2. To see how different ISA decisions will impact the machine design, consider designing an accumulator machine with the following specifications:

• 2²⁴ words of memory [words are 32-bit wide]
• Fixed format instructions
• A 32-bit accumulator register (AC)
• An index register X
• Index address mode: address field + X when indexing is indicated in the instruction
• Capable of performing a total of 128 operations

1. Write the equivalent machine level language corresponding to a C statement of

C = A + B

b. Give an instruction format for this computer. To do this draw a diagram of the instruction format with each field clearly specified.

For each field indicate its size, the reason for selected size, and a description of what purpose the field.