This question is similar to Exercise 5.40 except that we wish to add support for four-operand arithmetic instructions such as add3, which adds three numbers together instead of two: add3 $t5, $t6, $t7, $t8 # $t5 = $t6 + $t7 + $t8 Assume that the instruction set is modified by introducing a new instruction format similar to the R-format except that bits [04] are used to specify the additional register (we still use rs, rt, and rd) and of course a new opcode is used. Your solution should not rely on adding additional read ports to the register file, nor should a new ALU be used.