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Updated is my code constant time? (markdown)

Sun Yimin 2022-08-16 11:30:54 +08:00
parent 8b6f982d3b
commit 1ed25116a3
1 changed files with 2 additions and 2 deletions
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is-my-code-constant-time?.md

@ -37,12 +37,12 @@ __INLINE void cpSM2KE_reduction_x2w(BNU_CHUNK_T *r, const BNU_CHUNK_T *a, const
const int w = ((elemBits + 1) / 2 - 1);
/* compute copy BNU_CHUNK */
const int num_copy_bc = (w + (BNU_CHUNK_BITS - 1)) / BNU_CHUNK_BITS; // 2
const int num_copy_bc = (w + (BNU_CHUNK_BITS - 1)) / BNU_CHUNK_BITS; // 2, 假定BNU_CHUNK_BITS=64
const int num_bit_shift = (w - (num_copy_bc - 1) * BNU_CHUNK_BITS); // 63
const BNU_CHUNK_T vadd = (BNU_CHUNK_T)(1ULL << num_bit_shift); // 1<<63 = 0x8000000000000000
const BNU_CHUNK_T mask = (BNU_CHUNK_T)(vadd - 1); // 0x7fffffffffffffff
ZEXPAND_COPY_BNU(r, elemSize, a, num_copy_bc); // copy 2 64 bits of a to r
ZEXPAND_COPY_BNU(r, elemSize, a, num_copy_bc); // copy 2 64 bits from a to r
r[num_copy_bc - 1] = (r[num_copy_bc - 1] & mask) + vadd;
return;
}