1, t2, t3;
+
+  // compute hev mask
+  GetNotHEV_SSE2(p1, p0, q0, q1, hev_thresh, &not_hev);
+
+  // convert to signed values
+  FLIP_SIGN_BIT4(*p1, *p0, *q0, *q1);
+
+  t1 = _mm_subs_epi8(*p1, *q1);        // p1 - q1
+  t1 = _mm_andnot_si128(not_hev, t1);  // hev(p1 - q1)
+  t2 = _mm_subs_epi8(*q0, *p0);        // q0 - p0
+  t1 = _mm_adds_epi8(t1, t2);          // hev(p1 - q1) + 1 * (q0 - p0)
+  t1 = _mm_adds_epi8(t1, t2);          // hev(p1 - q1) + 2 * (q0 - p0)
+  t1 = _mm_adds_epi8(t1, t2);          // hev(p1 - q1) + 3 * (q0 - p0)
+  t1 = _mm_and_si128(t1, *mask);       // mask filter values we don't care about
+
+  t2 = _mm_adds_epi8(t1, k3);        // 3 * (q0 - p0) + hev(p1 - q1) + 3
+  t3 = _mm_adds_epi8(t1, k4);        // 3 * (q0 - p0) + hev(p1 - q1) + 4
+  SignedShift8b_SSE2(&t2);           // (3 * (q0 - p0) + hev(p1 - q1) + 3) >> 3
+  SignedShift8b_SSE2(&t3);           // (3 * (q0 - p0) + hev(p1 - q1) + 4) >> 3
+  *p0 = _mm_adds_epi8(*p0, t2);      // p0 += t2
+  *q0 = _mm_subs_epi8(*q0, t3);      // q0 -= t3
+  FLIP_SIGN_BIT2(*p0, *q0);
+
+  // this is equivalent to signed (a + 1) >> 1 calculation
+  t2 = _mm_add_epi8(t3, sign_bit);
+  t3 = _mm_avg_epu8(t2, zero);
+  t3 = _mm_sub_epi8(t3, k64);
+
+  t3 = _mm_and_si128(not_hev, t3);   // if !hev
+  *q1 = _mm_subs_epi8(*q1, t3);      // q1 -= t3
+  *p1 = _mm_adds_epi8(*p1, t3);      // p1 += t3
+  FLIP_SIGN_BIT2(*p1, *q1);
+}
+
+// Applies filter on 6 pixels (p2, p1, p0, q0, q1 and q2)
+static WEBP_INLINE void DoFilter6_SSE2(__m128i* const p2, __m128i* const p1,
+                                       __m128i* const p0, __m128i* const q0,
+                                       __m128i* const q1, __m128i* const q2,
+                                       const __m128i* const mask,
+                                       int hev_thresh) {
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i sign_bit = _mm_set1_epi8((char)0x80);
+  __m128i a, not_hev;
+
+  // compute hev mask
+  GetNotHEV_SSE2(p1, p0, q0, q1, hev_thresh, &not_hev);
+
+  FLIP_SIGN_BIT4(*p1, *p0, *q0, *q1);
+  FLIP_SIGN_BIT2(*p2, *q2);
+  GetBaseDelta_SSE2(p1, p0, q0, q1, &a);
+
+  { // do simple filter on pixels with hev
+    const __m128i m = _mm_andnot_si128(not_hev, *mask);
+    const __m128i f = _mm_and_si128(a, m);
+    DoSimpleFilter_SSE2(p0, q0, &f);
+  }
+
+  { // do strong filter on pixels with not hev
+    const __m128i k9 = _mm_set1_epi16(0x0900);
+    const __m128i k63 = _mm_set1_epi16(63);
+
+    const __m128i m = _mm_and_si128(not_hev, *mask);
+    const __m128i f = _mm_and_si128(a, m);
+
+    const __m128i f_lo = _mm_unpacklo_epi8(zero, f);
+    const __m128i f_hi = _mm_unpackhi_epi8(zero, f);
+
+    const __m128i f9_lo = _mm_mulhi_epi16(f_lo, k9);    // Filter (lo) * 9
+    const __m128i f9_hi = _mm_mulhi_epi16(f_hi, k9);    // Filter (hi) * 9
+
+    const __m128i a2_lo = _mm_add_epi16(f9_lo, k63);    // Filter * 9 + 63
+    const __m128i a2_hi = _mm_add_epi16(f9_hi, k63);    // Filter * 9 + 63
+
+    const __m128i a1_lo = _mm_add_epi16(a2_lo, f9_lo);  // Filter * 18 + 63
+    const __m128i a1_hi = _mm_add_epi16(a2_hi, f9_hi);  // Filter * 18 + 63
+
+    const __m128i a0_lo = _mm_add_epi16(a1_lo, f9_lo);  // Filter * 27 + 63
+    const __m128i a0_hi = _mm_add_epi16(a1_hi, f9_hi);  // Filter * 27 + 63
+
+    Update2Pixels_SSE2(p2, q2, &a2_lo, &a2_hi);
+    Update2Pixels_SSE2(p1, q1, &a1_lo, &a1_hi);
+    Update2Pixels_SSE2(p0, q0, &a0_lo, &a0_hi);
+  }
+}
+
+// reads 8 rows across a vertical edge.
+static WEBP_INLINE void Load8x4_SSE2(const uint8_t* const b, int stride,
+                                     __m128i* const p, __m128i* const q) {
+  // A0 = 63 62 61 60 23 22 21 20 43 42 41 40 03 02 01 00
+  // A1 = 73 72 71 70 33 32 31 30 53 52 51 50 13 12 11 10
+  const __m128i A0 = _mm_set_epi32(
+      WebPMemToInt32(&b[6 * stride]), WebPMemToInt32(&b[2 * stride]),
+      WebPMemToInt32(&b[4 * stride]), WebPMemToInt32(&b[0 * stride]));
+  const __m128i A1 = _mm_set_epi32(
+      WebPMemToInt32(&b[7 * stride]), WebPMemToInt32(&b[3 * stride]),
+      WebPMemToInt32(&b[5 * stride]), WebPMemToInt32(&b[1 * stride]));
+
+  // B0 = 53 43 52 42 51 41 50 40 13 03 12 02 11 01 10 00
+  // B1 = 73 63 72 62 71 61 70 60 33 23 32 22 31 21 30 20
+  const __m128i B0 = _mm_unpacklo_epi8(A0, A1);
+  const __m128i B1 = _mm_unpackhi_epi8(A0, A1);
+
+  // C0 = 33 23 13 03 32 22 12 02 31 21 11 01 30 20 10 00
+  // C1 = 73 63 53 43 72 62 52 42 71 61 51 41 70 60 50 40
+  const __m128i C0 = _mm_unpacklo_epi16(B0, B1);
+  const __m128i C1 = _mm_unpackhi_epi16(B0, B1);
+
+  // *p = 71 61 51 41 31 21 11 01 70 60 50 40 30 20 10 00
+  // *q = 73 63 53 43 33 23 13 03 72 62 52 42 32 22 12 02
+  *p = _mm_unpacklo_epi32(C0, C1);
+  *q = _mm_unpackhi_epi32(C0, C1);
+}
+
+static WEBP_INLINE void Load16x4_SSE2(const uint8_t* const r0,
+                                      const uint8_t* const r8,
+                                      int stride,
+                                      __m128i* const p1, __m128i* const p0,
+                                      __m128i* const q0, __m128i* const q1) {
+  // Assume the pixels around the edge (|) are numbered as follows
+  //                00 01 | 02 03
+  //                10 11 | 12 13
+  //                 ...  |  ...
+  //                e0 e1 | e2 e3
+  //                f0 f1 | f2 f3
+  //
+  // r0 is pointing to the 0th row (00)
+  // r8 is pointing to the 8th row (80)
+
+  // Load
+  // p1 = 71 61 51 41 31 21 11 01 70 60 50 40 30 20 10 00
+  // q0 = 73 63 53 43 33 23 13 03 72 62 52 42 32 22 12 02
+  // p0 = f1 e1 d1 c1 b1 a1 91 81 f0 e0 d0 c0 b0 a0 90 80
+  // q1 = f3 e3 d3 c3 b3 a3 93 83 f2 e2 d2 c2 b2 a2 92 82
+  Load8x4_SSE2(r0, stride, p1, q0);
+  Load8x4_SSE2(r8, stride, p0, q1);
+
+  {
+    // p1 = f0 e0 d0 c0 b0 a0 90 80 70 60 50 40 30 20 10 00
+    // p0 = f1 e1 d1 c1 b1 a1 91 81 71 61 51 41 31 21 11 01
+    // q0 = f2 e2 d2 c2 b2 a2 92 82 72 62 52 42 32 22 12 02
+    // q1 = f3 e3 d3 c3 b3 a3 93 83 73 63 53 43 33 23 13 03
+    const __m128i t1 = *p1;
+    const __m128i t2 = *q0;
+    *p1 = _mm_unpacklo_epi64(t1, *p0);
+    *p0 = _mm_unpackhi_epi64(t1, *p0);
+    *q0 = _mm_unpacklo_epi64(t2, *q1);
+    *q1 = _mm_unpackhi_epi64(t2, *q1);
+  }
+}
+
+static WEBP_INLINE void Store4x4_SSE2(__m128i* const x,
+                                      uint8_t* dst, int stride) {
+  int i;
+  for (i = 0; i < 4; ++i, dst += stride) {
+    WebPInt32ToMem(dst, _mm_cvtsi128_si32(*x));
+    *x = _mm_srli_si128(*x, 4);
+  }
+}
+
+// Transpose back and store
+static WEBP_INLINE void Store16x4_SSE2(const __m128i* const p1,
+                                       const __m128i* const p0,
+                                       const __m128i* const q0,
+                                       const __m128i* const q1,
+                                       uint8_t* r0, uint8_t* r8,
+                                       int stride) {
+  __m128i t1, p1_s, p0_s, q0_s, q1_s;
+
+  // p0 = 71 70 61 60 51 50 41 40 31 30 21 20 11 10 01 00
+  // p1 = f1 f0 e1 e0 d1 d0 c1 c0 b1 b0 a1 a0 91 90 81 80
+  t1 = *p0;
+  p0_s = _mm_unpacklo_epi8(*p1, t1);
+  p1_s = _mm_unpackhi_epi8(*p1, t1);
+
+  // q0 = 73 72 63 62 53 52 43 42 33 32 23 22 13 12 03 02
+  // q1 = f3 f2 e3 e2 d3 d2 c3 c2 b3 b2 a3 a2 93 92 83 82
+  t1 = *q0;
+  q0_s = _mm_unpacklo_epi8(t1, *q1);
+  q1_s = _mm_unpackhi_epi8(t1, *q1);
+
+  // p0 = 33 32 31 30 23 22 21 20 13 12 11 10 03 02 01 00
+  // q0 = 73 72 71 70 63 62 61 60 53 52 51 50 43 42 41 40
+  t1 = p0_s;
+  p0_s = _mm_unpacklo_epi16(t1, q0_s);
+  q0_s = _mm_unpackhi_epi16(t1, q0_s);
+
+  // p1 = b3 b2 b1 b0 a3 a2 a1 a0 93 92 91 90 83 82 81 80
+  // q1 = f3 f2 f1 f0 e3 e2 e1 e0 d3 d2 d1 d0 c3 c2 c1 c0
+  t1 = p1_s;
+  p1_s = _mm_unpacklo_epi16(t1, q1_s);
+  q1_s = _mm_unpackhi_epi16(t1, q1_s);
+
+  Store4x4_SSE2(&p0_s, r0, stride);
+  r0 += 4 * stride;
+  Store4x4_SSE2(&q0_s, r0, stride);
+
+  Store4x4_SSE2(&p1_s, r8, stride);
+  r8 += 4 * stride;
+  Store4x4_SSE2(&q1_s, r8, stride);
+}
+
+//------------------------------------------------------------------------------
+// Simple In-loop filtering (Paragraph 15.2)
+
+static void SimpleVFilter16_SSE2(uint8_t* p, int stride, int thresh) {
+  // Load
+  __m128i p1 = _mm_loadu_si128((__m128i*)&p[-2 * stride]);
+  __m128i p0 = _mm_loadu_si128((__m128i*)&p[-stride]);
+  __m128i q0 = _mm_loadu_si128((__m128i*)&p[0]);
+  __m128i q1 = _mm_loadu_si128((__m128i*)&p[stride]);
+
+  DoFilter2_SSE2(&p1, &p0, &q0, &q1, thresh);
+
+  // Store
+  _mm_storeu_si128((__m128i*)&p[-stride], p0);
+  _mm_storeu_si128((__m128i*)&p[0], q0);
+}
+
+static void SimpleHFilter16_SSE2(uint8_t* p, int stride, int thresh) {
+  __m128i p1, p0, q0, q1;
+
+  p -= 2;  // beginning of p1
+
+  Load16x4_SSE2(p, p + 8 * stride, stride, &p1, &p0, &q0, &q1);
+  DoFilter2_SSE2(&p1, &p0, &q0, &q1, thresh);
+  Store16x4_SSE2(&p1, &p0, &q0, &q1, p, p + 8 * stride, stride);
+}
+
+static void SimpleVFilter16i_SSE2(uint8_t* p, int stride, int thresh) {
+  int k;
+  for (k = 3; k > 0; --k) {
+    p += 4 * stride;
+    SimpleVFilter16_SSE2(p, stride, thresh);
+  }
+}
+
+static void SimpleHFilter16i_SSE2(uint8_t* p, int stride, int thresh) {
+  int k;
+  for (k = 3; k > 0; --k) {
+    p += 4;
+    SimpleHFilter16_SSE2(p, stride, thresh);
+  }
+}
+
+//------------------------------------------------------------------------------
+// Complex In-loop filtering (Paragraph 15.3)
+
+#define MAX_DIFF1(p3, p2, p1, p0, m) do {                                      \
+  (m) = MM_ABS(p1, p0);                                                        \
+  (m) = _mm_max_epu8(m, MM_ABS(p3, p2));                                       \
+  (m) = _mm_max_epu8(m, MM_ABS(p2, p1));                                       \
+} while (0)
+
+#define MAX_DIFF2(p3, p2, p1, p0, m) do {                                      \
+  (m) = _mm_max_epu8(m, MM_ABS(p1, p0));                                       \
+  (m) = _mm_max_epu8(m, MM_ABS(p3, p2));                                       \
+  (m) = _mm_max_epu8(m, MM_ABS(p2, p1));                                       \
+} while (0)
+
+#define LOAD_H_EDGES4(p, stride, e1, e2, e3, e4) {                             \
+  (e1) = _mm_loadu_si128((__m128i*)&(p)[0 * (stride)]);                        \
+  (e2) = _mm_loadu_si128((__m128i*)&(p)[1 * (stride)]);                        \
+  (e3) = _mm_loadu_si128((__m128i*)&(p)[2 * (stride)]);                        \
+  (e4) = _mm_loadu_si128((__m128i*)&(p)[3 * (stride)]);                        \
+}
+
+#define LOADUV_H_EDGE(p, u, v, stride) do {                                    \
+  const __m128i U = _mm_loadl_epi64((__m128i*)&(u)[(stride)]);                 \
+  const __m128i V = _mm_loadl_epi64((__m128i*)&(v)[(stride)]);                 \
+  (p) = _mm_unpacklo_epi64(U, V);                                              \
+} while (0)
+
+#define LOADUV_H_EDGES4(u, v, stride, e1, e2, e3, e4) {                        \
+  LOADUV_H_EDGE(e1, u, v, 0 * (stride));                                       \
+  LOADUV_H_EDGE(e2, u, v, 1 * (stride));                                       \
+  LOADUV_H_EDGE(e3, u, v, 2 * (stride));                                       \
+  LOADUV_H_EDGE(e4, u, v, 3 * (stride));                                       \
+}
+
+#define STOREUV(p, u, v, stride) {                                             \
+  _mm_storel_epi64((__m128i*)&(u)[(stride)], p);                               \
+  (p) = _mm_srli_si128(p, 8);                                                  \
+  _mm_storel_epi64((__m128i*)&(v)[(stride)], p);                               \
+}
+
+static WEBP_INLINE void ComplexMask_SSE2(const __m128i* const p1,
+                                         const __m128i* const p0,
+                                         const __m128i* const q0,
+                                         const __m128i* const q1,
+                                         int thresh, int ithresh,
+                                         __m128i* const mask) {
+  const __m128i it = _mm_set1_epi8(ithresh);
+  const __m128i diff = _mm_subs_epu8(*mask, it);
+  const __m128i thresh_mask = _mm_cmpeq_epi8(diff, _mm_setzero_si128());
+  __m128i filter_mask;
+  NeedsFilter_SSE2(p1, p0, q0, q1, thresh, &filter_mask);
+  *mask = _mm_and_si128(thresh_mask, filter_mask);
+}
+
+// on macroblock edges
+static void VFilter16_SSE2(uint8_t* p, int stride,
+                           int thresh, int ithresh, int hev_thresh) {
+  __m128i t1;
+  __m128i mask;
+  __m128i p2, p1, p0, q0, q1, q2;
+
+  // Load p3, p2, p1, p0
+  LOAD_H_EDGES4(p - 4 * stride, stride, t1, p2, p1, p0);
+  MAX_DIFF1(t1, p2, p1, p0, mask);
+
+  // Load q0, q1, q2, q3
+  LOAD_H_EDGES4(p, stride, q0, q1, q2, t1);
+  MAX_DIFF2(t1, q2, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter6_SSE2(&p2, &p1, &p0, &q0, &q1, &q2, &mask, hev_thresh);
+
+  // Store
+  _mm_storeu_si128((__m128i*)&p[-3 * stride], p2);
+  _mm_storeu_si128((__m128i*)&p[-2 * stride], p1);
+  _mm_storeu_si128((__m128i*)&p[-1 * stride], p0);
+  _mm_storeu_si128((__m128i*)&p[+0 * stride], q0);
+  _mm_storeu_si128((__m128i*)&p[+1 * stride], q1);
+  _mm_storeu_si128((__m128i*)&p[+2 * stride], q2);
+}
+
+static void HFilter16_SSE2(uint8_t* p, int stride,
+                           int thresh, int ithresh, int hev_thresh) {
+  __m128i mask;
+  __m128i p3, p2, p1, p0, q0, q1, q2, q3;
+
+  uint8_t* const b = p - 4;
+  Load16x4_SSE2(b, b + 8 * stride, stride, &p3, &p2, &p1, &p0);
+  MAX_DIFF1(p3, p2, p1, p0, mask);
+
+  Load16x4_SSE2(p, p + 8 * stride, stride, &q0, &q1, &q2, &q3);
+  MAX_DIFF2(q3, q2, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter6_SSE2(&p2, &p1, &p0, &q0, &q1, &q2, &mask, hev_thresh);
+
+  Store16x4_SSE2(&p3, &p2, &p1, &p0, b, b + 8 * stride, stride);
+  Store16x4_SSE2(&q0, &q1, &q2, &q3, p, p + 8 * stride, stride);
+}
+
+// on three inner edges
+static void VFilter16i_SSE2(uint8_t* p, int stride,
+                            int thresh, int ithresh, int hev_thresh) {
+  int k;
+  __m128i p3, p2, p1, p0;   // loop invariants
+
+  LOAD_H_EDGES4(p, stride, p3, p2, p1, p0);  // prologue
+
+  for (k = 3; k > 0; --k) {
+    __m128i mask, tmp1, tmp2;
+    uint8_t* const b = p + 2 * stride;   // beginning of p1
+    p += 4 * stride;
+
+    MAX_DIFF1(p3, p2, p1, p0, mask);   // compute partial mask
+    LOAD_H_EDGES4(p, stride, p3, p2, tmp1, tmp2);
+    MAX_DIFF2(p3, p2, tmp1, tmp2, mask);
+
+    // p3 and p2 are not just temporary variables here: they will be
+    // re-used for next span. And q2/q3 will become p1/p0 accordingly.
+    ComplexMask_SSE2(&p1, &p0, &p3, &p2, thresh, ithresh, &mask);
+    DoFilter4_SSE2(&p1, &p0, &p3, &p2, &mask, hev_thresh);
+
+    // Store
+    _mm_storeu_si128((__m128i*)&b[0 * stride], p1);
+    _mm_storeu_si128((__m128i*)&b[1 * stride], p0);
+    _mm_storeu_si128((__m128i*)&b[2 * stride], p3);
+    _mm_storeu_si128((__m128i*)&b[3 * stride], p2);
+
+    // rotate samples
+    p1 = tmp1;
+    p0 = tmp2;
+  }
+}
+
+static void HFilter16i_SSE2(uint8_t* p, int stride,
+                            int thresh, int ithresh, int hev_thresh) {
+  int k;
+  __m128i p3, p2, p1, p0;   // loop invariants
+
+  Load16x4_SSE2(p, p + 8 * stride, stride, &p3, &p2, &p1, &p0);  // prologue
+
+  for (k = 3; k > 0; --k) {
+    __m128i mask, tmp1, tmp2;
+    uint8_t* const b = p + 2;   // beginning of p1
+
+    p += 4;  // beginning of q0 (and next span)
+
+    MAX_DIFF1(p3, p2, p1, p0, mask);   // compute partial mask
+    Load16x4_SSE2(p, p + 8 * stride, stride, &p3, &p2, &tmp1, &tmp2);
+    MAX_DIFF2(p3, p2, tmp1, tmp2, mask);
+
+    ComplexMask_SSE2(&p1, &p0, &p3, &p2, thresh, ithresh, &mask);
+    DoFilter4_SSE2(&p1, &p0, &p3, &p2, &mask, hev_thresh);
+
+    Store16x4_SSE2(&p1, &p0, &p3, &p2, b, b + 8 * stride, stride);
+
+    // rotate samples
+    p1 = tmp1;
+    p0 = tmp2;
+  }
+}
+
+// 8-pixels wide variant, for chroma filtering
+static void VFilter8_SSE2(uint8_t* u, uint8_t* v, int stride,
+                          int thresh, int ithresh, int hev_thresh) {
+  __m128i mask;
+  __m128i t1, p2, p1, p0, q0, q1, q2;
+
+  // Load p3, p2, p1, p0
+  LOADUV_H_EDGES4(u - 4 * stride, v - 4 * stride, stride, t1, p2, p1, p0);
+  MAX_DIFF1(t1, p2, p1, p0, mask);
+
+  // Load q0, q1, q2, q3
+  LOADUV_H_EDGES4(u, v, stride, q0, q1, q2, t1);
+  MAX_DIFF2(t1, q2, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter6_SSE2(&p2, &p1, &p0, &q0, &q1, &q2, &mask, hev_thresh);
+
+  // Store
+  STOREUV(p2, u, v, -3 * stride);
+  STOREUV(p1, u, v, -2 * stride);
+  STOREUV(p0, u, v, -1 * stride);
+  STOREUV(q0, u, v, 0 * stride);
+  STOREUV(q1, u, v, 1 * stride);
+  STOREUV(q2, u, v, 2 * stride);
+}
+
+static void HFilter8_SSE2(uint8_t* u, uint8_t* v, int stride,
+                          int thresh, int ithresh, int hev_thresh) {
+  __m128i mask;
+  __m128i p3, p2, p1, p0, q0, q1, q2, q3;
+
+  uint8_t* const tu = u - 4;
+  uint8_t* const tv = v - 4;
+  Load16x4_SSE2(tu, tv, stride, &p3, &p2, &p1, &p0);
+  MAX_DIFF1(p3, p2, p1, p0, mask);
+
+  Load16x4_SSE2(u, v, stride, &q0, &q1, &q2, &q3);
+  MAX_DIFF2(q3, q2, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter6_SSE2(&p2, &p1, &p0, &q0, &q1, &q2, &mask, hev_thresh);
+
+  Store16x4_SSE2(&p3, &p2, &p1, &p0, tu, tv, stride);
+  Store16x4_SSE2(&q0, &q1, &q2, &q3, u, v, stride);
+}
+
+static void VFilter8i_SSE2(uint8_t* u, uint8_t* v, int stride,
+                           int thresh, int ithresh, int hev_thresh) {
+  __m128i mask;
+  __m128i t1, t2, p1, p0, q0, q1;
+
+  // Load p3, p2, p1, p0
+  LOADUV_H_EDGES4(u, v, stride, t2, t1, p1, p0);
+  MAX_DIFF1(t2, t1, p1, p0, mask);
+
+  u += 4 * stride;
+  v += 4 * stride;
+
+  // Load q0, q1, q2, q3
+  LOADUV_H_EDGES4(u, v, stride, q0, q1, t1, t2);
+  MAX_DIFF2(t2, t1, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter4_SSE2(&p1, &p0, &q0, &q1, &mask, hev_thresh);
+
+  // Store
+  STOREUV(p1, u, v, -2 * stride);
+  STOREUV(p0, u, v, -1 * stride);
+  STOREUV(q0, u, v, 0 * stride);
+  STOREUV(q1, u, v, 1 * stride);
+}
+
+static void HFilter8i_SSE2(uint8_t* u, uint8_t* v, int stride,
+                           int thresh, int ithresh, int hev_thresh) {
+  __m128i mask;
+  __m128i t1, t2, p1, p0, q0, q1;
+  Load16x4_SSE2(u, v, stride, &t2, &t1, &p1, &p0);   // p3, p2, p1, p0
+  MAX_DIFF1(t2, t1, p1, p0, mask);
+
+  u += 4;  // beginning of q0
+  v += 4;
+  Load16x4_SSE2(u, v, stride, &q0, &q1, &t1, &t2);  // q0, q1, q2, q3
+  MAX_DIFF2(t2, t1, q1, q0, mask);
+
+  ComplexMask_SSE2(&p1, &p0, &q0, &q1, thresh, ithresh, &mask);
+  DoFilter4_SSE2(&p1, &p0, &q0, &q1, &mask, hev_thresh);
+
+  u -= 2;  // beginning of p1
+  v -= 2;
+  Store16x4_SSE2(&p1, &p0, &q0, &q1, u, v, stride);
+}
+
+//------------------------------------------------------------------------------
+// 4x4 predictions
+
+#define DST(x, y) dst[(x) + (y) * BPS]
+#define AVG3(a, b, c) (((a) + 2 * (b) + (c) + 2) >> 2)
+
+// We use the following 8b-arithmetic tricks:
+//     (a + 2 * b + c + 2) >> 2 = (AC + b + 1) >> 1
+//   where: AC = (a + c) >> 1 = [(a + c + 1) >> 1] - [(a^c) & 1]
+// and:
+//     (a + 2 * b + c + 2) >> 2 = (AB + BC + 1) >> 1 - (ab|bc)&lsb
+//   where: AC = (a + b + 1) >> 1,   BC = (b + c + 1) >> 1
+//   and ab = a ^ b, bc = b ^ c, lsb = (AC^BC)&1
+
+static void VE4_SSE2(uint8_t* dst) {    // vertical
+  const __m128i one = _mm_set1_epi8(1);
+  const __m128i ABCDEFGH = _mm_loadl_epi64((__m128i*)(dst - BPS - 1));
+  const __m128i BCDEFGH0 = _mm_srli_si128(ABCDEFGH, 1);
+  const __m128i CDEFGH00 = _mm_srli_si128(ABCDEFGH, 2);
+  const __m128i a = _mm_avg_epu8(ABCDEFGH, CDEFGH00);
+  const __m128i lsb = _mm_and_si128(_mm_xor_si128(ABCDEFGH, CDEFGH00), one);
+  const __m128i b = _mm_subs_epu8(a, lsb);
+  const __m128i avg = _mm_avg_epu8(b, BCDEFGH0);
+  const int vals = _mm_cvtsi128_si32(avg);
+  int i;
+  for (i = 0; i < 4; ++i) {
+    WebPInt32ToMem(dst + i * BPS, vals);
+  }
+}
+
+static void LD4_SSE2(uint8_t* dst) {   // Down-Left
+  const __m128i one = _mm_set1_epi8(1);
+  const __m128i ABCDEFGH = _mm_loadl_epi64((__m128i*)(dst - BPS));
+  const __m128i BCDEFGH0 = _mm_srli_si128(ABCDEFGH, 1);
+  const __m128i CDEFGH00 = _mm_srli_si128(ABCDEFGH, 2);
+  const __m128i CDEFGHH0 = _mm_insert_epi16(CDEFGH00, dst[-BPS + 7], 3);
+  const __m128i avg1 = _mm_avg_epu8(ABCDEFGH, CDEFGHH0);
+  const __m128i lsb = _mm_and_si128(_mm_xor_si128(ABCDEFGH, CDEFGHH0), one);
+  const __m128i avg2 = _mm_subs_epu8(avg1, lsb);
+  const __m128i abcdefg = _mm_avg_epu8(avg2, BCDEFGH0);
+  WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(               abcdefg    ));
+  WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 1)));
+  WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 2)));
+  WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 3)));
+}
+
+static void VR4_SSE2(uint8_t* dst) {   // Vertical-Right
+  const __m128i one = _mm_set1_epi8(1);
+  const int I = dst[-1 + 0 * BPS];
+  const int J = dst[-1 + 1 * BPS];
+  const int K = dst[-1 + 2 * BPS];
+  const int X = dst[-1 - BPS];
+  const __m128i XABCD = _mm_loadl_epi64((__m128i*)(dst - BPS - 1));
+  const __m128i ABCD0 = _mm_srli_si128(XABCD, 1);
+  const __m128i abcd = _mm_avg_epu8(XABCD, ABCD0);
+  const __m128i _XABCD = _mm_slli_si128(XABCD, 1);
+  const __m128i IXABCD = _mm_insert_epi16(_XABCD, (short)(I | (X << 8)), 0);
+  const __m128i avg1 = _mm_avg_epu8(IXABCD, ABCD0);
+  const __m128i lsb = _mm_and_si128(_mm_xor_si128(IXABCD, ABCD0), one);
+  const __m128i avg2 = _mm_subs_epu8(avg1, lsb);
+  const __m128i efgh = _mm_avg_epu8(avg2, XABCD);
+  WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(               abcd    ));
+  WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(               efgh    ));
+  WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(_mm_slli_si128(abcd, 1)));
+  WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(_mm_slli_si128(efgh, 1)));
+
+  // these two are hard to implement in SSE2, so we keep the C-version:
+  DST(0, 2) = AVG3(J, I, X);
+  DST(0, 3) = AVG3(K, J, I);
+}
+
+static void VL4_SSE2(uint8_t* dst) {   // Vertical-Left
+  const __m128i one = _mm_set1_epi8(1);
+  const __m128i ABCDEFGH = _mm_loadl_epi64((__m128i*)(dst - BPS));
+  const __m128i BCDEFGH_ = _mm_srli_si128(ABCDEFGH, 1);
+  const __m128i CDEFGH__ = _mm_srli_si128(ABCDEFGH, 2);
+  const __m128i avg1 = _mm_avg_epu8(ABCDEFGH, BCDEFGH_);
+  const __m128i avg2 = _mm_avg_epu8(CDEFGH__, BCDEFGH_);
+  const __m128i avg3 = _mm_avg_epu8(avg1, avg2);
+  const __m128i lsb1 = _mm_and_si128(_mm_xor_si128(avg1, avg2), one);
+  const __m128i ab = _mm_xor_si128(ABCDEFGH, BCDEFGH_);
+  const __m128i bc = _mm_xor_si128(CDEFGH__, BCDEFGH_);
+  const __m128i abbc = _mm_or_si128(ab, bc);
+  const __m128i lsb2 = _mm_and_si128(abbc, lsb1);
+  const __m128i avg4 = _mm_subs_epu8(avg3, lsb2);
+  const uint32_t extra_out =
+      (uint32_t)_mm_cvtsi128_si32(_mm_srli_si128(avg4, 4));
+  WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(               avg1    ));
+  WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(               avg4    ));
+  WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(avg1, 1)));
+  WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(avg4, 1)));
+
+  // these two are hard to get and irregular
+  DST(3, 2) = (extra_out >> 0) & 0xff;
+  DST(3, 3) = (extra_out >> 8) & 0xff;
+}
+
+static void RD4_SSE2(uint8_t* dst) {   // Down-right
+  const __m128i one = _mm_set1_epi8(1);
+  const __m128i XABCD = _mm_loadl_epi64((__m128i*)(dst - BPS - 1));
+  const __m128i ____XABCD = _mm_slli_si128(XABCD, 4);
+  const uint32_t I = dst[-1 + 0 * BPS];
+  const uint32_t J = dst[-1 + 1 * BPS];
+  const uint32_t K = dst[-1 + 2 * BPS];
+  const uint32_t L = dst[-1 + 3 * BPS];
+  const __m128i LKJI_____ =
+      _mm_cvtsi32_si128((int)(L | (K << 8) | (J << 16) | (I << 24)));
+  const __m128i LKJIXABCD = _mm_or_si128(LKJI_____, ____XABCD);
+  const __m128i KJIXABCD_ = _mm_srli_si128(LKJIXABCD, 1);
+  const __m128i JIXABCD__ = _mm_srli_si128(LKJIXABCD, 2);
+  const __m128i avg1 = _mm_avg_epu8(JIXABCD__, LKJIXABCD);
+  const __m128i lsb = _mm_and_si128(_mm_xor_si128(JIXABCD__, LKJIXABCD), one);
+  const __m128i avg2 = _mm_subs_epu8(avg1, lsb);
+  const __m128i abcdefg = _mm_avg_epu8(avg2, KJIXABCD_);
+  WebPInt32ToMem(dst + 3 * BPS, _mm_cvtsi128_si32(               abcdefg    ));
+  WebPInt32ToMem(dst + 2 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 1)));
+  WebPInt32ToMem(dst + 1 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 2)));
+  WebPInt32ToMem(dst + 0 * BPS, _mm_cvtsi128_si32(_mm_srli_si128(abcdefg, 3)));
+}
+
+#undef DST
+#undef AVG3
+
+//------------------------------------------------------------------------------
+// Luma 16x16
+
+static WEBP_INLINE void TrueMotion_SSE2(uint8_t* dst, int size) {
+  const uint8_t* top = dst - BPS;
+  const __m128i zero = _mm_setzero_si128();
+  int y;
+  if (size == 4) {
+    const __m128i top_values = _mm_cvtsi32_si128(WebPMemToInt32(top));
+    const __m128i top_base = _mm_unpacklo_epi8(top_values, zero);
+    for (y = 0; y < 4; ++y, dst += BPS) {
+      const int val = dst[-1] - top[-1];
+      const __m128i base = _mm_set1_epi16(val);
+      const __m128i out = _mm_packus_epi16(_mm_add_epi16(base, top_base), zero);
+      WebPInt32ToMem(dst, _mm_cvtsi128_si32(out));
+    }
+  } else if (size == 8) {
+    const __m128i top_values = _mm_loadl_epi64((const __m128i*)top);
+    const __m128i top_base = _mm_unpacklo_epi8(top_values, zero);
+    for (y = 0; y < 8; ++y, dst += BPS) {
+      const int val = dst[-1] - top[-1];
+      const __m128i base = _mm_set1_epi16(val);
+      const __m128i out = _mm_packus_epi16(_mm_add_epi16(base, top_base), zero);
+      _mm_storel_epi64((__m128i*)dst, out);
+    }
+  } else {
+    const __m128i top_values = _mm_loadu_si128((const __m128i*)top);
+    const __m128i top_base_0 = _mm_unpacklo_epi8(top_values, zero);
+    const __m128i top_base_1 = _mm_unpackhi_epi8(top_values, zero);
+    for (y = 0; y < 16; ++y, dst += BPS) {
+      const int val = dst[-1] - top[-1];
+      const __m128i base = _mm_set1_epi16(val);
+      const __m128i out_0 = _mm_add_epi16(base, top_base_0);
+      const __m128i out_1 = _mm_add_epi16(base, top_base_1);
+      const __m128i out = _mm_packus_epi16(out_0, out_1);
+      _mm_storeu_si128((__m128i*)dst, out);
+    }
+  }
+}
+
+static void TM4_SSE2(uint8_t* dst)   { TrueMotion_SSE2(dst, 4); }
+static void TM8uv_SSE2(uint8_t* dst) { TrueMotion_SSE2(dst, 8); }
+static void TM16_SSE2(uint8_t* dst)  { TrueMotion_SSE2(dst, 16); }
+
+static void VE16_SSE2(uint8_t* dst) {
+  const __m128i top = _mm_loadu_si128((const __m128i*)(dst - BPS));
+  int j;
+  for (j = 0; j < 16; ++j) {
+    _mm_storeu_si128((__m128i*)(dst + j * BPS), top);
+  }
+}
+
+static void HE16_SSE2(uint8_t* dst) {     // horizontal
+  int j;
+  for (j = 16; j > 0; --j) {
+    const __m128i values = _mm_set1_epi8((char)dst[-1]);
+    _mm_storeu_si128((__m128i*)dst, values);
+    dst += BPS;
+  }
+}
+
+static WEBP_INLINE void Put16_SSE2(uint8_t v, uint8_t* dst) {
+  int j;
+  const __m128i values = _mm_set1_epi8((char)v);
+  for (j = 0; j < 16; ++j) {
+    _mm_storeu_si128((__m128i*)(dst + j * BPS), values);
+  }
+}
+
+static void DC16_SSE2(uint8_t* dst) {  // DC
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i top = _mm_loadu_si128((const __m128i*)(dst - BPS));
+  const __m128i sad8x2 = _mm_sad_epu8(top, zero);
+  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
+  const __m128i sum = _mm_add_epi16(sad8x2, _mm_shuffle_epi32(sad8x2, 2));
+  int left = 0;
+  int j;
+  for (j = 0; j < 16; ++j) {
+    left += dst[-1 + j * BPS];
+  }
+  {
+    const int DC = _mm_cvtsi128_si32(sum) + left + 16;
+    Put16_SSE2(DC >> 5, dst);
+  }
+}
+
+static void DC16NoTop_SSE2(uint8_t* dst) {  // DC with top samples unavailable
+  int DC = 8;
+  int j;
+  for (j = 0; j < 16; ++j) {
+    DC += dst[-1 + j * BPS];
+  }
+  Put16_SSE2(DC >> 4, dst);
+}
+
+static void DC16NoLeft_SSE2(uint8_t* dst) {  // DC with left samples unavailable
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i top = _mm_loadu_si128((const __m128i*)(dst - BPS));
+  const __m128i sad8x2 = _mm_sad_epu8(top, zero);
+  // sum the two sads: sad8x2[0:1] + sad8x2[8:9]
+  const __m128i sum = _mm_add_epi16(sad8x2, _mm_shuffle_epi32(sad8x2, 2));
+  const int DC = _mm_cvtsi128_si32(sum) + 8;
+  Put16_SSE2(DC >> 4, dst);
+}
+
+static void DC16NoTopLeft_SSE2(uint8_t* dst) {  // DC with no top & left samples
+  Put16_SSE2(0x80, dst);
+}
+
+//------------------------------------------------------------------------------
+// Chroma
+
+static void VE8uv_SSE2(uint8_t* dst) {    // vertical
+  int j;
+  const __m128i top = _mm_loadl_epi64((const __m128i*)(dst - BPS));
+  for (j = 0; j < 8; ++j) {
+    _mm_storel_epi64((__m128i*)(dst + j * BPS), top);
+  }
+}
+
+// helper for chroma-DC predictions
+static WEBP_INLINE void Put8x8uv_SSE2(uint8_t v, uint8_t* dst) {
+  int j;
+  const __m128i values = _mm_set1_epi8((char)v);
+  for (j = 0; j < 8; ++j) {
+    _mm_storel_epi64((__m128i*)(dst + j * BPS), values);
+  }
+}
+
+static void DC8uv_SSE2(uint8_t* dst) {     // DC
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i top = _mm_loadl_epi64((const __m128i*)(dst - BPS));
+  const __m128i sum = _mm_sad_epu8(top, zero);
+  int left = 0;
+  int j;
+  for (j = 0; j < 8; ++j) {
+    left += dst[-1 + j * BPS];
+  }
+  {
+    const int DC = _mm_cvtsi128_si32(sum) + left + 8;
+    Put8x8uv_SSE2(DC >> 4, dst);
+  }
+}
+
+static void DC8uvNoLeft_SSE2(uint8_t* dst) {   // DC with no left samples
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i top = _mm_loadl_epi64((const __m128i*)(dst - BPS));
+  const __m128i sum = _mm_sad_epu8(top, zero);
+  const int DC = _mm_cvtsi128_si32(sum) + 4;
+  Put8x8uv_SSE2(DC >> 3, dst);
+}
+
+static void DC8uvNoTop_SSE2(uint8_t* dst) {  // DC with no top samples
+  int dc0 = 4;
+  int i;
+  for (i = 0; i < 8; ++i) {
+    dc0 += dst[-1 + i * BPS];
+  }
+  Put8x8uv_SSE2(dc0 >> 3, dst);
+}
+
+static void DC8uvNoTopLeft_SSE2(uint8_t* dst) {    // DC with nothing
+  Put8x8uv_SSE2(0x80, dst);
+}
+
+//------------------------------------------------------------------------------
+// Entry point
+
+extern void VP8DspInitSSE2(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8DspInitSSE2(void) {
+  VP8Transform = Transform_SSE2;
+#if (USE_TRANSFORM_AC3 == 1)
+  VP8TransformAC3 = TransformAC3_SSE2;
+#endif
+
+  VP8VFilter16 = VFilter16_SSE2;
+  VP8HFilter16 = HFilter16_SSE2;
+  VP8VFilter8 = VFilter8_SSE2;
+  VP8HFilter8 = HFilter8_SSE2;
+  VP8VFilter16i = VFilter16i_SSE2;
+  VP8HFilter16i = HFilter16i_SSE2;
+  VP8VFilter8i = VFilter8i_SSE2;
+  VP8HFilter8i = HFilter8i_SSE2;
+
+  VP8SimpleVFilter16 = SimpleVFilter16_SSE2;
+  VP8SimpleHFilter16 = SimpleHFilter16_SSE2;
+  VP8SimpleVFilter16i = SimpleVFilter16i_SSE2;
+  VP8SimpleHFilter16i = SimpleHFilter16i_SSE2;
+
+  VP8PredLuma4[1] = TM4_SSE2;
+  VP8PredLuma4[2] = VE4_SSE2;
+  VP8PredLuma4[4] = RD4_SSE2;
+  VP8PredLuma4[5] = VR4_SSE2;
+  VP8PredLuma4[6] = LD4_SSE2;
+  VP8PredLuma4[7] = VL4_SSE2;
+
+  VP8PredLuma16[0] = DC16_SSE2;
+  VP8PredLuma16[1] = TM16_SSE2;
+  VP8PredLuma16[2] = VE16_SSE2;
+  VP8PredLuma16[3] = HE16_SSE2;
+  VP8PredLuma16[4] = DC16NoTop_SSE2;
+  VP8PredLuma16[5] = DC16NoLeft_SSE2;
+  VP8PredLuma16[6] = DC16NoTopLeft_SSE2;
+
+  VP8PredChroma8[0] = DC8uv_SSE2;
+  VP8PredChroma8[1] = TM8uv_SSE2;
+  VP8PredChroma8[2] = VE8uv_SSE2;
+  VP8PredChroma8[4] = DC8uvNoTop_SSE2;
+  VP8PredChroma8[5] = DC8uvNoLeft_SSE2;
+  VP8PredChroma8[6] = DC8uvNoTopLeft_SSE2;
+}
+
+#else  // !WEBP_USE_SSE2
+
+WEBP_DSP_INIT_STUB(VP8DspInitSSE2)
+
+#endif  // WEBP_USE_SSE2