Chapter A, Problem 3E

Explanation of Solution

Safety of $\$k0$and$\$k1$:

$\$k0$ and $\$k1$ are used as aliases for registers $\$26$ and $\$27$.

The interrupt handler is allowed to use $\$k0$ and $\$k1$ without having to save or restore their values. This allows just enough leeway to start saving registers, as well as making returning from the interrupt handler possible