diff options
Diffstat (limited to 'src/lib/utils/ct_utils.h')
-rw-r--r-- | src/lib/utils/ct_utils.h | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/src/lib/utils/ct_utils.h b/src/lib/utils/ct_utils.h index 52a3bc388..2ea07b382 100644 --- a/src/lib/utils/ct_utils.h +++ b/src/lib/utils/ct_utils.h @@ -51,6 +51,12 @@ inline void unpoison(T* p, size_t n) #endif } +template<typename T> +inline void unpoison(T& p) + { + unpoison(&p, 1); + } + /* * T should be an unsigned machine integer type * Expand to a mask used for other operations @@ -90,6 +96,16 @@ inline T is_equal(T x, T y) } template<typename T> +inline T is_less(T x, T y) + { + /* + This expands to a constant time sequence with GCC 5.2.0 on x86-64 + but something more complicated may be needed for portable const time. + */ + return expand_mask<T>(x < y); + } + +template<typename T> inline void conditional_copy_mem(T value, T* to, const T* from0, @@ -102,6 +118,26 @@ inline void conditional_copy_mem(T value, to[i] = CT::select(mask, from0[i], from1[i]); } +template<typename T> +inline T expand_top_bit(T a) + { + return expand_mask<T>(a >> (sizeof(T)*8-1)); + } + +template<typename T> +inline T max(T a, T b) + { + const T a_larger = b - a; // negative if a is larger + return select(expand_top_bit(a), a, b); + } + +template<typename T> +inline T min(T a, T b) + { + const T a_larger = b - a; // negative if a is larger + return select(expand_top_bit(b), b, a); + } + } } |