4.8   MARIE

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. MARIE will help to illustrate the concepts in this and the preceding three chapters. We describe MARIE’s architecture in the following sections.

4.8.1   The 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 bits per address)

  • 16-bit data (words have 16 bits)

  • 16-bit instructions: 4 for the opcode and 12 for the address

  • A 16-bit ...

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