better unrolled ver

This commit is contained in:
lizzie
2026-01-26 06:00:25 +00:00
committed by crueter
parent 144e20800f
commit 7d591b3bd9

View File

@@ -589,10 +589,13 @@ static TexelWeightParams DecodeBlockInfo(InputBitStream& strm) {
// Replicates low num_bits such that [(to_bit - 1):(to_bit - 1 - from_bit)]
// is the same as [(num_bits - 1):0] and repeats all the way down.
// to_bit range is expected from 0 to 8
// num_bits range is from 0 to 7
[[nodiscard]] constexpr u32 Replicate(u32 v, u32 num_bits, u32 to_bit) {
auto val = v;
for (; num_bits < to_bit; num_bits <<= 1)
val |= val << u32(num_bits);
auto val = v & ((1 << num_bits) - 1);
val |= val << (num_bits << 0);
val |= val << (num_bits << 1);
val |= val << (num_bits << 2);
auto const val_mask = u32(1 << to_bit) - 1;
return (v & ~val_mask) | (val & val_mask);
}