MARIE
CS27 1
MARIE, a Machine Architecture that is Really Intuitive and Easy, is a simple architecture consisting of
memory (to store programs and data) and a CPU (consisting of an ALU and several registers). It has all
the functional components necessary to be a real working computer.
The MARIE Architecture
MARIE has the following characteristics:
• Binary, two’s complement
• Stored program, fixed word length
• Word (but not byte) addressable
• 4K words of main memory (this implies 12-bit addresses)
• 16-bit words
• 16-bit instructions: 4 bits for opcode and 12 for the address
• A 16-bit accumulator (AC)
• A 16-bit instruction register (IR)
• A 16-bit memory buffer register (MBR)
• A 12-bit program counter (PC)
• A 12-bit memory address register (MAR)
• An 8-bit input register
• An 8-bit output register
Figure 1 MARIE's Architecture
