Adjust the forward 16x16 DCT computation steps

This commit adjusts the forward 16x16 DCT computation steps to
simplify the register level operations. It fixes the corresponding
sse2 version accordingly.

Change-Id: I72a9c25b8ca9442fc5e113f47cd701ae55aa7f08

2 files changed, 30 insertions, 30 deletions

diff --git a/vp9/encoder/vp9_dct.c b/vp9/encoder/vp9_dct.c
index d5232393f..577276764 100644
--- a/vp9/encoder/vp9_dct.c
+++ b/vp9/encoder/vp9_dct.c
@@ -445,20 +445,20 @@ void vp9_fdct16x16_c(const int16_t *input, int16_t *output, int stride) {
         step3[7] = step1[7] + step2[4];
         // step 4
         temp1 = step3[1] *  -cospi_8_64 + step3[6] * cospi_24_64;
-        temp2 = step3[2] * -cospi_24_64 - step3[5] *  cospi_8_64;
+        temp2 = step3[2] * cospi_24_64 + step3[5] *  cospi_8_64;
         step2[1] = fdct_round_shift(temp1);
         step2[2] = fdct_round_shift(temp2);
-        temp1 = step3[2] * -cospi_8_64 + step3[5] * cospi_24_64;
+        temp1 = step3[2] * cospi_8_64 - step3[5] * cospi_24_64;
         temp2 = step3[1] * cospi_24_64 + step3[6] *  cospi_8_64;
         step2[5] = fdct_round_shift(temp1);
         step2[6] = fdct_round_shift(temp2);
         // step 5
         step1[0] = step3[0] + step2[1];
         step1[1] = step3[0] - step2[1];
-        step1[2] = step3[3] - step2[2];
-        step1[3] = step3[3] + step2[2];
-        step1[4] = step3[4] + step2[5];
-        step1[5] = step3[4] - step2[5];
+        step1[2] = step3[3] + step2[2];
+        step1[3] = step3[3] - step2[2];
+        step1[4] = step3[4] - step2[5];
+        step1[5] = step3[4] + step2[5];
         step1[6] = step3[7] - step2[6];
         step1[7] = step3[7] + step2[6];
         // step 6
@@ -755,10 +755,10 @@ static void fdct16(const int16_t in[16], int16_t out[16]) {
 
   // step 4
   temp1 = step3[1] *  -cospi_8_64 + step3[6] * cospi_24_64;
-  temp2 = step3[2] * -cospi_24_64 - step3[5] *  cospi_8_64;
+  temp2 = step3[2] * cospi_24_64 + step3[5] *  cospi_8_64;
   step2[1] = fdct_round_shift(temp1);
   step2[2] = fdct_round_shift(temp2);
-  temp1 = step3[2] * -cospi_8_64 + step3[5] * cospi_24_64;
+  temp1 = step3[2] * cospi_8_64 - step3[5] * cospi_24_64;
   temp2 = step3[1] * cospi_24_64 + step3[6] *  cospi_8_64;
   step2[5] = fdct_round_shift(temp1);
   step2[6] = fdct_round_shift(temp2);
@@ -766,10 +766,10 @@ static void fdct16(const int16_t in[16], int16_t out[16]) {
   // step 5
   step1[0] = step3[0] + step2[1];
   step1[1] = step3[0] - step2[1];
-  step1[2] = step3[3] - step2[2];
-  step1[3] = step3[3] + step2[2];
-  step1[4] = step3[4] + step2[5];
-  step1[5] = step3[4] - step2[5];
+  step1[2] = step3[3] + step2[2];
+  step1[3] = step3[3] - step2[2];
+  step1[4] = step3[4] - step2[5];
+  step1[5] = step3[4] + step2[5];
   step1[6] = step3[7] - step2[6];
   step1[7] = step3[7] + step2[6];
 
diff --git a/vp9/encoder/x86/vp9_dct_sse2.c b/vp9/encoder/x86/vp9_dct_sse2.c
index 686582238..1f58d872e 100644
--- a/vp9/encoder/x86/vp9_dct_sse2.c
+++ b/vp9/encoder/x86/vp9_dct_sse2.c
@@ -1187,7 +1187,7 @@ void vp9_fdct16x16_sse2(const int16_t *input, int16_t *output, int stride) {
   const __m128i k__cospi_p16_p16 = _mm_set1_epi16(cospi_16_64);
   const __m128i k__cospi_p16_m16 = pair_set_epi16(cospi_16_64, -cospi_16_64);
   const __m128i k__cospi_p24_p08 = pair_set_epi16(cospi_24_64, cospi_8_64);
-  const __m128i k__cospi_m24_m08 = pair_set_epi16(-cospi_24_64, -cospi_8_64);
+  const __m128i k__cospi_p08_m24 = pair_set_epi16(cospi_8_64, -cospi_24_64);
   const __m128i k__cospi_m08_p24 = pair_set_epi16(-cospi_8_64, cospi_24_64);
   const __m128i k__cospi_p28_p04 = pair_set_epi16(cospi_28_64, cospi_4_64);
   const __m128i k__cospi_m04_p28 = pair_set_epi16(-cospi_4_64, cospi_28_64);
@@ -1513,8 +1513,8 @@ void vp9_fdct16x16_sse2(const int16_t *input, int16_t *output, int stride) {
           const __m128i t3 = _mm_unpackhi_epi16(step3_2, step3_5);
           const __m128i u0 = _mm_madd_epi16(t0, k__cospi_m08_p24);
           const __m128i u1 = _mm_madd_epi16(t1, k__cospi_m08_p24);
-          const __m128i u2 = _mm_madd_epi16(t2, k__cospi_m24_m08);
-          const __m128i u3 = _mm_madd_epi16(t3, k__cospi_m24_m08);
+          const __m128i u2 = _mm_madd_epi16(t2, k__cospi_p24_p08);
+          const __m128i u3 = _mm_madd_epi16(t3, k__cospi_p24_p08);
           // dct_const_round_shift
           const __m128i v0 = _mm_add_epi32(u0, k__DCT_CONST_ROUNDING);
           const __m128i v1 = _mm_add_epi32(u1, k__DCT_CONST_ROUNDING);
@@ -1535,8 +1535,8 @@ void vp9_fdct16x16_sse2(const int16_t *input, int16_t *output, int stride) {
           const __m128i t3 = _mm_unpackhi_epi16(step3_2, step3_5);
           const __m128i u0 = _mm_madd_epi16(t0, k__cospi_p24_p08);
           const __m128i u1 = _mm_madd_epi16(t1, k__cospi_p24_p08);
-          const __m128i u2 = _mm_madd_epi16(t2, k__cospi_m08_p24);
-          const __m128i u3 = _mm_madd_epi16(t3, k__cospi_m08_p24);
+          const __m128i u2 = _mm_madd_epi16(t2, k__cospi_p08_m24);
+          const __m128i u3 = _mm_madd_epi16(t3, k__cospi_p08_m24);
           // dct_const_round_shift
           const __m128i v0 = _mm_add_epi32(u0, k__DCT_CONST_ROUNDING);
           const __m128i v1 = _mm_add_epi32(u1, k__DCT_CONST_ROUNDING);
@@ -1554,10 +1554,10 @@ void vp9_fdct16x16_sse2(const int16_t *input, int16_t *output, int stride) {
         {
           step1_0 = _mm_add_epi16(step3_0, step2_1);
           step1_1 = _mm_sub_epi16(step3_0, step2_1);
-          step1_2 = _mm_sub_epi16(step3_3, step2_2);
-          step1_3 = _mm_add_epi16(step3_3, step2_2);
-          step1_4 = _mm_add_epi16(step3_4, step2_5);
-          step1_5 = _mm_sub_epi16(step3_4, step2_5);
+          step1_2 = _mm_add_epi16(step3_3, step2_2);
+          step1_3 = _mm_sub_epi16(step3_3, step2_2);
+          step1_4 = _mm_sub_epi16(step3_4, step2_5);
+          step1_5 = _mm_add_epi16(step3_4, step2_5);
           step1_6 = _mm_sub_epi16(step3_7, step2_6);
           step1_7 = _mm_add_epi16(step3_7, step2_6);
         }
@@ -1848,7 +1848,7 @@ void fdct16_8col(__m128i *in) {
   const __m128i k__cospi_p16_m16 = pair_set_epi16(cospi_16_64, -cospi_16_64);
   const __m128i k__cospi_m16_p16 = pair_set_epi16(-cospi_16_64, cospi_16_64);
   const __m128i k__cospi_p24_p08 = pair_set_epi16(cospi_24_64, cospi_8_64);
-  const __m128i k__cospi_m24_m08 = pair_set_epi16(-cospi_24_64, -cospi_8_64);
+  const __m128i k__cospi_p08_m24 = pair_set_epi16(cospi_8_64, -cospi_24_64);
   const __m128i k__cospi_m08_p24 = pair_set_epi16(-cospi_8_64, cospi_24_64);
   const __m128i k__cospi_p28_p04 = pair_set_epi16(cospi_28_64, cospi_4_64);
   const __m128i k__cospi_m04_p28 = pair_set_epi16(-cospi_4_64, cospi_28_64);
@@ -2052,10 +2052,10 @@ void fdct16_8col(__m128i *in) {
 
   v[0] = _mm_madd_epi16(u[0], k__cospi_m08_p24);
   v[1] = _mm_madd_epi16(u[1], k__cospi_m08_p24);
-  v[2] = _mm_madd_epi16(u[2], k__cospi_m24_m08);
-  v[3] = _mm_madd_epi16(u[3], k__cospi_m24_m08);
-  v[4] = _mm_madd_epi16(u[2], k__cospi_m08_p24);
-  v[5] = _mm_madd_epi16(u[3], k__cospi_m08_p24);
+  v[2] = _mm_madd_epi16(u[2], k__cospi_p24_p08);
+  v[3] = _mm_madd_epi16(u[3], k__cospi_p24_p08);
+  v[4] = _mm_madd_epi16(u[2], k__cospi_p08_m24);
+  v[5] = _mm_madd_epi16(u[3], k__cospi_p08_m24);
   v[6] = _mm_madd_epi16(u[0], k__cospi_p24_p08);
   v[7] = _mm_madd_epi16(u[1], k__cospi_p24_p08);
 
@@ -2085,10 +2085,10 @@ void fdct16_8col(__m128i *in) {
   // stage 5
   s[0] = _mm_add_epi16(p[0], t[1]);
   s[1] = _mm_sub_epi16(p[0], t[1]);
-  s[2] = _mm_sub_epi16(p[3], t[2]);
-  s[3] = _mm_add_epi16(p[3], t[2]);
-  s[4] = _mm_add_epi16(p[4], t[5]);
-  s[5] = _mm_sub_epi16(p[4], t[5]);
+  s[2] = _mm_add_epi16(p[3], t[2]);
+  s[3] = _mm_sub_epi16(p[3], t[2]);
+  s[4] = _mm_sub_epi16(p[4], t[5]);
+  s[5] = _mm_add_epi16(p[4], t[5]);
   s[6] = _mm_sub_epi16(p[7], t[6]);
   s[7] = _mm_add_epi16(p[7], t[6]);