Functions

Calculate a + b + carry, returning the sum and modifying the carry value.
Calculate a + b * c, returning the lower 64 bits of the result and setting carry to the upper 64 bits.
Calculate a + b * c, discarding the lower 64 bits of the result and setting carry to the upper 64 bits.
Calculate a + (b * c) + carry, returning the least significant digit and setting carry to the most significant digit.
set a = a - b - borrow, and returning the borrow value.