tree 4896458f242a78ed4c1ec7977af003f64305830f
parent 4137f7daaa1c3947bba45681a4ff32142ca3097d
author Wan-Teh Chang <wtc@google.com> 1534440713 -0700
committer Wan-Teh Chang <wtc@google.com> 1536344237 +0000

Pass n to get_msb in the primitive_quniform funcs.

The functions this CL modifies were added in the following two CLs:
https://aomedia-review.googlesource.com/c/aom/+/8789
https://aomedia-review.googlesource.com/c/aom/+/20820

These functions pass n - 1 to get_msb(). I believe these functions
implement the ns(n) and NS(n) descriptors of the AV1 spec. ns(n) and
NS(n) pass n, not n - 1, to FloorLog2(). (FloorLog2() is the same as
libaom's get_msb() function.)

A careful analysis of the code shows passing n instead of n - 1 to
get_msb() results in the same outcome for these functions. Passing n
matches the AV1 spec and is slightly more efficient when n is a power
of 2.

Change-Id: Ibeff837059e9c9de2b4ab9cb857a2ea60b1c4767