The following code computes the 128-bit product of two 64-bit signed values x and y and...

The following code computes the 128-bit product of two 64-bit signed values x and y and stores the result in memory:

Gcc generates the following assembly code implementing the computation:

This code uses three multiplications for the muitiprecision arithmetic required to implement 128-bit arithmetic on a 64-bit machine. Describe the algorithm used to compute the product, and annotate the assembly code to show how it realizes your algorithm. Hint When extending arguments of x and y to 128 bits, they can be rewritten as x = 2⁶⁴ . are 64-bit values. Similarly, the 128-bit product can be written as p = 2⁶⁴ p_h + p_l where are 64-bit values. Show how the code computes the values of in terms of