Replace divide with look-up
This commit replaces an integer divide with a table-lookup. It is
to improve decoding speed, and at the same time, to reduce possible
complications with a bug in AMD Family 12h processors:
"665 Integer Divide Instruction May Cause Unpredictable Behavior"
Change-Id: I678b707a538798a923850bac467e66e847e6def7
diff --git a/vp9/common/vp9_prob.c b/vp9/common/vp9_prob.c
index a1befc6..3b7b9bf 100644
--- a/vp9/common/vp9_prob.c
+++ b/vp9/common/vp9_prob.c
@@ -29,33 +29,25 @@
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};
-
static unsigned int tree_merge_probs_impl(unsigned int i,
const vp9_tree_index *tree,
const vp9_prob *pre_probs,
const unsigned int *counts,
- unsigned int count_sat,
- unsigned int max_update,
vp9_prob *probs) {
const int l = tree[i];
const unsigned int left_count = (l <= 0)
? counts[-l]
- : tree_merge_probs_impl(l, tree, pre_probs, counts,
- count_sat, max_update, probs);
+ : tree_merge_probs_impl(l, tree, pre_probs, counts, probs);
const int r = tree[i + 1];
const unsigned int right_count = (r <= 0)
? counts[-r]
- : tree_merge_probs_impl(r, tree, pre_probs, counts,
- count_sat, max_update, probs);
+ : tree_merge_probs_impl(r, tree, pre_probs, counts, probs);
const unsigned int ct[2] = { left_count, right_count };
- probs[i >> 1] = merge_probs(pre_probs[i >> 1], ct,
- count_sat, max_update);
+ probs[i >> 1] = mode_mv_merge_probs(pre_probs[i >> 1], ct);
return left_count + right_count;
}
void vp9_tree_merge_probs(const vp9_tree_index *tree, const vp9_prob *pre_probs,
- const unsigned int *counts, unsigned int count_sat,
- unsigned int max_update_factor, vp9_prob *probs) {
- tree_merge_probs_impl(0, tree, pre_probs, counts, count_sat,
- max_update_factor, probs);
+ const unsigned int *counts, vp9_prob *probs) {
+ tree_merge_probs_impl(0, tree, pre_probs, counts, probs);
}
