ref: 37798711aad7792d9067c80768e5188ecf63ccd3
parent: b46243d7ff0f0d02d66010fb7830bb767046508b
parent: ab0e7a237a6e9796c15a8858caac04dea3593d62
author: Johann Koenig <[email protected]>
date: Mon Sep 26 15:10:57 EDT 2016
Merge "Use shifted value for sinpi8sqrt2"
--- a/test/idct_test.cc
+++ b/test/idct_test.cc
@@ -115,6 +115,10 @@
}
INSTANTIATE_TEST_CASE_P(C, IDCTTest, ::testing::Values(vp8_short_idct4x4llm_c));
+#if HAVE_NEON
+INSTANTIATE_TEST_CASE_P(NEON, IDCTTest,
+ ::testing::Values(vp8_short_idct4x4llm_neon));
+#endif
#if HAVE_MMX
INSTANTIATE_TEST_CASE_P(MMX, IDCTTest,
::testing::Values(vp8_short_idct4x4llm_mmx));
--- a/vp8/common/arm/neon/dequant_idct_neon.c
+++ b/vp8/common/arm/neon/dequant_idct_neon.c
@@ -11,7 +11,11 @@
#include <arm_neon.h>
static const int16_t cospi8sqrt2minus1 = 20091;
-static const int16_t sinpi8sqrt2 = 35468;
+// 35468 exceeds INT16_MAX and gets converted to a negative number. Because of
+// the way it is used in vqdmulh, where the result is doubled, it can be divided
+// by 2 beforehand. This saves compensating for the negative value as well as
+// shifting the result.
+static const int16_t sinpi8sqrt2 = 35468 >> 1;
void vp8_dequant_idct_add_neon(int16_t *input, int16_t *dq, unsigned char *dst,
int stride) {@@ -60,10 +64,8 @@
q3 = vqdmulhq_n_s16(q2, sinpi8sqrt2);
q4 = vqdmulhq_n_s16(q2, cospi8sqrt2minus1);
- q3 = vshrq_n_s16(q3, 1);
q4 = vshrq_n_s16(q4, 1);
- q3 = vqaddq_s16(q3, q2);
q4 = vqaddq_s16(q4, q2);
d10 = vqsub_s16(vget_low_s16(q3), vget_high_s16(q4));
@@ -90,10 +92,8 @@
d12 = vqadd_s16(d2tmp2.val[0], d2tmp3.val[0]);
d13 = vqsub_s16(d2tmp2.val[0], d2tmp3.val[0]);
- q3 = vshrq_n_s16(q3, 1);
q4 = vshrq_n_s16(q4, 1);
- q3 = vqaddq_s16(q3, q2);
q4 = vqaddq_s16(q4, q2);
d10 = vqsub_s16(vget_low_s16(q3), vget_high_s16(q4));
--- a/vp8/common/arm/neon/shortidct4x4llm_neon.c
+++ b/vp8/common/arm/neon/shortidct4x4llm_neon.c
@@ -11,7 +11,11 @@
#include <arm_neon.h>
static const int16_t cospi8sqrt2minus1 = 20091;
-static const int16_t sinpi8sqrt2 = 35468;
+// 35468 exceeds INT16_MAX and gets converted to a negative number. Because of
+// the way it is used in vqdmulh, where the result is doubled, it can be divided
+// by 2 beforehand. This saves compensating for the negative value as well as
+// shifting the result.
+static const int16_t sinpi8sqrt2 = 35468 >> 1;
void vp8_short_idct4x4llm_neon(int16_t *input, unsigned char *pred_ptr,
int pred_stride, unsigned char *dst_ptr,
@@ -40,10 +44,8 @@
d12 = vqadd_s16(vget_low_s16(q1s16), vget_high_s16(q1s16)); // a1
d13 = vqsub_s16(vget_low_s16(q1s16), vget_high_s16(q1s16)); // b1
- q3s16 = vshrq_n_s16(q3s16, 1);
q4s16 = vshrq_n_s16(q4s16, 1);
- q3s16 = vqaddq_s16(q3s16, q2s16);
q4s16 = vqaddq_s16(q4s16, q2s16);
d10 = vqsub_s16(vget_low_s16(q3s16), vget_high_s16(q4s16)); // c1
@@ -71,10 +73,8 @@
d12 = vqadd_s16(vget_low_s16(q1s16), vget_high_s16(q1s16)); // a1
d13 = vqsub_s16(vget_low_s16(q1s16), vget_high_s16(q1s16)); // b1
- q3s16 = vshrq_n_s16(q3s16, 1);
q4s16 = vshrq_n_s16(q4s16, 1);
- q3s16 = vqaddq_s16(q3s16, q2s16);
q4s16 = vqaddq_s16(q4s16, q2s16);
d10 = vqsub_s16(vget_low_s16(q3s16), vget_high_s16(q4s16)); // c1