move the SSIM calculation code in ssim.c / ssim_sse2.c

Change-Id: I63a63fa7f44f257f2e17e45358b206c23069c448

src/dsp/ssim_sse2.c

@@ -0,0 +1,154 @@
+// Copyright 2017 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 distortion calculation
+//
+// Author: Skal (pascal.massimino@gmail.com)
+
+#include "./dsp.h"
+
+#if defined(WEBP_USE_SSE2)
+
+#include <assert.h>
+#include <emmintrin.h>
+
+#include "./common_sse2.h"
+
+// Helper function
+static WEBP_INLINE void SubtractAndSquare(const __m128i a, const __m128i b,
+                                          __m128i* const sum) {
+  // take abs(a-b) in 8b
+  const __m128i a_b = _mm_subs_epu8(a, b);
+  const __m128i b_a = _mm_subs_epu8(b, a);
+  const __m128i abs_a_b = _mm_or_si128(a_b, b_a);
+  // zero-extend to 16b
+  const __m128i zero = _mm_setzero_si128();
+  const __m128i C0 = _mm_unpacklo_epi8(abs_a_b, zero);
+  const __m128i C1 = _mm_unpackhi_epi8(abs_a_b, zero);
+  // multiply with self
+  const __m128i sum1 = _mm_madd_epi16(C0, C0);
+  const __m128i sum2 = _mm_madd_epi16(C1, C1);
+  *sum = _mm_add_epi32(sum1, sum2);
+}
+
+//------------------------------------------------------------------------------
+// SSIM / PSNR entry point
+
+static uint32_t AccumulateSSE_SSE2(const uint8_t* src1,
+                                   const uint8_t* src2, int len) {
+  int i = 0;
+  uint32_t sse2 = 0;
+  if (len >= 16) {
+    const int limit = len - 32;
+    int32_t tmp[4];
+    __m128i sum1;
+    __m128i sum = _mm_setzero_si128();
+    __m128i a0 = _mm_loadu_si128((const __m128i*)&src1[i]);
+    __m128i b0 = _mm_loadu_si128((const __m128i*)&src2[i]);
+    i += 16;
+    while (i <= limit) {
+      const __m128i a1 = _mm_loadu_si128((const __m128i*)&src1[i]);
+      const __m128i b1 = _mm_loadu_si128((const __m128i*)&src2[i]);
+      __m128i sum2;
+      i += 16;
+      SubtractAndSquare(a0, b0, &sum1);
+      sum = _mm_add_epi32(sum, sum1);
+      a0 = _mm_loadu_si128((const __m128i*)&src1[i]);
+      b0 = _mm_loadu_si128((const __m128i*)&src2[i]);
+      i += 16;
+      SubtractAndSquare(a1, b1, &sum2);
+      sum = _mm_add_epi32(sum, sum2);
+    }
+    SubtractAndSquare(a0, b0, &sum1);
+    sum = _mm_add_epi32(sum, sum1);
+    _mm_storeu_si128((__m128i*)tmp, sum);
+    sse2 += (tmp[3] + tmp[2] + tmp[1] + tmp[0]);
+  }
+
+  for (; i < len; ++i) {
+    const int32_t diff = src1[i] - src2[i];
+    sse2 += diff * diff;
+  }
+  return sse2;
+}
+
+static uint32_t HorizontalAdd16b(const __m128i* const m) {
+  uint16_t tmp[8];
+  const __m128i a = _mm_srli_si128(*m, 8);
+  const __m128i b = _mm_add_epi16(*m, a);
+  _mm_storeu_si128((__m128i*)tmp, b);
+  return (uint32_t)tmp[3] + tmp[2] + tmp[1] + tmp[0];
+}
+
+static uint32_t HorizontalAdd32b(const __m128i* const m) {
+  const __m128i a = _mm_srli_si128(*m, 8);
+  const __m128i b = _mm_add_epi32(*m, a);
+  const __m128i c = _mm_add_epi32(b, _mm_srli_si128(b, 4));
+  return (uint32_t)_mm_cvtsi128_si32(c);
+}
+
+static const uint16_t kWeight[] = { 1, 2, 3, 4, 3, 2, 1, 0 };
+
+#define ACCUMULATE_ROW(WEIGHT) do {                         \
+  /* compute row weight (Wx * Wy) */                        \
+  const __m128i Wy = _mm_set1_epi16((WEIGHT));              \
+  const __m128i W = _mm_mullo_epi16(Wx, Wy);                \
+  /* process 8 bytes at a time (7 bytes, actually) */       \
+  const __m128i a0 = _mm_loadl_epi64((const __m128i*)src1); \
+  const __m128i b0 = _mm_loadl_epi64((const __m128i*)src2); \
+  /* convert to 16b and multiply by weight */               \
+  const __m128i a1 = _mm_unpacklo_epi8(a0, zero);           \
+  const __m128i b1 = _mm_unpacklo_epi8(b0, zero);           \
+  const __m128i wa1 = _mm_mullo_epi16(a1, W);               \
+  const __m128i wb1 = _mm_mullo_epi16(b1, W);               \
+  /* accumulate */                                          \
+  xm  = _mm_add_epi16(xm, wa1);                             \
+  ym  = _mm_add_epi16(ym, wb1);                             \
+  xxm = _mm_add_epi32(xxm, _mm_madd_epi16(a1, wa1));        \
+  xym = _mm_add_epi32(xym, _mm_madd_epi16(a1, wb1));        \
+  yym = _mm_add_epi32(yym, _mm_madd_epi16(b1, wb1));        \
+  src1 += stride1;                                          \
+  src2 += stride2;                                          \
+} while (0)
+
+static double SSIMGet_SSE2(const uint8_t* src1, int stride1,
+                           const uint8_t* src2, int stride2) {
+  VP8DistoStats stats;
+  const __m128i zero = _mm_setzero_si128();
+  __m128i xm = zero, ym = zero;                // 16b accums
+  __m128i xxm = zero, yym = zero, xym = zero;  // 32b accum
+  const __m128i Wx = _mm_loadu_si128((const __m128i*)kWeight);
+  assert(2 * VP8_SSIM_KERNEL + 1 == 7);
+  ACCUMULATE_ROW(1);
+  ACCUMULATE_ROW(2);
+  ACCUMULATE_ROW(3);
+  ACCUMULATE_ROW(4);
+  ACCUMULATE_ROW(3);
+  ACCUMULATE_ROW(2);
+  ACCUMULATE_ROW(1);
+  stats.xm  = HorizontalAdd16b(&xm);
+  stats.ym  = HorizontalAdd16b(&ym);
+  stats.xxm = HorizontalAdd32b(&xxm);
+  stats.xym = HorizontalAdd32b(&xym);
+  stats.yym = HorizontalAdd32b(&yym);
+  return VP8SSIMFromStats(&stats);
+}
+
+extern void VP8SSIMDspInitSSE2(void);
+
+WEBP_TSAN_IGNORE_FUNCTION void VP8SSIMDspInitSSE2(void) {
+  VP8AccumulateSSE = AccumulateSSE_SSE2;
+  VP8SSIMGet = SSIMGet_SSE2;
+}
+
+#else  // !WEBP_USE_SSE2
+
+WEBP_DSP_INIT_STUB(VP8SSIMDspInitSSE2)
+
+#endif  // WEBP_USE_SSE2