Created
May 21, 2014 21:12
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"Simple function to round up to the next power of 2"
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| //############################################################################ | |
| //## ## | |
| //## Simple function to round up to the next power of 2. ## | |
| //## ## | |
| //############################################################################ | |
| static U32 Round_up_to_next_2_power( U32 value ) | |
| { | |
| if ( value > 16 ) | |
| if ( value > 64 ) | |
| if ( value > 128 ) | |
| if ( value > 256 ) | |
| if ( value > 512 ) | |
| return( 1024 ); | |
| else | |
| return( 512 ); | |
| else | |
| return( 256 ); | |
| else | |
| return( 128 ); | |
| else | |
| if ( value > 32 ) | |
| return( 64 ); | |
| else | |
| return( 32 ); | |
| else | |
| if ( value > 4 ) | |
| if ( value > 8 ) | |
| return( 16 ); | |
| else | |
| return( 8 ); | |
| else | |
| if ( value > 2 ) | |
| return( 4 ); | |
| return( value ); | |
| } |
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From Hacker's Delight: (branchless)
static uint32_t Round_up_to_next_2_power(uint32_t x)
{
x = x - 1;
x = x | (x >> 1);
x = x | (x >> 2);
x = x | (x >> 4);
x = x | (x >> 8);
x = x | (x >> 16);
}