commit 13c7715a75e91bcd855e0aa647ecd88d90152e63
author A.Mahfoodh <ab.mahfoodh@gmail.com> Mon Sep 23 14:13:40 2013 -0400
committer Johann <johann.koenig@duck.com> Mon Sep 23 17:23:27 2013 -0700
tree 63b6923e72084cc78dada44e03b86d49e6fb8db8
parent 54c87058bfa5124408f0725deb8373ef94c4b98e

Number of instructions in fdct4_1d_sse2 reduced by two.

Mathematically the results are the same.

Change-Id: I1c5126cd3ca64e8515ca6331e0989c6f7dd651a0

vp9/encoder/x86/vp9_dct_sse2.c

diff --git a/vp9/encoder/x86/vp9_dct_sse2.c b/vp9/encoder/x86/vp9_dct_sse2.c
index eb271fe..ad3d01d 100644
--- a/vp9/encoder/x86/vp9_dct_sse2.c
+++ b/vp9/encoder/x86/vp9_dct_sse2.c
@@ -171,22 +171,21 @@
 void fdct4_1d_sse2(__m128i *in) {
   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_m08_p24 = pair_set_epi16(-cospi_8_64, cospi_24_64);
+  const __m128i k__cospi_p08_p24 = pair_set_epi16(cospi_8_64, cospi_24_64);
+  const __m128i k__cospi_p24_m08 = pair_set_epi16(cospi_24_64, -cospi_8_64);
   const __m128i k__DCT_CONST_ROUNDING = _mm_set1_epi32(DCT_CONST_ROUNDING);
 
   __m128i u[4], v[4];
-  u[0] = _mm_add_epi16(in[0], in[3]);
-  u[1] = _mm_add_epi16(in[1], in[2]);
-  u[2] = _mm_sub_epi16(in[1], in[2]);
-  u[3] = _mm_sub_epi16(in[0], in[3]);
+  u[0]=_mm_unpacklo_epi16(in[0], in[1]);
+  u[1]=_mm_unpacklo_epi16(in[3], in[2]);
 
-  v[0] = _mm_unpacklo_epi16(u[0], u[1]);
-  v[1] = _mm_unpacklo_epi16(u[2], u[3]);
+  v[0] = _mm_add_epi16(u[0], u[1]);
+  v[1] = _mm_sub_epi16(u[0], u[1]);
+
   u[0] = _mm_madd_epi16(v[0], k__cospi_p16_p16);  // 0
   u[1] = _mm_madd_epi16(v[0], k__cospi_p16_m16);  // 2
-  u[2] = _mm_madd_epi16(v[1], k__cospi_p24_p08);  // 1
-  u[3] = _mm_madd_epi16(v[1], k__cospi_m08_p24);  // 3
+  u[2] = _mm_madd_epi16(v[1], k__cospi_p08_p24);  // 1
+  u[3] = _mm_madd_epi16(v[1], k__cospi_p24_m08);  // 3
 
   v[0] = _mm_add_epi32(u[0], k__DCT_CONST_ROUNDING);
   v[1] = _mm_add_epi32(u[1], k__DCT_CONST_ROUNDING);