1 // Reverse the bit order in a 32-bit word. 2 unsigned int rbit( 3 unsigned int i ) 4 { 5 i = ( ( i & 0x55555555 ) << 1 ) | ( ( i >> 1 ) & 0x55555555 ); 6 i = ( ( i & 0x33333333 ) << 2 ) | ( ( i >> 2 ) & 0x33333333 ); 7 i = ( ( i & 0x0f0f0f0f ) << 4 ) | ( ( i >> 4 ) & 0x0f0f0f0f ); 8 i = ( i << 24 ) | ( ( i & 0xff00 ) << 8 ) // 9 | ( ( i >> 8 ) & 0xff00 ) | ( i >> 24 ); 10 return i; 11 } 12 13 // Reverse byte order in each halfword independently 14 // converts 16-bit big-endian data into little-endian data 15 // or 16-bit little-endian data into big-endian data 16 short rev16( 17 short s ) 18 { 19 return ( s << 8 ) | ( s >> 8 ); 20 } 21 22 // Reverse byte order in a word 23 // converts 32-bit big-endian data into little-endian data 24 // or 32-bit little-endian data into big-endian data. 25 unsigned int rev( 26 unsigned int i ) 27 { 28 return ( i & 0x000000FFU ) << 24 | ( i & 0x0000FF00U ) << 8 29 | ( i & 0x00FF0000U ) >> 8 | ( i & 0xFF000000U ) >> 24; 30 }