5.2 Rewrite the following CISC-style program fragment so that it executes correctly on a RISC (load-store) processor that executes the GPR ISA outlined in the previous chapter. Assume that the GPR ISA provides only the register addressing mode, and that there are enough registers in the processor to hold any temporary values that you need to generate. ADD r3, (r1), (r2) SUB r4, r3, (r5) MUL (r6), r7, r4