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fast_log2: silence unused variable warning.

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Ion Gaztañaga
2021-03-14 08:15:33 +01:00
parent 45d6e4ee18
commit c03b16b269
1 changed files with 2 additions and 3 deletions
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5
include/boost/intrusive/detail/math.hpp
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@@ -209,13 +209,12 @@ namespace detail {
//http://www.flipcode.com/archives/Fast_log_Function.shtml //http://www.flipcode.com/archives/Fast_log_Function.shtml
inline float fast_log2 (float val) inline float fast_log2 (float val)
{ {
float f = val;
unsigned x; unsigned x;
std::memcpy(&x, &val, sizeof(f)); std::memcpy(&x, &val, sizeof(float));
const int log_2 = int((x >> 23) & 255) - 128; const int log_2 = int((x >> 23) & 255) - 128;
x &= ~(unsigned(255u) << 23u); x &= ~(unsigned(255u) << 23u);
x += unsigned(127) << 23u; x += unsigned(127) << 23u;
std::memcpy(&val, &x, sizeof(f)); std::memcpy(&val, &x, sizeof(float));
//1+log2(m), m ranging from 1 to 2 //1+log2(m), m ranging from 1 to 2
//3rd degree polynomial keeping first derivate continuity. //3rd degree polynomial keeping first derivate continuity.
//For less precision the line can be commented out //For less precision the line can be commented out