Assume that we would like to expand the MIPS register file to 128 and keep the size of all other fields as in the original MPIS instruction set. How could it decrease the size of an MIPS assembly program

These changes has the ability to decrease the size of a program, it

can do so by going ahead to reduce the instances in which the register contents "spill" into other registers or memory, it also does so by allowing more complex operations to be implemented in one instruction as agianst requiring multiple instructions.

On the other hand they are likely able to increase the size of a program by requiring adding bits to the opcode and register fields, thereby increasing memory width

Explanation:

See answer

changes of the MIPS register file has the ability to decrease the size of a program because it gives room for "spill" when it reduces the instances in a register

Explanation:

changes of the MIPS register file has the ability to decrease the size of a program because it gives room for "spill" when it reduces the instances in a register, this therefore causes the contents of the register to spill into other registers or free memories.

The execution of complex operations in one instruction against execution of complex operations using multiple instructions is one of the effects of the changes on the MIPS register file. it can as well increase the memory width because it is more likely to increase the size of a program contained in the register