commit bbcd8f7663b49c08791c898d605d47e2c26b1aa6
author Angie Chiang <angiebird@google.com> Wed Oct 04 16:20:10 2017 -0700
committer Angie Chiang <angiebird@google.com> Fri Oct 06 22:53:02 2017 +0000
tree 38d3ca32bbdc5a607d4dca078b9d7d50dd93a724
parent 92acb81b0189c622e9b179abcb418188df033d6e

Reduce division operations in update_scan_prob

Change-Id: I923931a9dbf828eb13670511852d55c953b479c1

av1/common/scan.c

diff --git a/av1/common/scan.c b/av1/common/scan.c
index c6e3b40..34a8595 100644
--- a/av1/common/scan.c
+++ b/av1/common/scan.c
@@ -8208,11 +8208,12 @@
   }
 #endif
   int i;
+  const int inv_precision = 30;
+  int32_t inv_block_num = block_num == 0 ? 0 : (1 << inv_precision) / block_num;
   for (i = 0; i < tx2d_size; i++) {
     int64_t curr_prob =
-        block_num == 0
-            ? 0
-            : (non_zero_count[i] << ADAPT_SCAN_PROB_PRECISION) / block_num;
+        block_num == 0 ? 0 : ((non_zero_count[i] * inv_block_num) >>
+                              (inv_precision - ADAPT_SCAN_PROB_PRECISION));
     int64_t prev_prob = prev_non_zero_prob[i];
     int64_t pred_prob =
         (curr_prob * rate +