condSub
private fn
void condSub(ref ubyte[64] t, scope const ref ubyte[64] d) nothrow @trusted @nogcSubtracts d from t when t >= d, branchlessly.
The difference is always computed; a mask derived from the final borrow selects between the difference and the original value, so no control flow depends on the comparison.
Parameters
t | Minuend and destination. |
d | Subtrahend. |