The exported `gcd_u64` returns the greatest common divisor of two `u64` operands, computed by the binary-GCD (Stein's) algorithm. The `num-integer` convention `gcd(0, 0) = 0` is preserved. The `initi
The exported `swap_elements` swaps two elements of a `[u64]` slice in place. Informal spec. Given indices `i, j` both in bounds (`< len`) and an array region `[ptr, ptr + 8 * len)` that sits at or ab