diff options
Diffstat (limited to 'src/utils/bit_ops.h')
| -rw-r--r-- | src/utils/bit_ops.h | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/src/utils/bit_ops.h b/src/utils/bit_ops.h index c02ec536f..36bac9f73 100644 --- a/src/utils/bit_ops.h +++ b/src/utils/bit_ops.h @@ -12,9 +12,10 @@ namespace Botan { -/* -* Return true iff arg is 2**n for some n > 0 -* T should be an unsigned integer type +/** +* Power of 2 test. T should be an unsigned integer type +* @param arg an integer value +* @return true iff arg is 2^n for some n > 0 */ template<typename T> inline bool power_of_2(T arg) @@ -22,9 +23,11 @@ inline bool power_of_2(T arg) return ((arg != 0 && arg != 1) && ((arg & (arg-1)) == 0)); } -/* +/** * Return the index of the highest set bit * T is an unsigned integer type +* @param n an integer value +* @return index of the highest set bit in n */ template<typename T> inline u32bit high_bit(T n) @@ -35,8 +38,11 @@ inline u32bit high_bit(T n) return 0; } -/* +/** * Return the index of the lowest set bit +* T is an unsigned integer type +* @param n an integer value +* @return index of the lowest set bit in n */ template<typename T> inline u32bit low_bit(T n) @@ -47,8 +53,10 @@ inline u32bit low_bit(T n) return 0; } -/* +/** * Return the number of significant bytes in n +* @param n an integer value +* @return number of significant bytes in n */ template<typename T> inline u32bit significant_bytes(T n) @@ -59,8 +67,10 @@ inline u32bit significant_bytes(T n) return 0; } -/* -* Return the Hamming weight of n +/** +* Compute Hamming weights +* @param n an integer value +* @return number of bits in n set to 1 */ template<typename T> inline u32bit hamming_weight(T n) @@ -74,8 +84,10 @@ inline u32bit hamming_weight(T n) return weight; } -/* +/** * Count the trailing zero bits in n +* @param n an integer value +* @return maximum x st 2^x divides n */ template<typename T> inline u32bit ctz(T n) |