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extended integer math with log2(uint8_t)

tagfs
Ludovic 'Archivist' Lagouardette 4 years ago
parent
commit
4423a883e9
1 changed files with 15 additions and 0 deletions
  1. +15
    -0
      include/gp/math/integer_math.hpp

+ 15
- 0
include/gp/math/integer_math.hpp View File

@ -13,6 +13,21 @@ namespace gp {
Sean Eron Anderson Sean Eron Anderson
seander@cs.stanford.edu seander@cs.stanford.edu
**/ **/
template<>
constexpr size_t log2<uint8_t>(uint8_t v)
{
constexpr int MultiplyDeBruijnBitPosition[8] =
{
0, 5, 1, 6, 4, 3, 2, 7
};
v |= v >> 1;
v |= v >> 2;
v |= v >> 4;
return MultiplyDeBruijnBitPosition[(v * 29U) >> 5];
}
template<> template<>
constexpr size_t log2<uint32_t>(uint32_t v) constexpr size_t log2<uint32_t>(uint32_t v)
{ {

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